Sample records for helium reactor gt-mhr

  1. GT-MHR COMMERCIALIZATION STUDY FINAL CONTRACTUAL REPORT OF WORK PERFORMED FROM CONTRACT BEGINNING, JUNE 18,2001,TO CONTRACT END, JANUARY 31,2004

    SciTech Connect (OSTI)

    SHENOY, AS

    2004-02-01T23:59:59.000Z

    OAK-B135 This is the final report of work performed by General Atomics on a Gas Turbine Modular Helium Reactor (GT-MHR) commercialization study under contract to the Department of Energy, Oakland Operations Office. The contract work scope covered a series of discrete tasks relating to commercialization of the GT-MHR. During the first year of performance, June 18, 2001--June 30, 2002, the contract covered six tasks, Tasks 1 through 6. Subsequently, four additional tasks were added, Tasks 7,8,10 and 11. With the exception of Task 1, each of the contract Tasks involved the development of one or more discrete deliverable products. Task 1 covered activities performed by General Atomics as part of a several year fuel irradiation testing activity being conducted in cooperation with the European Union. The irradiation testing will not be completed for three or more years into the future. Future work by General Atomics on this irradiation test activity will be covered by a new contract.

  2. Evaluation of the Gas Turbine Modular Helium Reactor

    SciTech Connect (OSTI)

    Not Available

    1994-02-01T23:59:59.000Z

    Recent advances in gas-turbine and heat exchanger technology have enhanced the potential for a Modular Helium Reactor (MHR) incorporating a direct gas turbine (Brayton) cycle for power conversion. The resulting Gas Turbine Modular Helium Reactor (GT-MHR) power plant combines the high temperature capabilities of the MHR with the efficiency and reliability of modern gas turbines. While the passive safety features of the steam cycle MHR (SC-MHR) are retained, generation efficiencies are projected to be in the range of 48% and steam power conversion systems, with their attendant complexities, are eliminated. Power costs are projected to be reduced by about 20%, relative to the SC-MHR or coal. This report documents the second, and final, phase of a two-part evaluation that concluded with a unanimous recommendation that the direct cycle (DC) variant of the GT-MHR be established as the commercial objective of the US Gas-Cooled Reactor Program. This recommendation has been endorsed by industrial and utility participants and accepted by the US Department of Energy (DOE). The Phase II effort, documented herein, concluded that the DC GT-MHR offers substantial technical and economic advantages over both the IDC and SC systems. Both the DC and IDC were found to offer safety advantages, relative to the SC, due to elimination of the potential for water ingress during power operations. This is the dominant consequence event for the SC. The IDC was judged to require somewhat less development than the direct cycle, while the SC, which has the greatest technology base, incurs the least development cost and risk. While the technical and licensing requirements for the DC were more demanding, they were judged to be incremental and feasible. Moreover, the DC offers significant performance and cost improvements over the other two concepts. Overall, the latter were found to justify the additional development needs.

  3. Deep-Burn Modular Helium Reactor Fuel Development Plan

    SciTech Connect (OSTI)

    McEachern, D

    2002-12-02T23:59:59.000Z

    This document contains the workscope, schedule and cost for the technology development tasks needed to satisfy the fuel and fission product transport Design Data Needs (DDNs) for the Gas Turbine-Modular Helium Reactor (GT-MHR), operating in its role of transmuting transuranic (TRU) nuclides in spent fuel discharged from commercial light-water reactors (LWRs). In its application for transmutation, the GT-MHR is referred to as the Deep-Burn MHR (DB-MHR). This Fuel Development Plan (FDP) describes part of the overall program being undertaken by the U.S. Department of Energy (DOE), utilities, and industry to evaluate the use of the GT-MHR to transmute transuranic nuclides from spent nuclear fuel. The Fuel Development Plan (FDP) includes the work on fuel necessary to support the design and licensing of the DB-MHR. The FDP is organized into ten sections. Section 1 provides a summary of the most important features of the plan, including cost and schedule information. Section 2 describes the DB-MHR concept, the features of its fuel and the plan to develop coated particle fuel for transmutation. Section 3 describes the knowledge base for fabrication of coated particles, the experience with irradiation performance of coated particle fuels, the database for fission product transport in HTGR cores, and describes test data and calculations for the performance of coated particle fuel while in a repository. Section 4 presents the fuel performance requirements in terms of as-manufactured quality and performance of the fuel coatings under irradiation and accident conditions. These requirements are provisional because the design of the DB-MHR is in an early stage. However, the requirements are presented in this preliminary form to guide the initial work on the fuel development. Section 4 also presents limits on the irradiation conditions to which the coated particle fuel can be subjected for the core design. These limits are based on past irradiation experience. Section 5 describes the Design Data Needs to: (1) fabricate the coated particle fuel, (2) predict its performance in the reactor core, (3) predict the radionuclide release rates from the reactor core, and (4) predict the performance of spent fuel in a geological repository. The heart of this fuel development plan is Section 6, which describes the development activities proposed to satisfy the DDNs presented in Section 5. The development scope is divided into Fuel Process Development, Fuel Materials Development, Fission Product Transport, and Spent Fuel Disposal. Section 7 describes the facilities to be used. Generally, this program will utilize existing facilities. While some facilities will need to be modified, there is no requirement for major new facilities. Section 8 states the Quality Assurance requirements that will be applied to the development activities. Section 9 presents detailed costs organized by WBS and spread over time. Section 10 presents a list of the types of deliverables that will be prepared in each of the WBS elements. Four Appendices contain supplementary information on: (a) design data needs, (b) the interface with the separations plant, (c) the detailed development schedule, and (d) the detailed cost estimate.

  4. Very High Temperature Reactor (VHTR) Survey of Materials Research and Development Needs to Support Early Deployment

    SciTech Connect (OSTI)

    Eric Shaber; G. Baccaglini; S. Ball; T. Burchell; B. Corwin; T. Fewell; M. Labar; P. MacDonald; P. Rittenhouse; Russ Vollam; F. Southworth

    2003-01-01T23:59:59.000Z

    The VHTR reference concept is a helium-cooled, graphite moderated, thermal neutron spectrum reactor with an outlet temperature of 1000 C or higher. It is expected that the VHTR will be purchased in the future as either an electricity producing plant with a direct cycle gas turbine or a hydrogen producing (or other process heat application) plant. The process heat version of the VHTR will require that an intermediate heat exchanger (IHX) and primary gas circulator be located in an adjoining power conversion vessel. A third VHTR mission - actinide burning - can be accomplished with either the hydrogen-production or gas turbine designs. The first ''demonstration'' VHTR will produce both electricity and hydrogen using the IHX to transfer the heat to either a hydrogen production plant or the gas turbine. The plant size, reactor thermal power, and core configuration will be designed to assure passive decay heat removal without fuel damage during accidents. The fuel cycle will be a once-through very high burnup low-enriched uranium fuel cycle. The purpose of this report is to identify the materials research and development needs for the VHTR. To do this, we focused on the plant design described in Section 2, which is similar to the GT-MHR plant design (850 C core outlet temperature). For system or component designs that present significant material challenges (or far greater expense) there may be some viable design alternatives or options that can reduce development needs or allow use of available (cheaper) materials. Nevertheless, we were not able to assess those alternatives in the time allotted for this report and, to move forward with this material research and development assessment, the authors of this report felt that it was necessary to use a GT-MHR type design as the baseline design.

  5. The Modular Helium Reactor for Hydrogen Production

    SciTech Connect (OSTI)

    E. Harvego; M. Richards; A. Shenoy; K. Schultz; L. Brown; M. Fukuie

    2006-10-01T23:59:59.000Z

    For electricity and hydrogen production, an advanced reactor technology receiving considerable international interest is a modular, passively-safe version of the high-temperature, gas-cooled reactor (HTGR), known in the U.S. as the Modular Helium Reactor (MHR), which operates at a power level of 600 MW(t). For hydrogen production, the concept is referred to as the H2-MHR. Two concepts that make direct use of the MHR high-temperature process heat are being investigated in order to improve the efficiency and economics of hydrogen production. The first concept involves coupling the MHR to the Sulfur-Iodine (SI) thermochemical water splitting process and is referred to as the SI-Based H2-MHR. The second concept involves coupling the MHR to high-temperature electrolysis (HTE) and is referred to as the HTE-Based H2-MHR.

  6. Liquid uranium alloy-helium fission reactor

    DOE Patents [OSTI]

    Minkov, Vladimir (Skokie, IL)

    1986-01-01T23:59:59.000Z

    This invention teaches a nuclear fission reactor having a core vessel and at least one tandem heat exchanger vessel coupled therewith across upper and lower passages to define a closed flow loop. Nuclear fuel such as a uranium alloy in its liquid phase fills these vessels and flow passages. Solid control elements in the reactor core vessel are adapted to be adjusted relative to one another to control fission reaction of the liquid fuel therein. Moderator elements in the other vessel and flow passages preclude fission reaction therein. An inert gas such as helium is bubbled upwardly through the heat exchanger vessel operable to move the liquid fuel upwardly therein and unidirectionally around the closed loop and downwardly through the core vessel. This helium gas is further directed to heat conversion means outside of the reactor vessels to utilize the heat from the fission reaction to generate useful output. The nuclear fuel operates in the 1200.degree.-1800.degree. C. range, and even higher to 2500.degree. C., limited only by the thermal effectiveness of the structural materials, increasing the efficiency of power generation from the normal 30-35% with 300.degree.-500.degree. C. upper limit temperature to 50-65%. Irradiation of the circulating liquid fuel, as contrasted to only localized irradiation of a solid fuel, provides improved fuel utilization.

  7. Liquid uranium alloy-helium fission reactor

    DOE Patents [OSTI]

    Minkov, V.

    1984-06-13T23:59:59.000Z

    This invention describes a nuclear fission reactor which has a core vessel and at least one tandem heat exchanger vessel coupled therewith across upper and lower passages to define a closed flow loop. Nuclear fuel such as a uranium alloy in its liquid phase fills these vessels and flow passages. Solid control elements in the reactor core vessel are adapted to be adjusted relative to one another to control fission reaction of the liquid fuel therein. Moderator elements in the other vessel and flow passages preclude fission reaction therein. An inert gas such as helium is bubbled upwardly through the heat exchanger vessel operable to move the liquid fuel upwardly therein and unidirectionally around the closed loop and downwardly through the core vessel. This helium gas is further directed to heat conversion means outside of the reactor vessels to utilize the heat from the fission reaction to generate useful output. The nuclear fuel operates in the 1200 to 1800/sup 0/C range, and even higher to 2500/sup 0/C.

  8. Computational Fluid Dynamics Analyses on Very High Temperature Reactor Air Ingress

    SciTech Connect (OSTI)

    Chang H Oh; Eung S. Kim; Richard Schultz; David Petti; Hyung S. Kang

    2009-07-01T23:59:59.000Z

    A preliminary computational fluid dynamics (CFD) analysis was performed to understand density-gradient-induced stratified flow in a Very High Temperature Reactor (VHTR) air-ingress accident. Various parameters were taken into consideration, including turbulence model, core temperature, initial air mole-fraction, and flow resistance in the core. The gas turbine modular helium reactor (GT-MHR) 600 MWt was selected as the reference reactor and it was simplified to be 2-D geometry in modeling. The core and the lower plenum were assumed to be porous bodies. Following the preliminary CFD results, the analysis of the air-ingress accident has been performed by two different codes: GAMMA code (system analysis code, Oh et al. 2006) and FLUENT CFD code (Fluent 2007). Eventually, the analysis results showed that the actual onset time of natural convection (~160 sec) would be significantly earlier than the previous predictions (~150 hours) calculated based on the molecular diffusion air-ingress mechanism. This leads to the conclusion that the consequences of this accident will be much more serious than previously expected.

  9. Fundamental Thermal Fluid Physics of High Temperature Flows in Advanced Reactor Systems - Nuclear Energy Research Initiative Program Interoffice Work Order (IWO) MSF99-0254 Final Report for Period 1 August 1999 to 31 December 2002

    SciTech Connect (OSTI)

    McEligot, D.M.; Condie, K.G.; Foust, T.D.; McCreery, G.E.; Pink, R.J.; Stacey, D.E. (INEEL); Shenoy, A.; Baccaglini, G. (General Atomics); Pletcher, R.H. (Iowa State U.); Wallace, J.M.; Vukoslavcevic, P. (U. Maryland); Jackson, J.D. (U. Manchester, UK); Kunugi, T. (Kyoto U., Japan); Satake, S.-i. (Tokyo U. Science, Japan)

    2002-12-31T23:59:59.000Z

    The ultimate goal of the study is the improvement of predictive methods for safety analyses and design of advanced reactors for higher efficiency and enhanced safety and for deployable reactors for electrical power generation, process heat utilization and hydrogen generation. While key applications would be advanced gas-cooled reactors (AGCRs) using the closed Brayton cycle (CBC) for higher efficiency (such as the proposed Gas Turbine - Modular Helium Reactor (GT-MHR) of General Atomics [Neylan and Simon, 1996]), results of the proposed research should also be valuable in reactor systems with supercritical flow or superheated vapors, e.g., steam. Higher efficiency leads to lower cost/kwh and reduces life-cycle impacts of radioactive waste (by reducing waters/kwh). The outcome will also be useful for some space power and propulsion concepts and for some fusion reactor concepts as side benefits, but they are not the thrusts of the investigation. The objective of the project is to provide fundamental thermal fluid physics knowledge and measurements necessary for the development of the improved methods for the applications.

  10. Helium bubble distributions in reactor tank repair specimens

    SciTech Connect (OSTI)

    Tosten, M.H.; Kestin, P.A.

    1992-03-01T23:59:59.000Z

    This report discusses the Reactor Tank Repair (RTR) program was initiated to develop an in-tank repair process capable of repairing stress corrosion cracks within the SRS reactor tank walls, in the event that such a repair is needed. Previous attempts to repair C-reactor tank with a gas tungsten arc (GTA) welding process were unsuccessful due to significant cracking that occurred in the heat-affected-zones adjacent to the repair welds. It was determined that this additional cracking was a result of helium embrittlement caused by the combined effects of helium (existing within the tank walls), the high heat input associated with the GTA process, and weld shrinkage stresses. Based on the results of earlier studies it was suggested that the effects of helium embrittlement could be minimized by using a low heat input GMA process. Metallographic analysis played an important role throughout the investigation of alternative welding methods for the repair of helium-containing materials.

  11. Investigation of Countercurrent Helium-Air Flows in Air-ingress Accidents for VHTRs

    SciTech Connect (OSTI)

    Sun, Xiaodong; Christensen, Richard; Oh, Chang

    2013-10-03T23:59:59.000Z

    The primary objective of this research is to develop an extensive experimental database for the air- ingress phenomenon for the validation of computational fluid dynamics (CFD) analyses. This research is intended to be a separate-effects experimental study. However, the project team will perform a careful scaling analysis prior to designing a scaled-down test facility in order to closely tie this research with the real application. As a reference design in this study, the team will use the 600 MWth gas turbine modular helium reactor (GT-MHR) developed by General Atomic. In the test matrix of the experiments, researchers will vary the temperature and pressure of the helium— along with break size, location, shape, and orientation—to simulate deferent scenarios and to identify potential mitigation strategies. Under support of the Department of Energy, a high-temperature helium test facility has been designed and is currently being constructed at Ohio State University, primarily for high- temperature compact heat exchanger testing for the VHTR program. Once the facility is in operation (expected April 2009), this study will utilize high-temperature helium up to 900°C and 3 MPa for loss-of-coolant accident (LOCA) depressurization and air-ingress experiments. The project team will first conduct a scaling study and then design an air-ingress test facility. The major parameter to be measured in the experiments is oxygen (or nitrogen) concentration history at various locations following a LOCA scenario. The team will use two measurement techniques: 1) oxygen (or similar type) sensors employed in the flow field, which will introduce some undesirable intrusiveness, disturbing the flow, and 2) a planar laser-induced fluorescence (PLIF) imaging technique, which has no physical intrusiveness to the flow but requires a transparent window or test section that the laser beam can penetrate. The team will construct two test facilities, one for high-temperature helium tests with local sensors and the other for low- temperature helium tests with the PLIF technique. The results from the two instruments will provide a means to cross-calibrate the measurement techniques.

  12. Preliminary materials selection issues for the next generation nuclear plant reactor pressure vessel.

    SciTech Connect (OSTI)

    Natesan, K.; Majumdar, S.; Shankar, P. S.; Shah, V. N.; Nuclear Engineering Division

    2007-03-21T23:59:59.000Z

    In the coming decades, the United States and the entire world will need energy supplies to meet the growing demands due to population increase and increase in consumption due to global industrialization. One of the reactor system concepts, the Very High Temperature Reactor (VHTR), with helium as the coolant, has been identified as uniquely suited for producing hydrogen without consumption of fossil fuels or the emission of greenhouse gases [Generation IV 2002]. The U.S. Department of Energy (DOE) has selected this system for the Next Generation Nuclear Plant (NGNP) Project, to demonstrate emissions-free nuclear-assisted electricity and hydrogen production within the next 15 years. The NGNP reference concepts are helium-cooled, graphite-moderated, thermal neutron spectrum reactors with a design goal outlet helium temperature of {approx}1000 C [MacDonald et al. 2004]. The reactor core could be either a prismatic graphite block type core or a pebble bed core. The use of molten salt coolant, especially for the transfer of heat to hydrogen production, is also being considered. The NGNP is expected to produce both electricity and hydrogen. The process heat for hydrogen production will be transferred to the hydrogen plant through an intermediate heat exchanger (IHX). The basic technology for the NGNP has been established in the former high temperature gas reactor (HTGR) and demonstration plants (DRAGON, Peach Bottom, AVR, Fort St. Vrain, and THTR). In addition, the technologies for the NGNP are being advanced in the Gas Turbine-Modular Helium Reactor (GT-MHR) project, and the South African state utility ESKOM-sponsored project to develop the Pebble Bed Modular Reactor (PBMR). Furthermore, the Japanese HTTR and Chinese HTR-10 test reactors are demonstrating the feasibility of some of the planned components and materials. The proposed high operating temperatures in the VHTR place significant constraints on the choice of material selected for the reactor pressure vessel for both the PBMR and prismatic design. The main focus of this report is the RPV for both design concepts with emphasis on material selection.

  13. ANALYSIS OF SEPCTRUM CHOICES FOR SMALL MODULAR REACTORS-PERFORMANCE AND DEVELOPMENT

    E-Print Network [OSTI]

    Kafle, Nischal

    2011-04-26T23:59:59.000Z

    the world; CAREM in Argentina, HTR-PM in China, FUJI in Japan, BREST, KLT series, SVBR-100, and VK-300 in Russia, PBMR (Pebble Bed Modular Reactor) in South Africa, SMART in South Korea, mPower, NuScale, GT- MHR in United States of America, and many... Association, 2011). 3 CAREM CAREM is a pressurized water reactor being studied in Argentina by INVAP (World Nuclear Association, 2010). This reactor uses 3.4% enriched uranium, and can produce 27 MWe which can be extendable to more than 300MWe...

  14. Assessment of passive decay heat removal in the General Atomics Modular Helium Reactor 

    E-Print Network [OSTI]

    Cocheme, Francois Guilhem

    2005-02-17T23:59:59.000Z

    that began in the 1950?s. The concept features a helium gas cooled reactor with a graphite moderated prismatic core that contains TRISO fuel. This study evaluates the passive decay heat removal capabilities of the MHR under abnormal conditions, more...

  15. Remote reactor repair: GTA (gas tungsten Arc) weld cracking caused by entrapped helium

    SciTech Connect (OSTI)

    Kanne, W.R. Jr.

    1988-01-01T23:59:59.000Z

    A repair patch was welded to the wall of a nuclear reactor tank using remotely controlled thirty-foot long robot arms. Further repair was halted when gas tungsten arc (GTA) welds joining type 304L stainless steel patches to the 304 stainless steel wall developed toe cracks in the heat-affected zone (HAZ). The role of helium in cracking was investigated using material with entrapped helium from tritium decay. As a result of this investigation, and of an extensive array of diagnostic tests performed on reactor tank wall material, helium embrittlement was shown to be the cause of the toe cracks.

  16. Material Control and Accounting Design Considerations for High-Temperature Gas Reactors

    SciTech Connect (OSTI)

    Trond Bjornard; John Hockert

    2011-08-01T23:59:59.000Z

    The subject of this report is domestic safeguards and security by design (2SBD) for high-temperature gas reactors, focusing on material control and accountability (MC&A). The motivation for the report is to provide 2SBD support to the Next Generation Nuclear Plant (NGNP) project, which was launched by Congress in 2005. This introductory section will provide some background on the NGNP project and an overview of the 2SBD concept. The remaining chapters focus specifically on design aspects of the candidate high-temperature gas reactors (HTGRs) relevant to MC&A, Nuclear Regulatory Commission (NRC) requirements, and proposed MC&A approaches for the two major HTGR reactor types: pebble bed and prismatic. Of the prismatic type, two candidates are under consideration: (1) GA's GT-MHR (Gas Turbine-Modular Helium Reactor), and (2) the Modular High-Temperature Reactor (M-HTR), a derivative of Areva's Antares reactor. The future of the pebble-bed modular reactor (PBMR) for NGNP is uncertain, as the PBMR consortium partners (Westinghouse, PBMR [Pty] and The Shaw Group) were unable to agree on the path forward for NGNP during 2010. However, during the technology assessment of the conceptual design phase (Phase 1) of the NGNP project, AREVA provided design information and technology assessment of their pebble bed fueled plant design called the HTR-Module concept. AREVA does not intend to pursue this design for NGNP, preferring instead a modular reactor based on the prismatic Antares concept. Since MC&A relevant design information is available for both pebble concepts, the pebble-bed HTGRs considered in this report are: (1) Westinghouse PBMR; and (2) AREVA HTR-Module. The DOE Office of Nuclear Energy (DOE-NE) sponsors the Fuel Cycle Research and Development program (FCR&D), which contains an element specifically focused on the domestic (or state) aspects of SBD. This Material Protection, Control and Accountancy Technology (MPACT) program supports the present work summarized in this report, namely the development of guidance to support the consideration of MC&A in the design of both pebble-bed and prismatic-fueled HTGRs. The objective is to identify and incorporate design features into the facility design that will cost effectively aid in making MC&A more effective and efficient, with minimum impact on operations. The theft of nuclear material is addressed through both MC&A and physical protection, while the threat of sabotage is addressed principally through physical protection.

  17. Design modification for the modular helium reactor for higher temperature operation and reliability studies for nuclear hydrogen production processes

    E-Print Network [OSTI]

    Reza, S.M. Mohsin

    2009-05-15T23:59:59.000Z

    Design options have been evaluated for the Modular Helium Reactor (MHR) for higher temperature operation. An alternative configuration for the MHR coolant inlet flow path is developed to reduce the peak vessel temperature (PVT). The coolant inlet...

  18. A helium-cooled blanket design of the low aspect ratio reactor

    SciTech Connect (OSTI)

    Wong, C.P.; Baxi, C.B.; Reis, E.E. [General Atomics, San Diego, CA (United States); Cerbone, R.; Cheng, E.T. [TSI Research, Solana Beach, CA (United States)

    1998-03-01T23:59:59.000Z

    An aggressive low aspect ratio scoping fusion reactor design indicated that a 2 GW(e) reactor can have a major radius as small as 2.9 m resulting in a device with competitive cost of electricity at 49 mill/kWh. One of the technology requirements of this design is a high performance high power density first wall and blanket system. A 15 MPa helium-cooled, V-alloy and stagnant LiPb breeder first wall and blanket design was utilized. Due to the low solubility of tritium in LiPb, there is the concern of tritium migration and the formation of V-hydride. To address these issues, a lithium breeder system with high solubility of tritium has been evaluated. Due to the reduction of blanket energy multiplication to 1.2, to maintain a plant Q of > 4, the major radius of the reactor has to be increased to 3.05 m. The inlet helium coolant temperature is raised to 436 C in order to meet the minimum V-alloy temperature limit everywhere in the first wall and blanket system. To enhance the first wall heat transfer, a swirl tape coolant channel design is used. The corresponding increase in friction factor is also taken into consideration. To reduce the coolant system pressure drop, the helium pressure is increased from 15 to 18 MPa. Thermal structural analysis is performed for a simple tube design. With an inside tube diameter of 1 cm and a wall thickness of 1.5 mm, the lithium breeder can remove an average heat flux and neutron wall loading of 2 and 8 MW/m(2), respectively. This reference design can meet all the temperature and material structural design limits, as well as the coolant velocity limits. Maintaining an outlet coolant temperature of 650 C, one can expect a gross closed cycle gas turbine thermal efficiency of 45%. This study further supports the use of helium coolant for high power density reactor design. When used with the low aspect ratio reactor concept a competitive fusion reactor can be projected at 51.9 mill/kWh.

  19. Design of an Alternative Coolant Inlet Flow Configuaration for the Modular Helium Reactor

    SciTech Connect (OSTI)

    SM Mohsin Reza; E. A. Harvego; Matt Richards; Arkal Shenoy; Kenneth Lee Peddicord

    2006-06-01T23:59:59.000Z

    The coolant outlet temperature for the Modular Helium Reactor (MHR) was increased to improve the overall efficiency of nuclear hydrogen production using either thermochemical or high temperature electrolysis (HTE) processes. The inlet temperature was also increased to keep about the same _T across the reactor core. Thermal hydraulic analyses of the current MHR design were performed with these updated temperatures to determine the impact of these highter temperatures on pressure drops, coolant flow rates and temperature profiles within the vessel and core regions. Due to these increased operating temperatures, the overall efficiency of hydrogen production processes increases but the steady state reactor vessel temperature is found to be well above the ASME code limits for current vessel materials. Using the RELAP5-3D/ATHENA computer code, an alternative configuration for the MHR coolant inlet flow path was evaluated in an attempt to reduce the reactor vessel temperatures. The coolant inlet flow was shifted from channel boxes located in the annular region between the reactor core barrel and the inner wall of the reactor vessel to a flow path through the outer permanent reflector. Considering the available thickness of graphite in the permanent outer reflector, the total flow area, the number of coolant holes and the coolant-hole diameter were varied to optimize the pressure drop, the coolant inlet velocity and the percentage of graphite removed from the core. The resulting thermal hydraulic analyses of the optimized design showed that peak vessel and fuel temperatures were within acceptable limits for both steady-state and transient operating conditions.

  20. High-temperature gas-cooled reactor helium compatibility studies: results of 10,000-hour exposure of selected alloys in simulated reactor helium

    SciTech Connect (OSTI)

    Lechtenberg, T.A.; Stevenson, R.D.; Johnson, W.R.

    1980-05-01T23:59:59.000Z

    Work on the HTGR Helium Compatibility Task accomplished during the period March 31, 1977 through September 30, 1979, is documented in this report. Emphasis is on the results and analyses of creep data to 10,000 h and the detailed metallurgical evaluations performed on candidate alloy specimens tested for up to 10,000 h. Long-term creep and unstressed aging data in controlled-impurity helium and in air at 800, 900, and 1000/sup 0/C are reported for alloys included in the program in FY-76, including the wrought solid-solution-strengthened alloys, Hastelloy X, Hastelloy S, RA 333, and HD 556, and the centrifugally cast austenitic alloys, HK 40, Supertherm, Manaurite 36X, Manaurite 36XS, and Manaurite 900.

  1. Unknown (Native) 5 

    E-Print Network [OSTI]

    James R. Manhart

    2011-08-10T23:59:59.000Z

    capabilities and code validation, a model of the GT-MHR reactor pressure vessel (RPV) was developed. Based on the currently available data, a model of the NGNP RPV was then developed through modifying the GT-MHR RPV model. For both RPV models, coolant outlet...

  2. A passively-safe fusion reactor blanket with helium coolant and steel structure

    SciTech Connect (OSTI)

    Crosswait, K.M.

    1994-04-01T23:59:59.000Z

    Helium is attractive for use as a fusion blanket coolant for a number of reasons. It is neutronically and chemically inert, nonmagnetic, and will not change phase during any off-normal or accident condition. A significant disadvantage of helium, however, is its low density and volumetric heat capacity. This disadvantage manifests itself most clearly during undercooling accident conditions such as a loss of coolant accident (LOCA) or a loss of flow accident (LOFA). This thesis describes a new helium-cooled tritium breeding blanket concept which performs significantly better during such accidents than current designs. The proposed blanket uses reduced-activation ferritic steel as a structural material and is designed for neutron wall loads exceeding 4 MW/m{sup 2}. The proposed geometry is based on the nested-shell concept developed by Wong, but some novel features are used to reduce the severity of the first wall temperature excursion. These features include the following: (1) A ``beryllium-joint`` concept is introduced, which allows solid beryllium slabs to be used as a thermal conduction path from the first wall to the cooler portions of the blanket. The joint concept allows for significant swelling of the beryllium (10 percent or more) without developing large stresses in the blanket structure. (2) Natural circulation of the coolant in the water-cooled shield is used to maintain shield temperatures below 100 degrees C, thus maintaining a heat sink close to the blanket during the accident. This ensures the long-term passive safety of the blanket.

  3. Plant Design and Cost Estimation of a Natural Circulation Lead-Bismuth Reactor with Helium Power Conversion Cycle

    E-Print Network [OSTI]

    Kim, D.

    The analysis of an indirect helium power conversion system with lead-bismuth natural circulation primary system has been performed. The work of this report is focused on 1) identifying the allowable design region for the ...

  4. HELIUM, SOLID 1 Helium, Solid

    E-Print Network [OSTI]

    Glyde, Henry R.

    HELIUM, SOLID 1 Helium, Solid Henry R. Glyde Introduction Helium was first solidified at the famous focused on the melting curve, the specific heat, and the thermal conductivity of solid helium as a test criterion of melting does not hold in solid helium. This pioneering work up to 1957 is elegantly

  5. Three-dimensional neutronics optimization of helium-cooled blanket for multi-functional experimental fusion-fission hybrid reactor (FDS-MFX)

    SciTech Connect (OSTI)

    Jiang, J.; Yuan, B.; Jin, M.; Wang, M.; Long, P.; Hu, L. [Inst. of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Univ. of Science and Technology of China, Hefei, Anhui, 230031 (China); School of Nuclear Science and Technology, Univ. of Science and Technology of China, No.350 Shushanhu Road, Shushan District, Hefei, Anhui, 230031 (China)

    2012-07-01T23:59:59.000Z

    Three-dimensional neutronics optimization calculations were performed to analyse the parameters of Tritium Breeding Ratio (TBR) and maximum average Power Density (PDmax) in a helium-cooled multi-functional experimental fusion-fission hybrid reactor named FDS (Fusion-Driven hybrid System)-MFX (Multi-Functional experimental) blanket. Three-stage tests will be carried out successively, in which the tritium breeding blanket, uranium-fueled blanket and spent-fuel-fueled blanket will be utilized respectively. In this contribution, the most significant and main goal of the FDS-MFX blanket is to achieve the PDmax of about 100 MW/m3 with self-sustaining tritium (TBR {>=} 1.05) based on the second-stage test with uranium-fueled blanket to check and validate the demonstrator reactor blanket relevant technologies based on the viable fusion and fission technologies. Four different enriched uranium materials were taken into account to evaluate PDmax in subcritical blanket: (i) natural uranium, (ii) 3.2% enriched uranium, (iii) 19.75% enriched uranium, and (iv) 64.4% enriched uranium carbide. These calculations and analyses were performed using a home-developed code VisualBUS and Hybrid Evaluated Nuclear Data Library (HENDL). The results showed that the performance of the blanket loaded with 64.4% enriched uranium was the most attractive and it could be promising to effectively obtain tritium self-sufficiency (TBR-1.05) and a high maximum average power density ({approx}100 MW/m{sup 3}) when the blanket was loaded with the mass of {sup 235}U about 1 ton. (authors)

  6. Helium Ion Microscope | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Helium Ion Microscope Helium Ion Microscope The Helium Ion Microscope promises to advance biological, geochemical, biogeochemical, and surfaceinterface studies using its combined...

  7. Helium Ion Microscope | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Helium Ion Microscope Helium Ion Microscope Bruce Arey discusses the capabilities of EMSL's new helium ion microscope housed in EMSL's Quiet Wing....

  8. October 15-19, 2000 R. Schleicher, A. R. Raffray, and C. P. Wong, An Assessment of the Brayton Cycle..., TOFE 2000 An Assessment of the Brayton Cycle for High

    E-Print Network [OSTI]

    Raffray, A. René

    CCGT (GT-MHR) Currently Being Designed by U.S./Russia ReactorPower Conversion Module Generator Turbine Efficiency is Optimized by Setting System Parameters Under the Designer's Control · Compressor turbine inlet-Term Possibility of Power Conversion with High Efficiency · Application of closed-cycle gas turbine (CCGT

  9. Cooling with Superfluid Helium

    E-Print Network [OSTI]

    Lebrun, P

    2014-01-01T23:59:59.000Z

    The technical properties of helium II (‘superfluid’ helium) are presented in view of its applications to the cooling of superconducting devices, particularly in particle accelerators. Cooling schemes are discussed in terms of heat transfer performance and limitations. Large-capacity refrigeration techniques below 2 K are reviewed, with regard to thermodynamic cycles as well as process machinery. Examples drawn from existing or planned projects illustrate the presentation. Keywords: superfluid helium, cryogenics

  10. H2-MHR Pre-Conceptual Design Report: SI-Based Plant; HTE-Based Plant

    SciTech Connect (OSTI)

    Matt Richards; A.S. Shenoy; L.C. Brown; R.T. Buckingham; E.A. Harvego; K.L. Peddicord; S.M.M. Reza; J.P. Coupey

    2006-04-19T23:59:59.000Z

    Hydrogen and electricity are expected to dominate the world energy system in the long term. The world currently consumes about 50 million metric tons of hydrogen per year, with the bulk of it being consumed by the chemical and refining industries. The demand for hydrogen is expected to increase, especially if the U.S. and other countries shift their energy usage towards a hydrogen economy, with hydrogen consumed as an energy commodity by the transportation, residential, and commercial sectors. However, there is strong motivation to not use fossil fuels in the future as a feedstock for hydrogen production, because the greenhouse gas carbon dioxide is a byproduct and fossil fuel prices are expected to increase significantly. For electricity and hydrogen production, an advanced reactor technology receiving considerable international interest is a modular, passively-safe version of the high-temperature, gas-cooled reactor (HTGR), known in the U.S. as the Modular Helium Reactor (MHR), which operates at a power level of 600 MW(t). For electricity production, the MHR operates with an outlet helium temperature of 850 C to drive a direct, Brayton-cycle power-conversion system (PCS) with a thermal-to-electrical conversion efficiency of 48 percent. This concept is referred to as the Gas Turbine MHR (GT-MHR). For hydrogen production, the process heat from the MHR is used to produce hydrogen. This concept is referred to as the H2-MHR.

  11. Final Technical Report for the Period September 2002 through September 2005; H2-MHR Pre-Conceptual Design Report: SI-Based Plant; H2-MHR Pre-Conceptual Design Report: HTE-Based Plant

    SciTech Connect (OSTI)

    M. Richards; A. Shenoy; L. Brown; R. Buckingham; E. Harvego; K. Peddicord; M. Reza; J. Coupey

    2006-04-19T23:59:59.000Z

    For electricity and hydrogen production, an advanced reactor technology receiving considerable international interest is a modular, passively-safe version of the high-temperature, gas-cooled reactor, known in the U.S. as the Modular Helium Reactor (MHR), which operates at a power level of 600 MW(t). For electricity production, the MHR operates with an outlet helium temperature of 850 C to drive a direct, Brayton-cycle power-conversion system with a thermal-to-electrical conversion efficiency of 48 percent. This concept is referred to as the Gas Turbine MHR (GT-MHR). For hydrogen production, both electricity and process heat from the MHR are used to produce hydrogen. This concept is referred to as the H2-MHR. This report provides pre-conceptual design descriptions of full-scale, nth-of-a-kind H2 MHR plants based on thermochemical water splitting using the Sulfur-Iodine process and High-Temperature Electrolysis.

  12. The Primordial Helium Abundance

    E-Print Network [OSTI]

    Manuel Peimbert

    2008-11-18T23:59:59.000Z

    I present a brief review on the determination of the primordial helium abundance by unit mass, Yp. I discuss the importance of the primordial helium abundance in: (a) cosmology, (b) testing the standard big bang nucleosynthesis, (c) studying the physical conditions in H II regions, (d) providing the initial conditions for stellar evolution models, and (e) testing the galactic chemical evolution models.

  13. Modularity of the MIT Pebble Bed Reactor for use by the commercial power industry

    E-Print Network [OSTI]

    Hanlon-Hyssong, Jaime E

    2008-01-01T23:59:59.000Z

    The Modular Pebble Bed Reactor is a small high temperature helium cooled reactor that is being considered for both electric power and hydrogen production. Pebble bed reactors are being developed in South Africa, China and ...

  14. SPECIAL TOPIC: HELIUM NANODROPLETS Experimental studies of helium droplets

    E-Print Network [OSTI]

    Northby, Jan A.

    SPECIAL TOPIC: HELIUM NANODROPLETS Experimental studies of helium droplets J. A. Northbya) Physics September 2001 In this report I will review experimental studies of free helium droplets, with the exception of spectroscopic studies of helium droplets that contain impurities. This particular topic, as well as theoretical

  15. RIS-M-2612 ON TRANSPORT OF HELIUM TO GRAIN BOUNDARIES DURING IRRADIATION

    E-Print Network [OSTI]

    parameters determining the integrity and lifetime of the structural components of a fusion reactor. A diffusion calculation i s made of the flux of helium to a grain boundary. The flux i s found to depend interior. The calculated accumulation of helium i s in good agreement with the measured gas content

  16. Economic Analysis of the Modular Pebble Bed Reactor

    E-Print Network [OSTI]

    data found inexisting cost data found in ""Evaluation of the Gas Turbine HeliumEvaluation of the Gas Turbine Helium ReactorReactor"" -- DOEDOE--HTGRHTGR--9038090380 -- Dec. 1993 and compared against an the gas prices price in 1992 was assumed constant and did not increase. This study win 1992 was assumed

  17. Helium Ash Simulation Studies with Divertor Helium Pumping in JET Internal Transport Barrier Discharges

    E-Print Network [OSTI]

    Helium Ash Simulation Studies with Divertor Helium Pumping in JET Internal Transport Barrier Discharges

  18. Cavity morphology in a Ni based superalloy under heavy ion irradiation with hot pre-injected helium. II

    SciTech Connect (OSTI)

    Zhang, He; Yao, Zhongwen, E-mail: yaoz@me.queensu.ca; Daymond, Mark R. [Department of Mechanical and Materials Engineering, Queen's University Kingston, Ontario K7L 3N6 (Canada); Kirk, Marquis A. [Material Science Division, Argonne National Laboratory Argonne, Illinois 60439 (United States)

    2014-03-14T23:59:59.000Z

    In the current investigation, TEM in-situ heavy ion (1?MeV Kr{sup 2+}) irradiation with helium pre-injected at elevated temperature (400?°C) was conducted to simulate in-reactor neutron irradiation induced damage in CANDU spacer material Inconel X-750, in an effort to understand the effects of helium on irradiation induced cavity microstructures. Three different quantities of helium, 400 appm, 1000 appm, and 5000 appm, were pre-injected directly into TEM foils at 400?°C. The samples containing helium were then irradiated in-situ with 1?MeV Kr{sup 2+} at 400?°C to a final dose of 5.4 dpa (displacement per atom). Cavities were formed from the helium injection solely and the cavity density and size increased with increasing helium dosage. In contrast to previous heavy ion irradiations with cold pre-injected helium, heterogeneous nucleation of cavities was observed. During the ensuing heavy ion irradiation, dynamical observation showed noticeable size increase in cavities which nucleated close to the grain boundaries. A “bubble-void” transformation was observed after Kr{sup 2+} irradiation to high dose (5.4?dpa) in samples containing 1000 appm and 5000 appm helium. Cavity distribution was found to be consistent with in-reactor neutron irradiation induced cavity microstructures. This implies that the distribution of helium is greatly dependent on the injection temperature, and helium pre-injection at high temperature is preferred for simulating the migration of the transmutation produced helium.

  19. Effects of sequential tungsten and helium ion implantation on nano-indentation hardness of tungsten

    SciTech Connect (OSTI)

    Armstrong, D. E. J.; Edmondson, P. D.; Roberts, S. G. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom)] [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom)

    2013-06-24T23:59:59.000Z

    To simulate neutron and helium damage in a fusion reactor first wall sequential self-ion implantation up to 13 dpa followed by helium-ion implantation up to 3000 appm was performed to produce damaged layers of {approx}2 {mu}m depth in pure tungsten. The hardness of these layers was measured using nanoindentation and was studied using transmission electron microscopy. Substantial hardness increases were seen in helium implanted regions, with smaller hardness increases in regions which had already been self-ion implanted, thus, containing pre-existing dislocation loops. This suggests that, for the same helium content, helium trapped in distributed vacancies gives stronger hardening than helium trapped in vacancies condensed into dislocation loops.

  20. Mining for Helium Jurriaan Hage

    E-Print Network [OSTI]

    Utrecht, Universiteit

    Mining for Helium Jurriaan Hage Peter van Keeken Department of Information and Computing Sciences-year functional programming course using the Helium compiler. The mining of such a collection is not trivial a type error. 1 #12;1 Introduction and motivation When the Helium compiler for learning Haskell

  1. Entanglement in helium

    E-Print Network [OSTI]

    Giuliano Benenti; Stefano Siccardi; Giuliano Strini

    2013-05-01T23:59:59.000Z

    Using a configuration-interaction variational method, we accurately compute the reduced, single-electron von Neumann entropy for several low-energy, singlet and triplet eigenstates of helium atom. We estimate the amount of electron-electron orbital entanglement for such eigenstates and show that it decays with energy.

  2. Development of charcoal sorbents for helium cryopumping

    SciTech Connect (OSTI)

    Sedgley, D.W.; Tobin, A.G.

    1985-09-30T23:59:59.000Z

    Improved methods for cryopumping helium were developed for application to fusion reactors where high helium generation rates are expected. This study period evaluated charcoal particle size, bonding agent type and thickness, and substrate thickness. The optimum combination of charcoal, bond, and substrate was used to form a scaled-up panel for evaluation in the Tritium Systems Test Assembly (TSTA) at Los Alamos. The optimum combination is a 12 x 30 mesh coconut charcoal attached to a 0.48 cm thick copper substrate by a 0.015 cm thick silver phosphorus copper braze. A copper cement bond for attaching charcoal to a substrate was identified and tested. Helium pumping performance of this combination was comparable to that of the charcoal braze system. Environmental tests showed the charcoal's susceptibility to vacuum chamber contamination. Performance degradation followed exposure of ambient temperature charcoal to a vacuum for prolonged periods. Maintaining a liquid nitrogen-cooled shield between the charcoal and the source of contamination prevented this degradation. A combination of bake-out and LN shielding effected recovery of degraded performance.

  3. Helium in Chemically Peculiar Stars

    E-Print Network [OSTI]

    F. Leone

    1998-05-05T23:59:59.000Z

    For the purpose of deriving the helium abundances in chemically peculiar stars, the importance of assuming a correct helium abundance has been investigated for determining the effective temperature and gravity of main sequence B-type stars, making full use of the present capability of reproducing their helium lines. Even if the flux distribution of main sequence B-type stars appears to depend only on the effective temperature for any helium abundance, the effective temperature, gravity and helium abundance have to be determined simultaneously by matching the Balmer line profiles. New MULTI NLTE calculations, performed adopting ATLAS9 model atmospheres and updated helium atomic parameters, reproduce most of the observed equivalent widths of neutral helium lines for main sequence B-type stars and they make us confident of the possibility to correctly derive the helium abundance in chemically peculiar stars. An application of previous methods to the helium rich star HD 37017 shows that helium could be stratified in the magnetic pole regions, as expected in the framework of the diffusion theory in the presence of mass loss.

  4. High Temperature Gas Reactors The Next Generation ?

    E-Print Network [OSTI]

    -Proof Advanced Reactor and Gas Turbine #12;Flow through Power Conversion Vessel 8 #12;9 TRISO Fuel Particle1 High Temperature Gas Reactors The Next Generation ? Professor Andrew C Kadak Massachusetts of Brayton vs. Rankine Cycle · High Temperature Helium Gas (900 C) · Direct or Indirect Cycle · Originally

  5. Pellet charge exchange helium measurement using neutral particle analyzer in large helical device

    SciTech Connect (OSTI)

    Ozaki, T.; Goncharov, P.; Veshchev, E.; Tamura, N.; Sudo, S.; Seki, T.; Kasahara, H. [High Energy Particle Group, Wave Heating Group and LHD Experimental Group, National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Takase, Y.; Ohsako, T. [Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8561 (Japan)

    2008-10-15T23:59:59.000Z

    It is very important to investigate the confinement of {alpha} particles, which will be produced by nuclear reactions in ITER and fusion reactors. The pellet charge exchange (PCX) measurement is one of the most powerful methods because it can directly provide the profile of the {alpha} particle energy spectra in a plasma. In the large helical device, PCX using tracer encapsulated solid pellet (TESPEL) has been tried in many hydrogen and helium plasmas, including helium accelerated by using the cyclotron resonance heating. In the PCX, we use the compact neutral particle analyzer without simultaneous mass separation ability. The helium particle measurement can be achieved by the application of voltage in the condenser plate. The scattering of hydrogen particle is carefully considered during the estimation of the helium amount. The radial helium profiles can also be obtained by comparing four TESPEL injection shots with/without higher harmonic fast wave heating and at applied plate voltages for He or H, respectively.

  6. PERFORMANCE OF DIPOLE MAGNETS IN HELIUM II

    E-Print Network [OSTI]

    Althaus, R.

    2010-01-01T23:59:59.000Z

    in Pressurized Superfluid Helium", EX5 40 11th InternationalOF DIPOLE MAGNETS IN HELIUM II R. Althaus, S. Cacpi, W.S.OF DIMLE NMMETS IN HELIUM II* R. Althaus, S. Caspl, W.S.

  7. ELECTRONS ON THE SURFACE OF LIQUID HELIUM

    E-Print Network [OSTI]

    Lambert, David Kay

    2011-01-01T23:59:59.000Z

    ON THE SURFACE OF LIQUID HELIUM David Kay Lambert (Ph. D.ON THE SURFACE OF LIQUID HELIUM David Kay Lambert Materialsthe potential well near a helium surface, The charge density

  8. Regimes Of Helium Burning

    E-Print Network [OSTI]

    F. X. Timmes; J. C. Niemeyer

    2000-05-16T23:59:59.000Z

    The burning regimes encountered by laminar deflagrations and ZND detonations propagating through helium-rich compositions in the presence of buoyancy-driven turbulence are analyzed. Particular attention is given to models of X-ray bursts which start with a thermonuclear runaway on the surface of a neutron star, and the thin shell helium instability of intermediate-mass stars. In the X-ray burst case, turbulent deflagrations propagating in the lateral or radial directions encounter a transition from the distributed regime to the flamlet regime at a density of 10^8 g cm^{-3}. In the radial direction, the purely laminar deflagration width is larger than the pressure scale height for densities smaller than 10^6 g cm^{-3}. Self-sustained laminar deflagrations travelling in the radial direction cannot exist below this density. Similarily, the planar ZND detonation width becomes larger than the pressure scale height at 10^7 g cm^{-3}, suggesting that a steady-state, self-sustained detonations cannot come into existance in the radial direction. In the thin helium shell case, turbulent deflagrations travelling in the lateral or radial directions encounter the distributed regime at densities below 10^7 g cm^{-3}, and the flamelet regime at larger densities. In the radial direction, the purely laminar deflagration width is larger than the pressure scale height for densities smaller than 10^4 g cm^{-3}, indicating that steady-state laminar deflagrations cannot form below this density. The planar ZND detonation width becomes larger than the pressure scale height at 5 10^4 g cm^{-3}, suggesting that steady-state, self-sustained detonations cannot come into existance in the radial direction.

  9. A reassessment of the effects of helium on Charpy impact properties of ferritic/martensitic steels

    SciTech Connect (OSTI)

    Gelles, D.S.; Hamilton, M.L. [Pacific Northwest National Lab., Richland, WA (United States); Hankin, G.L. [Loughborough Univ. (United Kingdom)

    1998-03-01T23:59:59.000Z

    To test the effect of helium on Charpy impact properties of ferritic/martensitic steels, two approaches are reviewed: quantification of results of tests performed on specimens irradiated in reactors with very different neutron spectra, and isotopic tailoring experiments. Data analysis can show that if the differences in reactor response are indeed due to helium effects, then irradiation in a fusion machine at 400 C to 100 dpa and 1000 appm He will result in a ductile to brittle transition temperature shift of over 500 C. However, the response as a function of dose and helium level is unlikely to be simply due to helium based on physical reasoning. Shear punch tests and microstructural examinations also support this conclusion based on irradiated samples of a series of alloys made by adding various isotopes of nickel in order to vary the production of helium during irradiation in HFIR. The addition of nickel at any isotopic balance to the Fe-12Cr base alloy significantly increased the shear yield and maximum strengths of the alloys. However, helium itself, up to 75 appm at over 7 dpa appears to have little effect on the mechanical properties of the alloys. This behavior is instead understood to result from complex precipitation response. The database for effects of helium on embrittlement based on nickel additions is therefore probably misleading and experiments should be redesigned to avoid nickel precipitation.

  10. Helium dilution refrigeration system

    DOE Patents [OSTI]

    Roach, P.R.; Gray, K.E.

    1988-09-13T23:59:59.000Z

    A helium dilution refrigeration system operable over a limited time period, and recyclable for a next period of operation is disclosed. The refrigeration system is compact with a self-contained pumping system and heaters for operation of the system. A mixing chamber contains [sup 3]He and [sup 4]He liquids which are precooled by a coupled container containing [sup 3]He liquid, enabling the phase separation of a [sup 3]He rich liquid phase from a dilute [sup 3]He-[sup 4]He liquid phase which leads to the final stage of a dilution cooling process for obtaining low temperatures. The mixing chamber and a still are coupled by a fluid line and are maintained at substantially the same level with the still cross sectional area being smaller than that of the mixing chamber. This configuration provides maximum cooling power and efficiency by the cooling period ending when the [sup 3]He liquid is depleted from the mixing chamber with the mixing chamber nearly empty of liquid helium, thus avoiding unnecessary and inefficient cooling of a large amount of the dilute [sup 3]He-[sup 4]He liquid phase. 2 figs.

  11. Helium dilution refrigeration system

    DOE Patents [OSTI]

    Roach, Patrick R. (Darien, IL); Gray, Kenneth E. (Naperville, IL)

    1988-01-01T23:59:59.000Z

    A helium dilution refrigeration system operable over a limited time period, and recyclable for a next period of operation. The refrigeration system is compact with a self-contained pumping system and heaters for operation of the system. A mixing chamber contains .sup.3 He and .sup.4 He liquids which are precooled by a coupled container containing .sup.3 He liquid, enabling the phase separation of a .sup.3 He rich liquid phase from a dilute .sup.3 He-.sup.4 He liquid phase which leads to the final stage of a dilution cooling process for obtaining low temperatures. The mixing chamber and a still are coupled by a fluid line and are maintained at substantially the same level with the still cross sectional area being smaller than that of the mixing chamber. This configuration provides maximum cooling power and efficiency by the cooling period ending when the .sup.3 He liquid is depleted from the mixing chamber with the mixing chamber nearly empty of liquid helium, thus avoiding unnecessary and inefficient cooling of a large amount of the dilute .sup.3 He-.sup.4 He liquid phase.

  12. Helium-cooled lithiuim compound suspension blanket concept for ITER

    SciTech Connect (OSTI)

    Gohar, Y.; Baker, C.C.; Attaya, H.; Billone, M.; Clemmer, R.C.; Finn, P.A.; Hassanein, A.; Johnson, C.E.; Majumdar, S.; Mattas, R.F.

    1988-08-01T23:59:59.000Z

    This blanket concept uses a dilute suspension of fine solid breeder particles (Li/sub 2/O, LiAlO/sub 2/, or Li/sub 4/SiO/sub 4/) in a carrier gas (He) as the coolant and the tritium breeding stream. A small fraction of this stream is processed outside the reactor for tritium recovery. The blanket consists of a beryllium multiplier and carbon/steel reflector. A steel clad is used for all materials. A carbon reflector is employed to reduce the beryllium thickness used in the blanket for a specific tritium breeding ratio. The breeder particle size has to exceed few microns (greater than or equal to2 microns) to avoid sticking problems on the cold surfaces of the heat exchanger. The helium gas pressure is in the range of 2 to 3 MPa to carry the blanket and the heat exchanger loop. The solid breeder concentration in the helium stream is 1 to 5 volume percent. A high lithium-6 enrichment is used to produce a high tritium breeding ratio and to reduce the breeder concentration in the helium gas. At a lithium-6 enrichment of 90%, the local tritium breeding ratio is 2.03 based on a one-dimensional poloidal model. The total thickness of the helium stream is only 4 cm out of the 50 cm total blanket thickness. The blanket uses a 35 cm of beryllium for neutron multiplication. A simple multi-layer design is employed where the blanket sector has the helium coolant flowing in the poloidal direction. The blanket concept has several unique advantages which are very beneficial for fusion reactors including ITER. 10 refs., 2 tabs.

  13. Quantum Cavitation: a comparison between superfluid helium-4 and normal liquid helium-3

    E-Print Network [OSTI]

    Caupin, Frédéric

    Quantum Cavitation: a comparison between superfluid helium-4 and normal liquid helium-3 S. Balibar in superfluid helium-4 and in normal liquid helium-3, both theoretically and experimentally. We compare the two by tunneling, to classical cavitation where their nu- cleation is thermally activated. In helium-3, where

  14. Helium-cooled solid breeder blanket for ITER

    SciTech Connect (OSTI)

    Raffray, A.R.; Abdou, M.A.; Chou, P.; Gorbis, Z.; Tillack, M.; Watanabe, Y.; Ying, A.

    1989-03-01T23:59:59.000Z

    This paper summarizes the latest results of a design study of a helium-cooled solid breeder blanket for ITER. Attractive features of this design include the following: (1) There is a significant design margin since only part of the allowable solid breeder temperature window needs to be used. (2) There is an expanding data base available from solid breeder experiments carried out internationally. (3) The solid breeder can be designed to operate at high reactor-relevant temperature, while the helium is kept at moderate temperature and pressure for safety and reliability. In addition, since helium is a gas, it can be run so as to optimize the structure temperature and accommodate long term power variation without incurring any substantial pressure penalty. (4) The use of helium, an inert gas minimizing any chemical reaction and corrosion, in combination with a low activation solid breeder, is a safety advantage. An extensive list of the blanket operating parameters is provided and key factors are discussed.

  15. The consequences of helium production and nickel additions on microstructure development in isotopically tailored ferritic alloys

    SciTech Connect (OSTI)

    Gelles, D.S. [Pacific Northwest National Lab., Richland, WA (United States)

    1999-10-01T23:59:59.000Z

    A series of alloys have been made adding various isotopes of nickel in order to vary the production of helium during irradiation by a two step nuclear reaction in a mixed spectrum reactor. The alloys use a base composition of Fe-12Cr with an addition of 1.5% nickel, either in the form of {sup 60}Ni which produces no helium, {sup 59}Ni which produces helium at a rate of about 10 appm He/dpa, or natural nickel which provides an intermediate level of helium due to delayed development of {sup 59}Ni. Specimens were irradiated in the HFIR at Oak Ridge, TN to 7.5 dpa at 300 and 400 C. Microstructural examinations indicated that nickel additions promote precipitation in all alloys, but the effect appears to be much stronger at 400 C than at 300 C. There is sufficient dose by 7 dpa (and with 2 appm He) to initiate void swelling in ferritic/martensitic alloys. Little difference was found between response from {sup 59}Ni and natural nickel. Also, helium bubble development for high helium generation conditions appeared to be very different at 300 and 400 C. At 300 C, it appeared that high densities of bubbles formed whereas at 400 C, bubbles could not be identified, possibly because of the complexity of the microstructure, but more likely because helium accumulated at precipitate interfaces.

  16. The consequences of helium production on microstructural development in isotopically tailored ferritic alloys

    SciTech Connect (OSTI)

    Gelles, D.S. [Pacific Northwest Lab., Richland, WA (United States)

    1996-10-01T23:59:59.000Z

    A series of alloys have been made adding various isotopes of nickel in order to vary the production of helium during irradiation by a two step nuclear reaction in a mixed spectrum reactor. The alloys use a base composition of Fe-12Cr with an addition of 1.5% nickel, either in the form of {sup 60}Ni which produces no helium, {sup 59}Ni which produces helium at a rate of about 10 appm He/dpa, or natural nickel ({sup Nat}Ni) which provides an intermediate level of helium due to delayed development of {sup 59}Ni. Specimens were irradiated in the HFIR at Oak Ridge, TN to {approx}7 dpa at 300 and 400{degrees}C. Microstructural examinations indicated that nickel additions promote precipitation in all alloys, but the effect appears to be much stronger at 400{degrees}C than at 300{degrees}C. There is sufficient dose by 7 dpa (and with 2 appm He) to initiate void swelling in ferritic/martensitic alloys. Little difference was found between response from {sup 59}Ni and {sup Nat}Ni. Also, helium bubble development for high helium generation conditions appeared to be very different at 300 and 400{degrees}C. At 300{degrees}C, it appeared that high densities of bubbles formed whereas at 400{degrees}C, bubbles could not be identified, possibly because of the complexity of the microstructure, but more likely because helium accumulated at precipitate interfaces.

  17. Crystal orientation effects on helium ion depth distributions and adatom formation processes in plasma-facing tungsten

    SciTech Connect (OSTI)

    Hammond, Karl D. [Department of Nuclear Engineering, University of Tennessee, Knoxville, Tennessee 37996–2300 (United States); Wirth, Brian D., E-mail: bdwirth@utk.edu [Department of Nuclear Engineering, University of Tennessee, Knoxville, Tennessee 37996–2300 (United States); P.O. Box 2008, MS-6003, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831–6003 (United States)

    2014-10-14T23:59:59.000Z

    We present atomistic simulations that show the effect of surface orientation on helium depth distributions and surface feature formation as a result of low-energy helium plasma exposure. We find a pronounced effect of surface orientation on the initial depth of implanted helium ions, as well as a difference in reflection and helium retention across different surface orientations. Our results indicate that single helium interstitials are sufficient to induce the formation of adatom/substitutional helium pairs under certain highly corrugated tungsten surfaces, such as (1 1 1)-orientations, leading to the formation of a relatively concentrated layer of immobile helium immediately below the surface. The energies involved for helium-induced adatom formation on (1 1 1) and (2 1 1) surfaces are exoergic for even a single adatom very close to the surface, while (0 0 1) and (0 1 1) surfaces require two or even three helium atoms in a cluster before a substitutional helium cluster and adatom will form with reasonable probability. This phenomenon results in much higher initial helium retention during helium plasma exposure to (1 1 1) and (2 1 1) tungsten surfaces than is observed for (0 0 1) or (0 1 1) surfaces and is much higher than can be attributed to differences in the initial depth distributions alone. The layer thus formed may serve as nucleation sites for further bubble formation and growth or as a source of material embrittlement or fatigue, which may have implications for the formation of tungsten “fuzz” in plasma-facing divertors for magnetic-confinement nuclear fusion reactors and/or the lifetime of such divertors.

  18. Accelerated Helium and Hydrogen Production in Fe-54 Doped Alloys - Measurements and Calculations for the FIST Experiment

    SciTech Connect (OSTI)

    Greenwood, Lawrence R.; Oliver, Brian M.; Ohnuki, Somei; Shiba, K.; Kohno, Yutaka; Kohyama, Akira; Robertson, J. P.; Meadows, J. W.; Gelles, David S.

    2000-12-01T23:59:59.000Z

    F-82H alloys isotopically enriched in 54Fe up to 86% were irradiated in the High Flux Isotope Reactor (HFIR) to determine the accelerated production of helium and hydrogen due to isotopic effects. Results are compared to calculations using isotopic helium production cross sections from ENDF/B-VI or GNASH and measured neutron spectra. Helium measurements demonstrated an accelerated helium (appm)/dpa ratio of 2.3 after a 1.25-year irradiation, an increase of a factor of 4.3 over natural iron. The accelerated helium production is due to higher helium production cross sections for 54Fe and 55Fe. Alloys doped with 55Fe could achieve helium/dpa ratios up to about 20, well above the fusion reactor ratio of 10. Hydrogen measurements were performed using a newly developed quadrupole mass spectrometer system at PNNL capable of detecting 5-appm hydrogen in milligram-sized irradiated specimens. Calculations predict that hydrogen production will be accelerated by about a factor of 13 over natural iron. However, measurements show that most of this hydrogen is not retained in the samples.

  19. A Torsional Oscillator Study Solid Helium

    E-Print Network [OSTI]

    Sheldon, Nathan D.

    A Torsional Oscillator Study of Solid Helium George Edgar Marcus Nichols Royal Holloway College and Andy Nichols and Alexandra Zuckermann for theirs out of it. #12;Contents 1 Motivation 10 1.1 Helium

  20. Fine structure of helium and light helium-like ions Krzysztof Pachucki and Vladimir A. Yerokhin

    E-Print Network [OSTI]

    Pachucki, Krzysztof

    1 Fine structure of helium and light helium-like ions Krzysztof Pachucki and Vladimir A. Yerokhin Abstract: Calculational results are presented for the fine-structure splitting of the 23 P state of helium and helium-like ions with the nuclear charge Z up to 10. Theoretical predictions are in agreement

  1. 8 2. Helium und Tritium in der Geosphre 2. Helium und Tritium in der Geosphre

    E-Print Network [OSTI]

    Aeschbach-Hertig, Werner

    8 2. Helium und Tritium in der Geosphäre 2. Helium und Tritium in der Geosphäre 2.1. Spezielle Einheiten und Konstanten An dieser Stelle sollen die speziellen für Helium und Tritium verwendeten Einheiten definiert und dazugehörige Umrechnungen angegeben werden. Die Wahl der Werte einiger für Helium und Tritium

  2. Pulsed helium ionization detection system

    DOE Patents [OSTI]

    Ramsey, R.S.; Todd, R.A.

    1985-04-09T23:59:59.000Z

    A helium ionization detection system is provided which produces stable operation of a conventional helium ionization detector while providing improved sensitivity and linearity. Stability is improved by applying pulsed dc supply voltage across the ionization detector, thereby modifying the sampling of the detectors output current. A unique pulse generator is used to supply pulsed dc to the detector which has variable width and interval adjust features that allows up to 500 V to be applied in pulse widths ranging from about 150 nsec to about dc conditions.

  3. Pulsed helium ionization detection system

    DOE Patents [OSTI]

    Ramsey, Roswitha S. (Knoxville, TN); Todd, Richard A. (Knoxville, TN)

    1987-01-01T23:59:59.000Z

    A helium ionization detection system is provided which produces stable operation of a conventional helium ionization detector while providing improved sensitivity and linearity. Stability is improved by applying pulsed dc supply voltage across the ionization detector, thereby modifying the sampling of the detectors output current. A unique pulse generator is used to supply pulsed dc to the detector which has variable width and interval adjust features that allows up to 500 V to be applied in pulse widths ranging from about 150 nsec to about dc conditions.

  4. Phase and density dependence of the delayed annihilation of metastable antiprotonic helium atoms in gas, liquid and solid helium

    E-Print Network [OSTI]

    Widmann, E; Yamazaki, T; Hayano, R S; Iwasaki, M; Nakamura, S N; Tamura, H; Ito, T M; Kawachi, A; Nishida, N; Higemoto, W; Ito, Y; Morita, N; Hartmann, F J; Daniel, H; Von Egidy, T; Schmid, W; Hoffmann, J; Eades, John

    1995-01-01T23:59:59.000Z

    Phase and density dependence of the delayed annihilation of metastable antiprotonic helium atoms in gas, liquid and solid helium

  5. Helium Refrigerator Design for Pulsed Heat Load in Tokamaks

    SciTech Connect (OSTI)

    Kuendig, A.; Schoenfeld, H. [Linde Kryotechnik AG, Dattlikonerstrasse 5, CH-8422 Pfungen (Switzerland)

    2006-04-27T23:59:59.000Z

    Nuclear fusion reactors of the Tokamak type will be operated in a pulsed mode requiring the helium refrigerator to remove periodically large heat loads in time steps of approximately one hour. What are the necessary steps for a refrigerator to cope with such load variations?A series of numerical simulations has been performed indicating the possibility of an active refrigerator control with low exergetic losses. A basic comparison is made between the largest existing refrigerator sizes and the size required to service for example the ITER requirements.

  6. QUANTUM STATISTICS OF METASTABLE LIQUID HELIUM

    E-Print Network [OSTI]

    Caupin, Frédéric

    QUANTUM STATISTICS OF METASTABLE LIQUID HELIUM FR´ED´ERIC CAUPIN AND S´EBASTIEN BALIBAR Laboratoire in the spinodal line of liquid helium 3, for which experimental evidence has been reported. The calculations in the case of superfluid helium 4; we also consider the overpressurized region, and the location

  7. Mining Helium programs with Neon Jurriaan Hage

    E-Print Network [OSTI]

    Utrecht, Universiteit

    Mining Helium programs with Neon Jurriaan Hage Peter van Keeken Department of Information in a first-year functional programming course using the Helium compiler. The mining of such a collection to resolve a type error. 1 #12;1 Introduction and motivation When the Helium compiler for learning Haskell

  8. Characterization of reconnecting vortices in superfluid helium

    E-Print Network [OSTI]

    Texas at Austin. University of

    Characterization of reconnecting vortices in superfluid helium Gregory P. Bewley*, Matthew S experimental observations of reconnection between quantized vortices in superfluid helium. We do so by imaging. reconnection Vorticity in superfluid helium is confined to filaments that are only angstroms in diameter

  9. Circuit Quantum Electrodynamics with Electrons on Helium

    E-Print Network [OSTI]

    Circuit Quantum Electrodynamics with Electrons on Helium A Dissertation Presented to the Faculty Fragner All rights reserved. ii #12;Abstract Circuit Quantum Electrodynamics with Electrons on Helium helium. Such a system represents a solid-state, electrical circuit analog of atomic cavity QED in which

  10. Helium Migration in Iron Christ's College

    E-Print Network [OSTI]

    Cambridge, University of

    Helium Migration in Iron Y. Zhang Christ's College Department of Materials Science and Metallurgy the achievement at all. ii #12;Abstract A theoretical model of helium migration in body centred cubic (BCC)structure irons has been developed using the concept of the effective helium diffusion coeffi- cient

  11. Assessment of Embrittlement of VHTR Structural Alloys in Impure Helium Environments

    SciTech Connect (OSTI)

    Crone, Wendy; Cao, Guoping; Sridhara, Kumar

    2013-05-31T23:59:59.000Z

    The helium coolant in high-temperature reactors inevitably contains low levels of impurities during steady-state operation, primarily consisting of small amounts of H{sub 2}, H{sub 2}O, CH{sub 4}, CO, CO{sub 2}, and N{sub 2} from a variety of sources in the reactor circuit. These impurities are problematic because they can cause significant long-term corrosion in the structural alloys used in the heat exchangers at elevated temperatures. Currently, the primary candidate materials for intermediate heat exchangers are Alloy 617, Haynes 230, Alloy 800H, and Hastelloy X. This project will evaluate the role of impurities in helium coolant on the stress-assisted grain boundary oxidation and creep crack growth in candidate alloys at elevated temperatures. The project team will: • Evaluate stress-assisted grain boundary oxidation and creep crack initiation and crack growth in the temperature range of 500-850°C in a prototypical helium environment. • Evaluate the effects of oxygen partial pressure on stress-assisted grain boundary oxidation and creep crack growth in impure helium at 500°C, 700°C, and 850°C respectively. • Characterize the microstructure of candidate alloys after long-term exposure to an impure helium environment in order to understand the correlation between stress-assisted grain boundary oxidation, creep crack growth, material composition, and impurities in the helium coolant. • Evaluate grain boundary engineering as a method to mitigate stress-assisted grain boundary oxidation and creep crack growth of candidate alloys in impure helium. The maximum primary helium coolant temperature in the high-temperature reactor is expected to be 850-1,000°C.Corrosion may involve oxidation, carburization, or decarburization mechanisms depending on the temperature, oxygen partial pressure, carbon activity, and alloy composition. These corrosion reactions can substantially affect long-term mechanical properties such as crack- growth rate and fracture toughness, creep rupture, and fatigue. Although there are some studies on the effects of impurities in helium coolant on creep rupture and fatigue strength, very little is known about their effects on creep crack initiation and crack growth rate at elevated temperatures.

  12. Cryogenic system with GM cryocooler for krypton, xenon separation from hydrogen-helium purge gas

    SciTech Connect (OSTI)

    Chu, X. X.; Zhang, D. X.; Qian, Y.; Liu, W. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800 (China); Zhang, M. M.; Xu, D. [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190 (China)

    2014-01-29T23:59:59.000Z

    In the thorium molten salt reactor (TMSR), fission products such as krypton, xenon and tritium will be produced continuously in the process of nuclear fission reaction. A cryogenic system with a two stage GM cryocooler was designed to separate Kr, Xe, and H{sub 2} from helium purge gas. The temperatures of two stage heat exchanger condensation tanks were maintained at about 38 K and 4.5 K, respectively. The main fluid parameters of heat transfer were confirmed, and the structural heat exchanger equipment and cold box were designed. Designed concentrations after cryogenic separation of Kr, Xe and H{sub 2} in helium recycle gas are less than 1 ppb.

  13. Confined helium on Lagrange meshes

    E-Print Network [OSTI]

    Baye, Daniel

    2015-01-01T23:59:59.000Z

    The Lagrange-mesh method has the simplicity of a calculation on a mesh and can have the accuracy of a variational method. It is applied to the study of a confined helium atom. Two types of confinement are considered. Soft confinements by potentials are studied in perimetric coordinates. Hard confinement in impenetrable spherical cavities is studied in a system of rescaled perimetric coordinates varying in [0,1] intervals. Energies and mean values of the distances between electrons and between an electron and the helium nucleus are calculated. A high accuracy of 11 to 15 significant figures is obtained with small computing times. Pressures acting on the confined atom are also computed. For sphere radii smaller than 1, their relative accuracies are better than $10^{-10}$. For larger radii up to 10, they progressively decrease to $10^{-3}$, still improving the best literature results.

  14. The Epoch of Helium Reionization

    E-Print Network [OSTI]

    Aaron Sokasian; Tom Abel; Lars. E. Hernquist

    2001-12-14T23:59:59.000Z

    We study the reionization of Helium II by quasars using a numerical approach that combines 3D radiative transfer calculations with cosmological hydrodynamical simulations. Sources producing the ionizing radiation are selected according to an empirical quasar luminosity function and are assigned luminosities according to their intrinsic masses. We present models in which these parameters are varied and examine characteristics of the resultant reionization process that distinguish the various cases. In addition, we extract artificial spectra from the simulations and quantify statistical properties of the spectral features in each model. We find that the most important factor affecting the evolution of He II reionization is the cumulative number of ionizing photons that are produced by the sources. Comparisons between He II opacities measured observationally and those obtained by our analysis reveal that the available ranges in plausible values for the parameters provide enough leeway to provide a satisfactory match. However, one property common to all our calculations is that the epoch of Helium II reionization must have occurred at a redshift between 3 < z < 4. If so, future observational programs will be able to directly trace the details of the ionization history of helium and probe the low density phase of the intergalactic medium during this phase of the evolution of the Universe.

  15. Status of fusion reactor blanket design

    SciTech Connect (OSTI)

    Smith, D.L.; Sze, D.K.

    1986-11-01T23:59:59.000Z

    This paper provides a brief review of the Blanket Comparison and Selection Study (BCSS)/sup 1/ and an overview of more recent fusion reactor blanket design efforts. Specific areas covered include improvements in leading blanket concepts identified in the BCSS, viz., self-cooled liquid metal concepts, helium-cooled solid breeder concepts, and helium-cooled liquid breeder concepts. In addition, a summary of innovative blanket concepts and design features is presented. The key features and critical issues associated with these designs are identified.

  16. Helium in Near Earth Orbit The AMS Collaboration

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Helium in Near Earth Orbit The AMS Collaboration Abstract The helium spectrum from 0.1 to 100 Ge the geomagnetic cutoff a second helium spectrum was observed. In the second he- lium spectra over the energy range ninety percent of the helium was deter- mined to be 3 He (at the 90 % CL). Tracing helium from the second

  17. Low energy electron-enhanced etching of Si(100) in hydrogen/helium direct-current plasma

    E-Print Network [OSTI]

    Dove, Patricia M.

    Low energy electron-enhanced etching of Si(100) in hydrogen/helium direct-current plasma H. P of a dc plasma reactor, and thus receives a large flux of low-energy electrons and hydrogen molecules-0269 Received 7 September 1994; accepted for publication 6 March 1995 Low energy electron-enhanced etching of Si

  18. TESTING OF ACCELERATOR DIPOLES IN PRESSURIZED SUPERFLUID HELIUM

    E-Print Network [OSTI]

    Gilbert, W.S.

    2010-01-01T23:59:59.000Z

    ESD-10: facility. I i_ -i i_ Training in helium II Fig. 6 D-5: facility. Training in helium II .f liIN PRESSURIZED SUPERFLUID HELIUM W.S. G i l b e r t , S. C a

  19. Helium measurements of pore-fluids obtained from SAFOD drillcore

    E-Print Network [OSTI]

    Ali, S.

    2010-01-01T23:59:59.000Z

    the ductile lower crust: Helium isotope trends." ScienceHilton, Izbicki, J.A. (2003). "Helium isotope studies in the2005). "Source and movement of helium in the eastern Morongo

  20. Assessment of next generation nuclear plant intermediate heat exchanger design.

    SciTech Connect (OSTI)

    Majumdar, S.; Moisseytsev, A.; Natesan, K.; Nuclear Engineering Division

    2008-10-17T23:59:59.000Z

    The Next Generation Nuclear Plant (NGNP), which is an advanced high temperature gas reactor (HTGR) concept with emphasis on production of both electricity and hydrogen, involves helium as the coolant and a closed-cycle gas turbine for power generation with a core outlet/gas turbine inlet temperature of 900-1000 C. In the indirect cycle system, an intermediate heat exchanger is used to transfer the heat from primary helium from the core to the secondary fluid, which can be helium, nitrogen/helium mixture, or a molten salt. The system concept for the vary high temperature reactor (VHTR) can be a reactor based on the prismatic block of the GT-MHR developed by a consortium led by General Atomics in the U.S. or based on the PBMR design developed by ESKOM of South Africa and British Nuclear Fuels of U.K. This report has made an assessment on the issues pertaining to the intermediate heat exchanger (IHX) for the NGNP. A detailed thermal hydraulic analysis, using models developed at ANL, was performed to calculate heat transfer, temperature distribution, and pressure drop. Two IHX designs namely, shell and straight tube and compact heat exchangers were considered in an earlier assessment. Helical coil heat exchangers were analyzed in the current report and the results were compared with the performance features of designs from industry. In addition, a comparative analysis is presented between the shell and straight tube, helical, and printed circuit heat exchangers from the standpoint of heat exchanger volume, primary and secondary sides pressure drop, and number of tubes. The IHX being a high temperature component, probably needs to be designed using ASME Code Section III, Subsection NH, assuming that the IHX will be classified as a class 1 component. With input from thermal hydraulic calculations performed at ANL, thermal conduction and stress analyses were performed for the helical heat exchanger design and the results were compared with earlier-developed results on shell and straight tube and printed circuit heat exchangers.

  1. Helium stratification in HD 145792: a new Helium strong star

    E-Print Network [OSTI]

    G. Catanzaro

    2007-11-28T23:59:59.000Z

    In this paper we report on the real nature of the star HD 145792, classified as He weak in {\\it ``The General Catalogue of Ap and Am stars''}. By means of FEROS@ESO1.52m high resolution spectroscopic data, we refined the atmospheric parameters of the star, obtaining: T$_{\\rm eff}$ = 14400 $\\pm$ 400 K, $\\log g$ = 4.06 $\\pm$ 0.08 and $\\xi$ = 0 $^{+0.6}$ km s$^{-1}$. These values resulted always lower than those derived by different authors with pure photometric approaches. Using our values we undertook an abundance analysis with the aim to derive, for the first time, the chemical pattern of the star's atmosphere. For metals a pure LTE synthesis (ATLAS9 and SYNTHE) has been used, while for helium a hybrid approach has been preferred (ATLAS9 and SYNSPEC). The principal result of our study is that HD 145792 belongs to He strong class contrary to the previous classification. Moreover, helium seems to be vertically stratified in the atmosphere, decreasing toward deepest layers. For what that concerns metals abundances, we found the following: overabundance of oxygen, neon, silicon, phosphorus, sulfur and calcium; carbon, nitrogen, magnesium, aluminum, titanium, chromium and nickel are normal, being the discrepancies from the solar values within the experimental errors; iron resulted to be slightly underabundant.

  2. Lessons Learned From Gen I Carbon Dioxide Cooled Reactors

    SciTech Connect (OSTI)

    David E. Shropshire

    2004-04-01T23:59:59.000Z

    This paper provides a review of early gas cooled reactors including the Magnox reactors originating in the United Kingdom and the subsequent development of the Advanced Gas-cooled Reactors (AGR). These early gas cooled reactors shared a common coolant medium, namely carbon dioxide (CO2). A framework of information is provided about these early reactors and identifies unique problems/opportunities associated with use of CO2 as a coolant. Reactor designers successfully rose to these challenges. After years of successful use of the CO2 gas cooled reactors in Europe, the succeeding generation of reactors, called the High Temperature Gas Reactors (HTGR), were designed with Helium gas as the coolant. Again, in the 21st century, with the latest reactor designs under investigation in Generation IV, there is a revived interest in developing Gas Cooled Fast Reactors that use CO2 as the reactor coolant. This paper provides a historical perspective on the 52 CO2 reactors and the reactor programs that developed them. The Magnox and AGR design features and safety characteristics were reviewed, as well as the technologies associated with fuel storage, reprocessing, and disposal. Lessons-learned from these programs are noted to benefit the designs of future generations of gas cooled nuclear reactors.

  3. Helium bubble bursting in tungsten

    SciTech Connect (OSTI)

    Sefta, Faiza [University of California, Berkeley, California 94720 (United States); Juslin, Niklas [University of Tennessee, Knoxville, Tennessee 37996 (United States); Wirth, Brian D., E-mail: bdwirth@utk.edu [University of Tennessee, Oak Ridge National Laboratory, Knoxville, Tennessee 37996 (United States)

    2013-12-28T23:59:59.000Z

    Molecular dynamics simulations have been used to systematically study the pressure evolution and bursting behavior of sub-surface helium bubbles and the resulting tungsten surface morphology. This study specifically investigates how bubble shape and size, temperature, tungsten surface orientation, and ligament thickness above the bubble influence bubble stability and surface evolution. The tungsten surface is roughened by a combination of adatom “islands,” craters, and pinholes. The present study provides insight into the mechanisms and conditions leading to various tungsten topology changes, which we believe are the initial stages of surface evolution leading to the formation of nanoscale fuzz.

  4. Proton transfer in histidine-tryptophan heterodimers embedded in helium droplets

    E-Print Network [OSTI]

    Bellina, Bruno; Kresin, Vitaly V

    2015-01-01T23:59:59.000Z

    We used cold helium droplets as nano-scale reactors to form and ionize, by electron bombardment and charge transfer, aromatic amino acid heterodimers of histidine with tryptophan, methyl-tryptophan, and indole. The molecular interaction occurring through an N-H...N hydrogen bond leads to a proton transfer from the indole group of tryptophan to the imidazole group of histidine in a radical cationic environment.

  5. DESIGN OF EPOXY-FREE SUPERCONDUCTING DIPOLE MAGNETS AND PERFORMANCE IN BOTH HELIUM I AND PRESSURIZED HELIUM II

    E-Print Network [OSTI]

    Taylor, C.

    2010-01-01T23:59:59.000Z

    Exchange I " L ^ v v / / / / > > y^ffHn Helium II cryostatWarren et. al. , "A Pressurized Helium H-Cooled Magnet Testin Pressurized Superfluid Helium", CXS 40 11th International

  6. Thermal hydraulic design of a 2400 MW t?h? direct supercritical CO?-cooled fast reactor

    E-Print Network [OSTI]

    Pope, Michael A. (Michael Alexander)

    2006-01-01T23:59:59.000Z

    The gas cooled fast reactor (GFR) has received new attention as one of the basic concepts selected by the Generation-IV International Forum (GIF) for further investigation. Currently, the reference GFR is a helium-cooled ...

  7. High-Resolution Differential Ion Mobility Separations Using Helium...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Helium-Rich Gases. High-Resolution Differential Ion Mobility Separations Using Helium-Rich Gases. Abstract: Analyses of complex mixtures and characterization of ions increasingly...

  8. Boron-10 Neutron Detectors for Helium-3 Replacement

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Homeland Security & Defense Boron-10 Neutron Detectors for Helium-3 Replacement Boron-10 Neutron Detectors for Helium-3 Replacement As part of the Laboratory's national security...

  9. A Helium Isotope Perspective On The Dixie Valley, Nevada, Hydrothermal...

    Open Energy Info (EERE)

    Helium Isotope Perspective On The Dixie Valley, Nevada, Hydrothermal System Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: A Helium Isotope...

  10. Differential Ion Mobility Separations in up to 100% Helium Using...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    in up to 100% Helium Using Microchips. Differential Ion Mobility Separations in up to 100% Helium Using Microchips. Abstract: The performance of differential IMS (FAIMS) analyzers...

  11. Helium Migration Mechanisms in Polycrystalline Uranium Dioxide

    SciTech Connect (OSTI)

    Martin, Guillaume; Desgardin, Pierre; Sauvage, Thierry; Barthe, Marie-France [CERI, CNRS, 3 A rue de la Ferollerie, ORLEANS, 45071 (France); Garcia, Philippe; Carlot, Gaelle [DEN/DEC/SESC/LLCC, CEA Cadarache, Saint Paul Lez Durance, 13108 (France)

    2007-07-01T23:59:59.000Z

    This study aims at identifying the release mechanisms of helium in uranium dioxide. Two sets of polycrystalline UO{sub 2} sintered samples presenting different microstructures were implanted with {sup 3}He ions at concentrations in the region of 0.1 at.%. Changes in helium concentrations were monitored using two Nuclear Reaction Analysis (NRA) techniques based on the {sup 3}He(d,{alpha}){sup 1}H reaction. {sup 3}He release is measured in-situ during sample annealing at temperatures ranging between 700 deg. C and 1000 deg. C. Accurate helium depth profiles are generated after each annealing stage. Results that provide data for further understanding helium release mechanisms are discussed. It is found that helium diffusion appears to be enhanced above 900 deg. C in the vicinity of grain boundaries possibly as a result of the presence of defects. (authors)

  12. Helium-Cooled Refractory Alloys First Wall and Blanket Evaluation

    SciTech Connect (OSTI)

    Wong, C.P.C.; Nygren, R.E.; Baxi, C.B.; Fogarty, P.; Ghoniem, N.; Khater, H.; McCarthy, K.; Merrill, B.; Nelson, B.; Reis, E.E.; Sharafat, S.; Schleicher, R.; Sze, D.K.; Ulrickson, M.; Willms, S.; Youssef, M.; Zinkel, S.

    1999-08-01T23:59:59.000Z

    Under the APEX program the He-cooled system design task is to evaluate and recommend high power density refractory alloy first wall and blanket designs and to recommend and initiate tests to address critical issues. We completed the preliminary design of a helium-cooled, W-5Re alloy, lithium breeder design and the results are reported in this paper. Many areas of the design were assessed, including material selection, helium impurity control, and mechanical, nuclear and thermal hydraulics design, and waste disposal, tritium and safety design. System study results show that at a closed cycle gas turbine (CCGT) gross thermal efficiency of 57.5%, a superconducting coil tokamak reactor, with an aspect ratio of 4, and an output power of 2 GWe, can be projected to have a cost of electricity at 54.6 mill/kWh. Critical issues were identified and we plan to continue the design on some of the critical issues during the next phase of the APEX design study.

  13. Fusion reactor high vacuum pumping: Charcoal cryosorber tritium exposure results

    SciTech Connect (OSTI)

    Sedgley, D.W.; Walthers, C.R.; Jenkins, E.M. (Grumman Aerospace Corp., Bethpage, NY (United States))

    1991-01-01T23:59:59.000Z

    Recent experiments, have shown the practically of using activated charcoal (coconut charcoal) at 4{degrees}K to pump helium and hydrogen isotopes for a fusion reactor. Both speed and capacity for deuterium/helium and tritium/helium-3 mixtures were shown to be satisfactory. The long term effects of tritium on the charcoal/cement system developed by Grumman and LLNL were not known and a program was undertaken to see what, if any, effect long term tritium exposure has on the cryosorber. Several charcoal on aluminum test samples were subjected to six months exposure of tritium at approximately 77{degrees}K. The tritium was scanned several times with a residual gas analyzer and the speed-capacity performance of the samples was measured before, approximately half way through and after the exposure. Modest effects were noted which would not seriously restrict charcoal's use as a cryosorber for fusion reactor high vacuum pumping applications. 4 refs., 8 figs.

  14. Quasi-free electron energy in near critical point helium

    E-Print Network [OSTI]

    Findley, Gary L.

    Quasi-free electron energy in near critical point helium Yevgeniy Lushtak a,b , Samantha B, Monroe, LA 71209 Abstract We present for the first time the quasi-free electron energy V0() in helium from low density to the density of the triple point liquid (gaseous helium/liquid helium I

  15. Long range forces between atomic impurities in liquid helium

    E-Print Network [OSTI]

    Long range forces between atomic impurities in liquid helium J. Dupont-Roc Laboratoire Kastler in a polarizable medium. We show that atomic impurities in liquid helium may indeed realize repulsive forces embedded in liquid helium, super uid or not. Solid helium have also been used. Successful theoretical

  16. Helium refrigeration considerations for cryomodule design

    SciTech Connect (OSTI)

    Ganni, V.; Knudsen, P. [Thomas Jefferson National Accelerator Facility (JLab), Newport News, VA 23606 (United States)

    2014-01-29T23:59:59.000Z

    Many of the present day accelerators are based on superconducting radio frequency (SRF) cavities, packaged in cryo-modules (CM), which depend on helium refrigeration at sub-atmospheric pressures, nominally 2 K. These specialized helium refrigeration systems are quite cost intensive to produce and operate. Particularly as there is typically no work extraction below the 4.5-K supply, it is important that the exergy loss between this temperature level and the CM load temperature(s) be minimized by the process configuration choices. This paper will present, compare and discuss several possible helium distribution process arrangements to support the CM loads.

  17. Equation of state of metallic helium

    SciTech Connect (OSTI)

    Shvets, V. T., E-mail: tarval@breezein.net [Odessa State Academy of Refrigeration (Ukraine)

    2013-01-15T23:59:59.000Z

    The effective ion-ion interaction, free energy, pressure, and electric resistance of metallic liquid helium have been calculated in wide density and temperature ranges using perturbation theory in the electron-ion interaction potential. In the case of conduction electrons, the exchange interaction has been taken into account in the random-phase approximation and correlations have been taken into account in the local-field approximation. The solid-sphere model has been used for the nuclear subsystem. The diameter of these spheres is the only parameter of this theory. The diameter and density of the system at which the transition of helium from the singly ionized to doubly ionized state occurs have been estimated by analyzing the pair effective interaction between helium atoms. The case of doubly ionized helium atoms has been considered. Terms up to the third order of perturbation theory have been taken into account in the numerical calculations. The contribution of the third-order term is significant in all cases. The electric resistance and its temperature dependence for metallic helium are characteristic of simple divalent metals in the liquid state. The thermodynamic parameters-temperature and pressure densities-are within the ranges characteristic of the central regions of giant planets. This makes it possible to assume the existence of helium in the metallic state within the solar system.

  18. First-principles calculations of the stability and incorporation of helium, xenon and krypton in uranium

    SciTech Connect (OSTI)

    B. Beeler; B. Good; S. Rashkeev; M. Baskes; M. Okuniewski

    2012-06-01T23:59:59.000Z

    While metallic fuels have a long history of reactor use, their fundamental physical and thermodynamic properties are not well understood. Many metallic nuclear fuels are body-centered cubic alloys of uranium that swell under fission conditions, creating fission product gases such as helium, xenon and krypton. In this paper, helium, xenon, and krypton point defects are investigated in the a and ? phases of metallic uranium using first principles calculations. A density functional theory (DFT) framework is utilized with projector augmented-wave (PAW) pseudopotentials. Formation and incorporation energies of He, Xe, and Kr are calculated at various defect positions for the prediction of fission gas behavior in uranium. In most cases, defect energies follow a size effect, with helium incorporation and formation energies being the smallest. The most likely position for the larger Xe and Kr atoms in uranium is the substitutional site. Helium atoms are likely to be found in a wide variety of defect positions due to the comparable formation energies of all defect configurations analyzed. This is the first detailed study of the stability and incorporation of fission gases in uranium.

  19. Measurement of Helium-3/Helium-4 Ratios in Soil Gas at the 618-11 Burial Ground

    SciTech Connect (OSTI)

    Olsen, Khris B.; Dresel, P Evan; Evans, John C.

    2001-10-31T23:59:59.000Z

    Seventy soil gas-sampling points were installed around the perimeter of the 618-11 Burial Ground, approximately 400 feet downgradient of well 699-13-3A, and in four transects downgradient of the burial ground to a maximum distance of 3,100 feet. Soil gas samples were collected and analyzed for helium-3/helium-4 ratios from these 70 points. Helium-3/helium-4 ratios determined from the soil gas sampling points showed significant enrichments, relative to ambient air helium-3 concentrations. The highest concentrations were located along the northern perimeter of the burial ground. Helium-3/helium-4 ratios (normalized to the abundances in ambient air) ranged from 1.0 to 62 around the burial ground. The helium-3/helium-4 ratios from the 4 transect downgradient of the burial ground ranged from 0.988 to 1.68. The helium-3/helium-4 ratios from around the burial ground suggest there is a vadose zone source of tritium along the north side of the burial ground. This vadose zone source is likely the source of tritium in the groundwater. The helium-3/helium-4 ratios also suggest the groundwater plume is traveling east-northeast from the burial ground and the highest groundwater tritium value may be to the north of well 699-13-3A. Finally, there appears to be no immediately upgradient sources of tritium impacting the burial ground since all the upgradient helium-3/helium-4 ratios are approximately 1.0.

  20. The components for a quantum computer based on surface state electrons on liquid helium

    E-Print Network [OSTI]

    Naberhuis, Brian Patrick

    2007-01-01T23:59:59.000Z

    Electrons on Helium . . . . . . . . . . . . . . . . . 1.5.1calculating the stability of electrons on the helium poolNanoscale Posts . . 3.4.2 Helium Pool . . . . Wire Chapter 4

  1. Helium and Carbon Isotope Systematics in Groundwaters along the Southern San Andreas Fault System /

    E-Print Network [OSTI]

    Evans, Tyler John

    2013-01-01T23:59:59.000Z

    P. , & Newton, R. (2010). Low helium flux from the mantlefrom simulations of oceanic helium isotope data. Earth andJ. , & Baur, H. (1995). Helium, neon, and argon systematics

  2. Cavity morphology in a Ni based superalloy under heavy ion irradiation with cold pre-injected helium. I

    SciTech Connect (OSTI)

    Zhang, He; Yao, Zhongwen, E-mail: yaoz@me.queensu.ca; Daymond, Mark R. [Department of Mechanical and Materials Engineering, Queen's University Kingston, Ontario K7L 3N6 (Canada); Kirk, Marquis A. [Material Science Division, Argonne National Laboratory Argonne, Illinois 60439 (United States)

    2014-03-14T23:59:59.000Z

    In order to understand radiation damage in the nickel based superalloy Inconel X-750 in thermal reactors, where (n, ?) transmutation reaction also occurred in addition to fast neutron induced atomic displacement, heavy ion (1?MeV Kr{sup 2+}) irradiation with pre-injected helium was performed under in-situ observations of an intermediate voltage electron microscope at Argonne National Laboratory. By comparing to our previous studies using 1?MeV Kr{sup 2+} irradiation solely, the pre-injected helium was found to be essential in cavity nucleation. Cavities started to be visible after Kr{sup 2+} irradiation to 2.7 dpa at ?200?°C in samples containing 200 appm, 1000 appm, and 5000 appm helium, respectively, but not at lower temperatures. The cavity growth was observed during the continuous irradiation. Cavity formation appeared along with a reduced number density of stacking fault tetrahedra, vacancy type defects. With higher pre-injected helium amount, a higher density of smaller cavities was observed. This is considered to be the result of local trapping effect of helium which disperses vacancies. The average cavity size increases with increasing irradiation temperatures; the density reduced; and the distribution of cavities became heterogeneous at elevated temperatures. In contrast to previous characterization of in-reactor neutron irradiated Inconel X-750, no obvious cavity sink to grain boundaries and phase boundaries was found even at high doses and elevated temperatures. MC-type carbides were observed as strong sources for agglomeration of cavities due to their enhanced trapping strength of helium and vacancies.

  3. Accumulation and extraction of ultracold neutrons from a superfluid helium converter coated with fluorinated grease

    E-Print Network [OSTI]

    O. Zimmer; P. Schmidt-Wellenburg; M. Assmann; M. Fertl; J. Klenke; S. Mironov; H. -F. Wirth; B. van den Brandt

    2008-01-31T23:59:59.000Z

    We report experiments on the production of ultracold neutrons (UCN) in a converter of superfluid helium coated with fluorinated grease. We employed our technique of window-free extraction of accumulated UCN from the helium, in which they were produced by downscattering neutrons of a cold beam from the Munich research reactor. The time constant for UCN passage through the same extraction aperture as in a previous experiment was a factor two shorter, despite a lower mean velocity of the accumulated UCN in the present experiments. A time-of-flight measurement of the cold neutron spectrum incident on the converter allowed us to estimate the multi-phonon contribution to the UCN production. The UCN production rate inferred from two methods agrees with the theoretical expectation.

  4. Development of a test rig for a helium twin-screw compressor

    SciTech Connect (OSTI)

    Wang, B. M.; Hu, Z. J. [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Zhang, P. [School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Li, Q. [State Key Laboratory of Technologies in Space Cryogenic Propellant(Institute of Physics and Chemistry, Chinese Academy of Sciences), Beijing 100190 (China)

    2014-01-29T23:59:59.000Z

    A large helium cryogenic system is being developed for use in great science projects, such as the International Thermonuclear Experimental Reactor (ITER), Large Helical Device (LHD), and the Experimental Advanced Superconducting Tokamak (EAST). In this cryogenic system, a twin-screw compressor is a key component. Therefore, it is necessary to obtain the compressor performance. To obtain the performance characteristics, a test rig for the compressor has been built. All the important performance parameters, including adiabatic efficiency, volumetric efficiency, oil injection characteristic, and noise characteristic can be acquired with the rig when sensors are installed in the test system. With the test performance, the helium twin-screw compressor can be evaluated. Using these results, the design of the compressor can be improved.

  5. Muon transfer from hydrogen to helium

    SciTech Connect (OSTI)

    Bystritskii, V.M.; Dzhelepov, V.P.; Petrukhin, V.I.; Rudenko, A.I.; Suvorov, V.M.; Filchenkov, V.V.; Khovanskii, N.N.; Khomenko, B.A.

    1983-04-01T23:59:59.000Z

    It is found that ..mu../sup -/ mesons stopped in a gas mixture of hydrogen, helium, and xenon (hydrogen pressure about 20 atmospheres, helium and xenon densities relative to hydrogen 0.05--2 and approx.10/sup -4/ respectively) are transferred from the p..mu.. atoms in the ground state to helium atoms at a rate lambda/sub He/ = (3.6 +- 1.0)x10/sup 8/ sec/sup -1/. The result is in good agreement with the calculations in which a novel mesic-molecular mechanism of p..mu..-atom charge exchange with helium nuclei is taken into account. The dependence of the probability for p..mu..-atom formation in the ground state on the helium density is measured. An analysis of this dependence and a comparison of it with the corresponding data for ..pi../sup -/ mesons indicate that muons can also be transferred from excited levels of p..mu.. atoms at a rate higher than in the case of p..pi.. atoms (transfer constant ..lambda../sub ..mu../ = 3.8 +- 0.3 compared with ..lambda../sub ..pi../ = 1.84 +- 0.09).

  6. Dependence of helium transport on plasma current and ELM frequency in H-mode discharges in DIII-D

    SciTech Connect (OSTI)

    Wade, M.R. [Oak Ridge Inst. for Science and Education, TN (United States); Hillis, D.L.; Hogan, J.T. [Oak Ridge National Lab., TN (United States); Finkenthal, D.F. [California Univ., Berkeley, CA (United States); West, W.P.; Burrell, K.H.; Seraydarian, R.P. [General Atomics, San Diego, CA (United States)

    1993-05-01T23:59:59.000Z

    The removal of helium (He) ash from the plasma core with high efficiency to prevent dilution of the D-T fuel mixture is of utmost importance for future fusion devices, such as the International Thermonuclear Experimental Reactor (ITER). A variety of measurements in L-mode conditions have shown that the intrinsic level of helium transport from the core to the edge may be sufficient to prevent sufficient dilution (i.e., {tau}{sub He} /{tau}{sub E} < 5). Preliminary measurements in biased-induced, limited H-mode discharges in TEXTOR suggest that the intrinsic helium transport properties may not be as favorable. If this trend is shown also in diverted H-mode plasmas, then scenarios based on ELMing H-modes would be less desirable. To further establish the database on helium transport in H-mode conditions, recent studies on the DIII-D tokamak have focused on determining helium transport properties in H-mode conditions and the dependence of these properties on plasma current and ELM frequency.

  7. Repair welding of fusion reactor components. Final technical report

    SciTech Connect (OSTI)

    Chin, B.A.; Wang, C.A.

    1997-09-30T23:59:59.000Z

    The exposure of metallic materials, such as structural components of the first wall and blanket of a fusion reactor, to neutron irradiation will induce changes in both the material composition and microstructure. Along with these changes can come a corresponding deterioration in mechanical properties resulting in premature failure. It is, therefore, essential to expect that the repair and replacement of the degraded components will be necessary. Such repairs may require the joining of irradiated materials through the use of fusion welding processes. The present ITER (International Thermonuclear Experimental Reactor) conceptual design is anticipated to have about 5 km of longitudinal welds and ten thousand pipe butt welds in the blanket structure. A recent study by Buende et al. predict that a failure is most likely to occur in a weld. The study is based on data from other large structures, particularly nuclear reactors. The data used also appear to be consistent with the operating experience of the Fast Flux Test Facility (FFTF). This reactor has a fuel pin area comparable with the area of the ITER first wall and has experienced one unanticipated fuel pin failure after two years of operation. The repair of irradiated structures using fusion welding will be difficult due to the entrapped helium. Due to its extremely low solubility in metals, helium will diffuse and agglomerate to form helium bubbles after being trapped at point defects, dislocations, and grain boundaries. Welding of neutron-irradiated type 304 stainless steels has been reported with varying degree of heat-affected zone cracking (HAZ). The objectives of this study were to determine the threshold helium concentrations required to cause HAZ cracking and to investigate techniques that might be used to eliminate the HAZ cracking in welding of helium-containing materials.

  8. Helium corona-assisted air discharge

    SciTech Connect (OSTI)

    Jiang Nan; Gao Lei; Ji Ailing; Cao Zexian [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2011-10-15T23:59:59.000Z

    Operation of atmospheric discharge of electronegative gases including air at low voltages yet without consuming any inert gas will enormously promote the application of non-thermal plasmas. By taking advantage of the low onset voltage for helium corona, air discharge was successfully launched at much reduced voltages with a needle-plate system partly contained in a helium-filled glass bulb--for a needle-plate distance of 12 mm, 1.0 kV suffices. Ultraviolet emission from helium corona facilitates the discharging of air, and the discharge current manifests distinct features such as relatively broad Trichel pulses in both half periods. This design allows safe and economic implementation of atmospheric discharge of electronegative gases, which will find a broad palette of applications in surface modification, plasma medicine and gas treatment, etc.

  9. A New Wide Range Equation of State for Helium-4 

    E-Print Network [OSTI]

    Ortiz Vega, Diego O

    2013-08-01T23:59:59.000Z

    chemical inertness makes it a safer option. Helium replaced hydrogen for blimps in the 1930s after a number of tragic accidents involving hydrogen- filled airships. Helium is used in blimps for advertising, to detect low-flying cruise missiles...

  10. Study on Off-Design Steady State Performances of Helium Gas Turbo-compressor for HTGR-GT

    SciTech Connect (OSTI)

    Qisen Ren; Xiaoyong Yang; Zhiyong Huang; Jie Wang [Tsinghua University, Beijing, 100084 (China)

    2006-07-01T23:59:59.000Z

    The high temperature gas-cooled reactor (HTGR) coupled with direct gas turbine cycle is a promising concept in the future of nuclear power development. Both helium gas turbine and compressor are key components in the cycle. Under normal conditions, the mode of power adjustment is to control total helium mass in the primary loop using gas storage vessels. Meanwhile, thermal power of reactor core is regulated. This article analyzes off-design performances of helium gas turbine and compressors for high temperature gas-cooled reactor with gas turbine cycle (HTGR-GT) at steady state level of electric power adjustment. Moreover, performances of the cycle were simply discussed. Results show that the expansion ratio of turbine decreases as electric power reduces but the compression ratios of compressors increase, efficiencies of both turbine and compressors decrease to some extent. Thermal power does not vary consistently with electric power, the difference between these two powers increases as electric power reduces. As a result of much thermal energy dissipated in the temperature modulator set at core inlet, thermal efficiency of the cycle has a widely reduction under partial load conditions. (authors)

  11. Quantum mechanicallycomplete measurements in electron impact excitation of helium

    E-Print Network [OSTI]

    Quantum mechanicallycomplete measurements in electron impact excitation of helium Andrew G. Mikosza, Nedlands, Perth. 6907, Australia. Abstract. A complete quantum description of the 3! D state of helium, with the Convergent Close Coupling (CCC) calculations. Previous data for helium at 40eV incident electrons

  12. Helium fine structure theory for determination of Krzysztof Pachucki

    E-Print Network [OSTI]

    Pachucki, Krzysztof

    Helium fine structure theory for determination of Krzysztof Pachucki Institute of Theoretical in the calculation of helium fine-structure splitting of the 23 PJ states, based on the quantum electrodynamic theory by comparison with all experimental results for light helium-like ions and with the known large nuclear charge

  13. Helium in confinement: the filling A Neutron Scattering investigation.

    E-Print Network [OSTI]

    Glyde, Henry R.

    Helium in confinement: the filling parameter. A Neutron Scattering investigation. Francesco Albergamo Institut Laue-Langevin, France Helium in confinement: the filling parameter. ­ p.1/13 #12;outline introduction and motivation Helium in confinement: the filling parameter. ­ p.2/13 #12;outline introduction

  14. RESEARCH ARTICLE Particles for tracing turbulent liquid helium

    E-Print Network [OSTI]

    Lathrop, Daniel P.

    RESEARCH ARTICLE Particles for tracing turbulent liquid helium Gregory P. Bewley Æ K. R of local flow velocities in turbulent liquid helium, using tracer particles. We survey and evaluate, we note that cryogenic helium is attractive for experimental studies because its kinematic viscosity

  15. Fluid helium at conditions of giant planetary interiors Lars Stixrude*

    E-Print Network [OSTI]

    Stixrude, Lars

    Fluid helium at conditions of giant planetary interiors Lars Stixrude* and Raymond Jeanloz-abundant chemical element in the universe, helium makes up a large fraction of giant gaseous planets, includ- ing simulations, we find that fluid helium undergoes temperature-induced metallization at high pressures

  16. Classical Helium Atom with Radiation Reaction G. Camelio,1

    E-Print Network [OSTI]

    Carati, Andrea

    Classical Helium Atom with Radiation Reaction G. Camelio,1 A. Carati,2 and L. Galgani2 1) Universit November 2011) We study a classical model of Helium atom in which, in addition to the Coulomb forces be singular with respect to that of Lebesgue. PACS numbers: 05.45.-a, 41.60.-m Keywords: classical Helium atom

  17. RECENT ADVANCES IN HEAT TRANSFER TO HELIUM 1

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    509 RECENT ADVANCES IN HEAT TRANSFER TO HELIUM 1 C. JOHANNES Service de Recherches Appliquées, L'hélium hypercritique. Abstract. - Conditions of thermal exchange in helium 1 are reviewed. Pool boiling thermosi- phon are given. Use of hypercritical helium. REVUE DE PHYSIQUE APPLIQU�E TOME 6, D�CEMBRE 1971, PAGE Introduction

  18. Decommissioning the UHTREX Reactor Facility at Los Alamos, New Mexico

    SciTech Connect (OSTI)

    Salazar, M.; Elder, J.

    1992-08-01T23:59:59.000Z

    The Ultra-High Temperature Reactor Experiment (UHTREX) facility was constructed in the late 1960s to advance high-temperature and gas-cooled reactor technology. The 3-MW reactor was graphite moderated and helium cooled and used 93% enriched uranium as its fuel. The reactor was run for approximately one year and was shut down in February 1970. The decommissioning of the facility involved removing the reactor and its associated components. This document details planning for the decommissioning operations which included characterizing the facility, estimating the costs of decommissioning, preparing environmental documentation, establishing a system to track costs and work progress, and preplanning to correct health and safety concerns in the facility. Work to decommission the facility began in 1988 and was completed in September 1990 at a cost of $2.9 million. The facility was released to Department of Energy for other uses in its Los Alamos program.

  19. Nuclear reactor engineering

    SciTech Connect (OSTI)

    Glasstone, S.; Sesonske, A.

    1981-01-01T23:59:59.000Z

    Chapters are presented concerning energy from nuclear fission; nuclear reactions and radiations; diffusion and slowing-down of neutrons; principles of reactor analysis; nuclear reactor kinetics and control; energy removal; non-fuel reactor materials; the reactor fuel system; radiation protection and environmental effects; nuclear reactor shielding; nuclear reactor safety; and power reactor systems.

  20. Aberration-corrected X-ray spectrum imaging and Fresnel contrast to differentiate nanoclusters and cavities in helium-irradiated alloy 14YWT

    SciTech Connect (OSTI)

    Miller, Michael K [ORNL] [ORNL; Parish, Chad M [ORNL] [ORNL

    2014-01-01T23:59:59.000Z

    Helium accumulation negatively impacts structural materials used in neutron-irradiated environments, such as fission and fusion reactors. Next-generation fission and fusion reactors will require structural materials, such as steels, resistant to large neutron doses yet see service temperatures in the range most affected by helium embrittlement. Previous work has indicated the difficulty of experimentally differentiating nanometer-sized helium bubbles from the Ti-Y-O rich nanoclustsers (NCs) in radiation-tolerant nanostructured ferritic alloys (NFAs). Because the NCs are expected to sequester helium away from grain boundaries and reduce embrittlement, experimental methods to study simultaneously the NC and bubble populations are needed. In this study, aberration-corrected scanning transmission electron microscopy (STEM) results combining high-collection-efficiency X-ray spectrum images (SIs), multivariate statistical analysis (MVSA), and Fresnel-contrast bright-field STEM imaging have been used for such a purpose. Results indicate that Fresnel-contrast imaging, with careful attention to TEM-STEM reciprocity, differentiates bubbles from NCs, and MVSA of X-ray SIs unambiguously identifies NCs. Therefore, combined Fresnel-contrast STEM and X-ray SI is an effective STEM-based method to characterize helium-bearing NFAs.

  1. DETERMINATION DE LA FONCTION DE DISTRIBUTION DE L'ENERGIE ELECTRONIQUE DANS DES COLONNES POSITIVES D'HELIUM ET D'HELIUM-ARGON

    E-Print Network [OSTI]

    Boyer, Edmond

    D'HELIUM ET D'HELIUM-ARGON P. Davy P. Rabache Laboratoire de Physique Electronique, Universite de) have been determined in helium, and helium-argon positiv columns. Between q 06 and q 3 torr, for currents varying between 25 and 400mA, the EDF in helium i s a Maxwell one with a lack of fast electrons

  2. HELIUM COMPRESSOR MONITORING SYSTEM Donna Kubik

    E-Print Network [OSTI]

    HELIUM COMPRESSOR MONITORING SYSTEM Donna Kubik Arecibo Observatory #12;1 CONTENTS 1. Design goals 3 1.1 Features of the compressor monitoring system 4 2. EDAS: The basis of data acquisition 5 2 Compressor #1 Connectors Compressor #2 Connectors Compressor #3 Connectors Compressor #4 Connectors

  3. The Neon DSEL for mining Helium programs

    E-Print Network [OSTI]

    Utrecht, Universiteit

    studies We consider three case studies to illustrate how Neon can be used to data mine the collectionThe Neon DSEL for mining Helium programs Jurriaan Hage Peter van Keeken Department of Information and Computing Sciences, Utrecht University Technical Report UU-CS-2007-023 www.cs.uu.nl ISSN: 0924-3275 #12

  4. Helium-cooled, FLiBe-breeder, beryllium-multiplier blanket for MINIMARS

    SciTech Connect (OSTI)

    Moir, R.W.; Lee, J.D.

    1986-06-01T23:59:59.000Z

    We adapted the helium-cooled, FLiBe-breeder blanket to the commercial tandem-mirror fusion-reactor design, MINIMARS. Vanadium was used to achieve high performance from the high-energy-release neutron-capture reactions and from the high-temperature operation permitted by the refractory property of the material, which increases the conversion efficiency and decreases the helium-pumping power. Although this blanket had the highest performance among the MINIMARS blankets designs, measured by Mn/sub th/ (blanket energy multiplication times thermal conversion efficiency), it had a cost of electricity (COE) 18% higher than the University of Wisconsin (UW) blanket design (42.5 vs 35.9 mills/kW.h). This increased cost was due to using higher-cost blanket materials (beryllium and vanadium) and a thicker blanket, which resulted in higher-cost central-cell magnets and the need for more blanket materials. Apparently, the high efficiency does not substantially affect the COE. Therefore, in the future, we recommend lowering the helium temperature so that ferritic steel can be used. This will result in a lower-cost blanket, which may compensate for the lower performance resulting from lower efficiency.

  5. Bioconversion reactor

    DOE Patents [OSTI]

    McCarty, Perry L. (Stanford, CA); Bachmann, Andre (Palo Alto, CA)

    1992-01-01T23:59:59.000Z

    A bioconversion reactor for the anaerobic fermentation of organic material. The bioconversion reactor comprises a shell enclosing a predetermined volume, an inlet port through which a liquid stream containing organic materials enters the shell, and an outlet port through which the stream exits the shell. A series of vertical and spaced-apart baffles are positioned within the shell to force the stream to flow under and over them as it passes from the inlet to the outlet port. The baffles present a barrier to the microorganisms within the shell causing them to rise and fall within the reactor but to move horizontally at a very slow rate. Treatment detention times of one day or less are possible.

  6. Catalytic reactor

    DOE Patents [OSTI]

    Aaron, Timothy Mark (East Amherst, NY); Shah, Minish Mahendra (East Amherst, NY); Jibb, Richard John (Amherst, NY)

    2009-03-10T23:59:59.000Z

    A catalytic reactor is provided with one or more reaction zones each formed of set(s) of reaction tubes containing a catalyst to promote chemical reaction within a feed stream. The reaction tubes are of helical configuration and are arranged in a substantially coaxial relationship to form a coil-like structure. Heat exchangers and steam generators can be formed by similar tube arrangements. In such manner, the reaction zone(s) and hence, the reactor is compact and the pressure drop through components is minimized. The resultant compact form has improved heat transfer characteristics and is far easier to thermally insulate than prior art compact reactor designs. Various chemical reactions are contemplated within such coil-like structures such that as steam methane reforming followed by water-gas shift. The coil-like structures can be housed within annular chambers of a cylindrical housing that also provide flow paths for various heat exchange fluids to heat and cool components.

  7. Measurement of Helium-3/Helium-4 Ratios in Soil Gas at the 618-11 Burial Ground

    SciTech Connect (OSTI)

    Olsen, Khris B; Dresel, P Evan; Evans, John C

    2001-10-31T23:59:59.000Z

    Seventy soil gas-sampling points were installed around the perimeter of the 618-11 Burial Ground, approximately 400 feet downgradient of well 699-13-3A, and in four transects downgradient of the burial ground to a maximum distance of 3,100 feet. Soil gas samples were collected and analyzed for helium-3/helium-4 ratios from these 70 points. Helium-3/helium-4 ratios determined from the soil gas sampling points showed significant enrichments, relative to ambient air helium-3 concentrations. The highest concentrations were located along the northern perimeter of the burial ground. Helium-3/helium-4 ratios (normalized to the abundances in ambient air) ranged from 1.0 to 62 around the burial ground. The helium-3/helium-4 ratios from the 4 transect downgradient of the burial ground ranged from 0.988 to 1.68. The helium-3/helium-4 ratios from around the burial ground suggest there is a vadose zone source of tritium along the north side of the burial ground.

  8. Design of a helium-cooled molten salt fusion breeder

    SciTech Connect (OSTI)

    Moir, R.W.; Lee, J.D.; Fulton, F.J.; Huegel, F.; Neef, W.S. Jr.; Sherwood, A.E.; Berwald, D.H.; Whitley, R.H.; Wong, C.P.C.; DeVan, J.H.

    1985-02-01T23:59:59.000Z

    A new conceptual blanket design for a fusion reactor produces fissile material for fission power plants. Fission is suppressed by using beryllium, rather than uranium, to multiply neutrons and also by minimizing the fissile inventory. The molten-salt breeding media (LiF + BeF/sub 2/ + TghF/sub 4/) is circulated through the blanket and on to the online processing system where /sup 233/U and tritium are continuously removed. Helium cools the blanket including the steel pipes containing the molten salt. Austenitic steel was chosen because of its ease of fabrication, adequate radiation-damage lifetime, and low corrosion rate by molten salt. We estimate the breeder, having 3000 MW of fusion power, produces 6400 kg of /sup 233/U per year, which is enough to provide make up for 20 GWe of LWR per year (or 14 LWR plants of 4440 MWt) or twice that many HTGRs or CANDUs. Safety is enhanced because the afterheat is low and the blanket materials do not react with air or water. The fusion breeder based on a pre-MARS tandem mirror is estimated to cost $4.9B or 2.35 times an LWR of the same power. The estimated present value cost of the /sup 2/anumber/sup 3/U produced is $40/g if utility financed or $16/g if government financed.

  9. Neutronic reactor

    DOE Patents [OSTI]

    Wende, Charles W. J. (Augusta, GA); Babcock, Dale F. (Wilmington, DE); Menegus, Robert L. (Wilmington, DE)

    1983-01-01T23:59:59.000Z

    A nuclear reactor includes an active portion with fissionable fuel and neutron moderating material surrounded by neutron reflecting material. A control element in the active portion includes a group of movable rods constructed of neutron-absorbing material. Each rod is movable with respect to the other rods to vary the absorption of neutrons and effect control over neutron flux.

  10. Combined cold compressor/ejector helium refrigerator

    DOE Patents [OSTI]

    Brown, D.P.

    1984-06-05T23:59:59.000Z

    A refrigeration apparatus having an ejector operatively connected with a cold compressor to form a two-stage pumping system. This pumping system is used to lower the pressure, and thereby the temperature of a bath of boiling refrigerant (helium). The apparatus as thus arranged and operated has substantially improved operating efficiency when compared to other processes or arrangements for achieving a similar low pressure.

  11. Closed-loop pulsed helium ionization detector

    DOE Patents [OSTI]

    Ramsey, Roswitha S. (Knoxville, TN); Todd, Richard A. (Knoxville, TN)

    1987-01-01T23:59:59.000Z

    A helium ionization detector for gas chromatography is operated in a constant current, pulse-modulated mode by configuring the detector, electrometer and a high voltage pulser in a closed-loop control system. The detector current is maintained at a fixed level by varying the frequency of fixed-width, high-voltage bias pulses applied to the detector. An output signal proportional to the pulse frequency is produced which is indicative of the charge collected for a detected species.

  12. Combined cold compressor/ejector helium refrigerator

    DOE Patents [OSTI]

    Brown, Donald P. (Southold, NY)

    1985-01-01T23:59:59.000Z

    A refrigeration apparatus having an ejector operatively connected with a cold compressor to form a two-stage pumping system. This pumping system is used to lower the pressure, and thereby the temperature of a bath of boiling refrigerant (helium). The apparatus as thus arranged and operated has substantially improved operating efficiency when compared to other processes or arrangements for achieving a similar low pressure.

  13. The helium fine-structure controversy

    E-Print Network [OSTI]

    Ingvar Lindgren

    2008-10-05T23:59:59.000Z

    There is presently disagreement between theory and experiment as well as between different theoretical calculations concerning the fine-structure splitting of the lowest P state of the neutral helium atom. We believe that we have found a minor error in the formulas used by Drake et al. (Can. J. Phys. 80, 1195 (2002)) in their calculations, and we may have an explanation how the error has occurred. To what extent this might resolve (part of) the discrepancy is not known at present.

  14. Computational and experimental prediction of dust production in pebble bed reactors, Part II

    SciTech Connect (OSTI)

    Mie Hiruta; Gannon Johnson; Maziar Rostamian; Gabriel P. Potirniche; Abderrafi M. Ougouag; Massimo Bertino; Louis Franzel; Akira Tokuhiro

    2013-10-01T23:59:59.000Z

    This paper is the continuation of Part I, which describes the high temperature and high pressure helium environment wear tests of graphite–graphite in frictional contact. In the present work, it has been attempted to simulate a Pebble Bed Reactor core environment as compared to Part I. The experimental apparatus, which is a custom-designed tribometer, is capable of performing wear tests at PBR relevant higher temperatures and pressures under a helium environment. This environment facilitates prediction of wear mass loss of graphite as dust particulates from the pebble bed. The experimental results of high temperature helium environment are used to anticipate the amount of wear mass produced in a pebble bed nuclear reactor.

  15. The Cost of Helium Refrigerators and Coolers for Superconducting Devices as a Function of Cooling at 4 K

    E-Print Network [OSTI]

    Green, Michael A.

    2008-01-01T23:59:59.000Z

    pulse tube coolers as liquefiers of helium and hydrogen. 7.Byrns, R. A. , "Large Helium Refrigerators and Liquefiers,"P. , et al, “Economics of Large Helium Cryogenics Systems:

  16. In situ controlled modification of the helium density in single helium-filled nanobubbles

    SciTech Connect (OSTI)

    David, M.-L., E-mail: marie-laure.david@univ-poitiers.fr; Pailloux, F. [Institut Pprime, UPR 3346 CNRS-Université de Poitiers, SP2MI, 86962 Futuroscope-Chasseneuil cedex (France); Canadian Centre for Electron Microscopy, Mc Master University, 1280 Main Street West, Hamilton, Ontario L8S 4M1 (Canada); Alix, K.; Mauchamp, V.; Pizzagalli, L. [Institut Pprime, UPR 3346 CNRS-Université de Poitiers, SP2MI, 86962 Futuroscope-Chasseneuil cedex (France); Couillard, M.; Botton, G. A. [Canadian Centre for Electron Microscopy, Mc Master University, 1280 Main Street West, Hamilton, Ontario L8S 4M1 (Canada); Department of Materials Science and Engineering, Mc Master University, 1280 Main Street West, Hamilton, Ontario L8S 4M1 (Canada)

    2014-03-28T23:59:59.000Z

    We demonstrate that the helium density and corresponding pressure can be modified in single nano-scale bubbles embedded in semiconductors by using the electron beam of a scanning transmission electron microscope as a multifunctional probe: the measurement probe for imaging and chemical analysis and the irradiation source to modify concomitantly the pressure in a controllable way by fine tuning of the electron beam parameters. The control of the detrapping rate is achieved by varying the experimental conditions. The underlying physical mechanisms are discussed; our experimental observations suggest that the helium detrapping from bubbles could be interpreted in terms of direct ballistic collisions, leading to the ejection of the helium atoms from the bubble.

  17. Design, Analysis and Optimization of the Power Conversion System for the Modular Pebble Bed Reactor System

    E-Print Network [OSTI]

    Pebble Bed Reactor system (MPBR) requires a gas turbine cycle (Brayton cycle) as the power conversion for the gas turbine cycle. The development of an initial reference design for an indirect helium cycle has for the system. Load transients simulations show that the indirect, three-shaft arrangement gas turbine power

  18. MODELING SPACE-TIME DEPENDENT HELIUM BUBBLE EVOLUTION IN TUNGSTEN ARMOR UNDER IFE CONDITIONS

    E-Print Network [OSTI]

    Ghoniem, Nasr M.

    MODELING SPACE-TIME DEPENDENT HELIUM BUBBLE EVOLUTION IN TUNGSTEN ARMOR UNDER IFE CONDITIONS Qiyang dependent Helium transport in finite geometries, including the simultaneous transient production of defects of Helium bubbles. I. INTRODUCTION Helium production and helium bubble evolution in neutron

  19. An Experimental Study of Cold Helium Dispersion in Air

    E-Print Network [OSTI]

    Chorowski, M; Riddone, G

    2002-01-01T23:59:59.000Z

    The Large Hadron Collider (LHC) presently under construction at CERN, will contain about 100 tons of helium mostly located in the underground tunnel and in caverns. Potential failure modes of the accelerator, which may be followed by helium discharge to the tunnel, have been identified and the corresponding helium flows calculated. To verify the analytical calculations of helium dispersion in the tunnel, a dedicated test set-up has been built. It represents a section of the LHC tunnel at a scale 1:13 and is equipped with a controllable helium relief system enabling the simulation of different scenarios of the LHC cryogenic system failures. Corresponding patterns of cold helium dispersion in air have been observed and analysed with respect to oxygen deficiency hazard. We report on the test set-up and the measurement results, which have been scaled to real LHC conditions.

  20. The helium trimer with soft-core potentials

    E-Print Network [OSTI]

    A. Kievsky; E. Garrido; C. Romero-Redondo; P. Barletta

    2011-01-10T23:59:59.000Z

    The helium trimer is studied using two- and three-body soft-core potentials. Realistic helium-helium potentials present an extremely strong short-range repulsion and support a single, very shallow, bound state. The description of systems with more than two helium atoms is difficult due to the very large cancellation between kinetic and potential energy. We analyze the possibility of describing the three helium system in the ultracold regime using a gaussian representation of a widely used realistic potential, the LM2M2 interaction. However, in order to describe correctly the trimer ground state a three-body force has to be added to the gaussian interaction. With this potential model the two bound states of the trimer and the low energy scattering helium-dimer phase shifts obtained with the LM2M2 potential are well reproduced.

  1. Design of the Helium Purifier for IHEP-ADS Helium Purification System

    E-Print Network [OSTI]

    Jianqin, Zhang; Zhuo, Zhang; Rui, Ge

    2015-01-01T23:59:59.000Z

    Helium Purification System is an important sub-system in the Accelerator Driven Subcritical System of the Institute of High Energy Physics(IHEP ADS). The purifier is designed to work at the temperature of 77K. The purifier will work in a flow rate of 5g/s at 20MPa in continuous operation of 12 hours. The oil and moisture are removed by coalescing filters and a dryer, while nitrogen and oxygen are condensed by a phase separator and then adsorbed in several activated carbon adsorption cylinders. After purification, the purified helium has an impurity content of less than 5ppm.

  2. Helium preenrichment in the star-forming regions

    E-Print Network [OSTI]

    Leonid Chuzhoy

    2006-05-15T23:59:59.000Z

    We show that element diffusion can produce large fluctuations in the initial helium abundance of the star-forming clouds. Diffusion time-scale, which in stars is much larger than the Hubble time, can fall below 10^8 years in the neutral gas clouds dominated by collisionless dark matter or with dynamically important radiation or magnetic pressure. Helium diffusion may therefore explain the recent observations of globular clusters, which are inconsistent with initially homogeneous helium distribution.

  3. Mixing, Enhanced Helium and Blue Tails in Globular Clusters

    E-Print Network [OSTI]

    V. Caloi

    2000-12-15T23:59:59.000Z

    We investigate the consequences of an increase in the envelope helium abundance of pre-helium flash red giants in globular clusters. Comparing predictions with the CM diagrams of a few crucial GC, one finds no evidence for a substantial increase in the surface helium content of HB members of these clusters, at least for objects in the RR Lyrae region or close to it. The possibility that the most peculiar giants belong to the asymptotic giant branch is discussed. The consequences of a delay in the helium flash are briefly examined.

  4. Helium isotopes in geothermal systems- Iceland, The Geysers,...

    Open Energy Info (EERE)

    Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Helium isotopes in geothermal systems- Iceland, The Geysers, Raft River and Steamboat Springs...

  5. ON QUANTIFICATION OF HELIUM EMBRITTLEMENT IN FERRITIC/MARTENSITIC STEELS

    SciTech Connect (OSTI)

    Gelles, David S.

    2000-12-01T23:59:59.000Z

    Helium accumulation due to transmutation has long been considered a potential cause for embrittlement in ferritic/martensitic steels. Three Charpy impact databases involving nickel- and boron-doped alloys are quantified with respect to helium accumulation, and it is shown that all predict a very large effect of helium production on embrittlement. If these predictions are valid, use of Ferritic/Martensitic steels for Fusion first wall applications is highly unlikely. It is therefore necessary to reorient efforts regarding development of these steels for fusion applications to concentrate on the issue of helium embrittlement.

  6. Carbon Dioxide and Helium Emissions from a Reservoir of Magmatic...

    Open Energy Info (EERE)

    Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Carbon Dioxide and Helium Emissions from a Reservoir of Magmatic Gas Beneath Mammoth...

  7. Mantle Helium And Carbon Isotopes In Separation Creek Geothermal...

    Open Energy Info (EERE)

    Mantle Helium And Carbon Isotopes In Separation Creek Geothermal Springs, Three Sisters Area, Central Oregon- Evidence For Renewed Volcanic Activity Or A Long Term Steady State...

  8. Structure of processes in flow reactor and closed reactor: Flow reactor

    E-Print Network [OSTI]

    Greifswald, Ernst-Moritz-Arndt-Universität

    Structure of processes in flow reactor and closed reactor: Flow reactor Closed reactor Active Zone -- chemical quasi- equilibria, similarity principles and macroscopic kinetics", in: Lectures on Plasma Physics

  9. Triple Differential Cross sections and Nuclear Recoil in Two-Photon Double Ionization of Helium

    E-Print Network [OSTI]

    Horner, Daniel A.

    2008-01-01T23:59:59.000Z

    Two-Photon Double Ionization of Helium D. A. Horner, 1 C. W.photon double ionization of helium are calculated using theDouble ionization of the helium atom by two XUV photons in

  10. The Helium Cooling System and Cold Mass Support System for the MICE Coupling Solenoid

    E-Print Network [OSTI]

    2008-01-01T23:59:59.000Z

    18, No. 2, LBNL-63592 The Helium Cooling System and Coldmass support system and helium cooling system are discussedc and ? = 420 mm III. THE HELIUM COOLING SYSTEM The coupling

  11. Isotopes of helium, hydrogen, and carbon as groundwater tracers in aquifers along the Colorado River

    E-Print Network [OSTI]

    Haber, Samuel Ainsworth

    2009-01-01T23:59:59.000Z

    composition of radiogenic helium and its use to studyH. , Lupton, J.E. (1981) Helium-3 and mantle volatiles inand Izbicki, J.A. (2003). Helium isotope studies in the

  12. Cross sections for short pulse single and double ionization of helium

    E-Print Network [OSTI]

    Palacios, Alicia; Rescigno, Thomas N.; McCurdy, C. William

    2008-01-01T23:59:59.000Z

    ton double ionization of helium at 20 eV above threshold. 1single and double ionization of helium A. Palacios, 1 T. N.double ionization of helium. In particular it is shown how

  13. The Helium Cooling System and Cold Mass Support System for the MICE Coupling Solenoid

    E-Print Network [OSTI]

    2008-01-01T23:59:59.000Z

    LBNL-63592 The Helium Cooling System and Cold Mass Supportsystem and helium cooling system are discussed in detail.420 mm III. THE HELIUM COOLING SYSTEM The coupling magnet is

  14. Alternatives for Helium-3 in Multiplicity Counters

    SciTech Connect (OSTI)

    Ely, James H.; Siciliano, Edward R.; Lintereur, Azaree T.; Swinhoe, Martyn T.

    2013-04-01T23:59:59.000Z

    Alternatives to helium-3 are being actively pursued due to the shortage and rising costs of helium-3. For safeguards applications, there are a number of ongoing investigations to find alternatives that provide the same capability in a cost-effective manner. One of the greatest challenges is to find a comparable alternative for multiplicity counters, since they require high efficiency and short collection or die-away times. Work has been progressing on investigating three commercially available alternatives for high efficiency multiplicity counters: boron trifluoride (BF3) filled proportional tubes, boron-lined proportional tubes, and lithium fluoride with zinc sulfide coated light guides. The baseline multiplicity counter used for the investigation is the Epithermal Neutron Multiplicity Counter with 121 helium-3 filled tubes at 10 atmosphere pressure, which is a significant capability to match. The primary tool for the investigation has been modeling and simulation using the Monte Carlo N-Particle eXtended (MCNPX) radiation transport program, with experiments to validate the models. To directly calculate the coincidence rates in boron-lined (and possibly other) detectors, the MCNPX code has been enhanced to allow the existing coincidence tally to be used with energy deposition rather than neutron capture reactions. This allows boron-lined detectors to be modeled more accurately. Variations of tube number and diameter along with variations in the amount of inter-tube moderator have been conducted for the BF3 and boron-lined cases. Tube pressure was investigated for BF3, up to two atmospheres, as well as optimal boron thickness in the boron-lined tubes. The lithium fluoride was modeled as sheets of material with light guides in between, and the number and thickness of the sheets investigated. The amount of light guide, which in this case doubles as a moderator, was also optimized. The results of these modeling and simulation optimization investigations are described and results presented.

  15. Polarized Helium to Image the Lung

    E-Print Network [OSTI]

    Leduc, M; Leduc, Mich\\`{e}le; Nacher, Pierre-Jean

    2006-01-01T23:59:59.000Z

    The main findings of the european PHIL project (Polarised Helium to Image the Lung) are reported. State of the art optical pumping techniques for polarising ^3He gas are described. MRI methodological improvements allow dynamical ventilation images with a good resolution, ultimately limited by gas diffusion. Diffusion imaging appears as a robust method of lung diagnosis. A discussion of the potential advantage of low field MRI is presented. Selected PHIL results for emphysema are given, with the perspectives that this joint work opens up for the future of respiratory medicine.

  16. Production of thorium-229 using helium nuclei

    DOE Patents [OSTI]

    Mirzadeh, Saed (Knoxville, TN) [Knoxville, TN; Garland, Marc Alan (Knoxville, TN) [Knoxville, TN

    2010-12-14T23:59:59.000Z

    A method for producing .sup.229Th includes the steps of providing .sup.226Ra as a target material, and bombarding the target material with alpha particles, helium-3, or neutrons to form .sup.229Th. When neutrons are used, the neutrons preferably include an epithermal neutron flux of at least 1.times.10.sup.13 n s.sup.-1cm.sup.-2. .sup.228Ra can also be bombarded with thermal and/or energetic neutrons to result in a neutron capture reaction to form .sup.229Th. Using .sup.230Th as a target material, .sup.229Th can be formed using neutron, gamma ray, proton or deuteron bombardment.

  17. Classical Transitions in Superfluid Helium 3

    E-Print Network [OSTI]

    I-Sheng Yang; S. -H. Henry Tye; Benjamin Shlaer

    2011-10-10T23:59:59.000Z

    We argue that classical transitions can be the key to explaining the long standing puzzle of the fast A-B phase transition observed in superfluid Helium 3 while standard theory expects it to be unobservably slow. Collisions between domain walls are shown to be capable of reaching phases inaccessible through homogenous nucleation on the measured timescales. We demonstrate qualitative agreements with prior observations and provide a definite, distinctive prediction that could be verified through future experiments or, perhaps, a specific analysis of existing data.

  18. Lamb shift in muonic helium ion

    E-Print Network [OSTI]

    A. P. Martynenko

    2014-07-09T23:59:59.000Z

    The Lamb shift (2P_{1/2}-2S_{1/2}) in the muonic helium ion (mu ^4_2He)^+ is calculated with the account of contributions of orders alpha^3, alpha^4, alpha^5 and alpha^6. Special attention is given to corrections of the electron vacuum polarization, the nuclear structure and recoil effects. The obtained numerical value of the Lamb shift 1379.028 meV can be considered as a reliable estimate for the comparison with experimental data.

  19. Kosterlitz-Thouless Transition in Helium Films

    E-Print Network [OSTI]

    Agnolet, Glenn; MCQUEENEY, DF; REPPY, JD.

    1989-01-01T23:59:59.000Z

    and the Materials Science Center, Cornell University, Ithaca, Xetv York 14853 (Received 4 November 1988) The superAuid response of helium Alms with transition temperatures ranging from 70 mK to 0.5 K has been studied using a torsional oscillator technique. A...-Thouless theory. Comparisons with the dynamic theory reveal nonuniversal behavior as a function of coverage. INTRODUCTION The superAuid phase transition in thin He films on planar surfaces is generally acknowledged to be a realiza- tion of a Kosterlitz...

  20. Beryllium Use in the Advanced Test Reactor

    SciTech Connect (OSTI)

    Glen R. Longhurst

    2007-12-01T23:59:59.000Z

    The Advanced Test Reactor (ATR) at the Idaho National Laboratory (INL) began operation in 1967. It makes use of a unique serpentine fuel core design and a beryllium reflector. Reactor control is achieved with rotating beryllium cylinders to which have been fastened plates of hafnium. Over time, the beryllium develops rather high helium content because of nuclear transmutations and begins to swell. The beryllium must be replaced at nominally 10-year intervals. Determination of when the replacement is made is by visual observation using a periscope to examine the beryllium surface for cracking and swelling. Disposition of the irradiated beryllium was once accomplished in the INL’s Radioactive Waste Management Complex, but that is no longer possible. Among contributing reasons are high levels of specific radioactive contaminants including transuranics. The INL is presently considering disposition pathways for this irradiated beryllium, but presently is storing it in the canal adjacent to the reactor. Numerous issues are associated with this situation including (1) Is there a need for ultra-low uranium material? (2) Is there a need to recover tritium from irradiated beryllium either because this is a strategic material resource or in preparation for disposal? (3) Is there a need to remove activation and fission products from irradiated beryllium? (4) Will there be enough material available to meet requirements for research reactors (fission and fusion)? In this paper will be discussed the present status of considerations on these issues.

  1. Hybrid adsorptive membrane reactor

    DOE Patents [OSTI]

    Tsotsis, Theodore T. (Huntington Beach, CA); Sahimi, Muhammad (Altadena, CA); Fayyaz-Najafi, Babak (Richmond, CA); Harale, Aadesh (Los Angeles, CA); Park, Byoung-Gi (Yeosu, KR); Liu, Paul K. T. (Lafayette Hill, PA)

    2011-03-01T23:59:59.000Z

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  2. Optimum Reactor Outlet Temperatures for High Temperature Gas-Cooled Reactors Integrated with Industrial Processes

    SciTech Connect (OSTI)

    Lee O. Nelson

    2011-04-01T23:59:59.000Z

    This report summarizes the results of a temperature sensitivity study conducted to identify the optimum reactor operating temperatures for producing the heat and hydrogen required for industrial processes associated with the proposed new high temperature gas-cooled reactor. This study assumed that primary steam outputs of the reactor were delivered at 17 MPa and 540°C and the helium coolant was delivered at 7 MPa at 625–925°C. The secondary outputs of were electricity and hydrogen. For the power generation analysis, it was assumed that the power cycle efficiency was 66% of the maximum theoretical efficiency of the Carnot thermodynamic cycle. Hydrogen was generated via the hightemperature steam electrolysis or the steam methane reforming process. The study indicates that optimum or a range of reactor outlet temperatures could be identified to further refine the process evaluations that were developed for high temperature gas-cooled reactor-integrated production of synthetic transportation fuels, ammonia, and ammonia derivatives, oil from unconventional sources, and substitute natural gas from coal.

  3. Nuclear reactor engineering

    SciTech Connect (OSTI)

    Glasstone, S.; Sesonske, A.

    1982-07-01T23:59:59.000Z

    A book is reviewed which emphasizes topics directly related to the light water reactor power plant and the fast reactor power system. Current real-world problems are addressed throughout the text, and a chapter on safety includes much of the postThree Mile Island impact on operating systems. Topics covered include Doppler broadening, neutron resonances, multigroup diffusion theory, reactor kinetics, reactor control, energy removal, nonfuel materials, reactor fuel, radiation protection, environmental effects, and reactor safety.

  4. Study of Impurity-Helium Condensates Formed by Multishell Nanoclusters

    E-Print Network [OSTI]

    Mao, Shun

    2014-12-17T23:59:59.000Z

    Impurity-helium condensates (IHCs) are porous gel-like materials created by injecting a mixed beam of helium gas and an impurity gas into super fluid 4He. Van der Waals forces lead to the formation of clusters of impurities each surrounded by a thin...

  5. DIRECT EVALUATION OF THE HELIUM ABUNDANCES IN OMEGA CENTAURI

    SciTech Connect (OSTI)

    Dupree, A. K.; Avrett, E. H., E-mail: dupree@cfa.harvard.edu, E-mail: eavrett@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)

    2013-08-20T23:59:59.000Z

    A direct measure of the helium abundances from the near-infrared transition of He I at 1.08 {mu}m is obtained for two nearly identical red giant stars in the globular cluster Omega Centauri. One star exhibits the He I line; the line is weak or absent in the other star. Detailed non-local thermal equilibrium semi-empirical models including expansion in spherical geometry are developed to match the chromospheric H{alpha}, H{beta}, and Ca II K lines, in order to predict the helium profile and derive a helium abundance. The red giant spectra suggest a helium abundance of Y {<=} 0.22 (LEID 54064) and Y = 0.39-0.44 (LEID 54084) corresponding to a difference in the abundance {Delta}Y {>=} 0.17. Helium is enhanced in the giant star (LEID 54084) that also contains enhanced aluminum and magnesium. This direct evaluation of the helium abundances gives observational support to the theoretical conjecture that multiple populations harbor enhanced helium in addition to light elements that are products of high-temperature hydrogen burning. We demonstrate that the 1.08 {mu}m He I line can yield a helium abundance in cool stars when constraints on the semi-empirical chromospheric model are provided by other spectroscopic features.

  6. Helium nanobubble release from Pd surface: An atomic simulation

    SciTech Connect (OSTI)

    Wang, Liang; Hu, Wangyu; Deng, Huiqiu; Xiao, Shifang; Yang, Jianyu; Gao, Fei; Heinisch, Howard L.; Hu, Shilin

    2011-02-14T23:59:59.000Z

    Molecular dynamic simulations of helium atoms escaping from a helium-filled nano-bubble near the surface of crystalline palladium reveal unexpected behavior. Significant deformation and cracking near the helium bubble occur initially, and then a channel forms between the bubble and the surface, providing a pathway for helium atoms to propagate towards the surface. The helium atoms erupt from the bubble in an instantaneous and volcano-like process, which leads to surface deformation consisting of cavity formation on the surface, along with modification and atomic rearrangement at the periphery of the cavity. The present simulation results show that, near the palladium surface, there is a helium-bubble-free zone, or denuded zone, with a typical thickness of about 3.0 nm. Combined with experimental measurements and continuum-scale evolutionary model predictions, the present atomic simulations demonstrate that the thickness of the denuded zone, which contains a low concentration of helium atoms, is somewhat larger than the diameter of the helium bubbles in the metal tritide. Furthermore, a relationship between the tensile strength and thickness of metal film is also determined.

  7. Diss. ETH Nr. 10714 Helium und Tritium als Tracer fr

    E-Print Network [OSTI]

    Aeschbach-Hertig, Werner

    Diss. ETH Nr. 10714 Helium und Tritium als Tracer für physikalische Prozesse in Seen ABHANDLUNG zur Zürich 1994 #12;Kurzfassung ix Kurzfassung Der radioaktive Zerfall von 3H (Tritium) zu 3He mit einer Fluide aus dem Erdinnern. Helium und Tritium werden massenspektrometrisch analysiert. Im Rahmen dieser Ar

  8. Heterogeneous cavitation in liquid helium 4 near a glass plate

    E-Print Network [OSTI]

    Caupin, Frédéric

    Heterogeneous cavitation in liquid helium 4 near a glass plate X. Chavanne, S. Balibar and F wave to study cavitation, i.e. the nucleation of bubbles, in liquid helium 4 near a clean glass plate and threshold pressures in the range 0 to -3 bar, significantly less negative than for homogeneous cavitation

  9. Medium-size high-temperature gas-cooled reactor

    SciTech Connect (OSTI)

    Peinado, C.O.; Koutz, S.L.

    1980-08-01T23:59:59.000Z

    This report summarizes high-temperature gas-cooled reactor (HTGR) experience for the 40-MW(e) Peach Bottom Nuclear Generating Station of Philadelphia Electric Company and the 330-MW(e) Fort St. Vrain Nuclear Generating Station of the Public Service Company of Colorado. Both reactors are graphite moderated and helium cooled, operating at approx. 760/sup 0/C (1400/sup 0/F) and using the uranium/thorium fuel cycle. The plants have demonstrated the inherent safety characteristics, the low activation of components, and the high efficiency associated with the HTGR concept. This experience has been translated into the conceptual design of a medium-sized 1170-MW(t) HTGR for generation of 450 MW of electric power. The concept incorporates inherent HTGR safety characteristics (a multiply redundant prestressed concrete reactor vessel (PCRV), a graphite core, and an inert single-phase coolant) and engineered safety features (core auxiliary cooling, relief valve, and steam generator dump systems).

  10. A superfluid helium converter for accumulation and extraction of ultracold neutrons

    E-Print Network [OSTI]

    O. Zimmer; K. Baumann; M. Fertl; B. Franke; S. Mironov; C. Plonka; D. Rich; P. Schmidt-Wellenburg; H. -F. Wirth; B. van den Brandt

    2007-05-27T23:59:59.000Z

    We report the first successful extraction of accumulated ultracold neutrons (UCN) from a converter of superfluid helium, in which they were produced by downscattering neutrons of a cold beam from the Munich research reactor. Windowless UCN extraction is performed in vertical direction through a mechanical cold valve. This prototype of a versatile UCN source is comprised of a novel cryostat designed to keep the source portable and to allow for rapid cooldown. We measured time constants for UCN storage and extraction into a detector at room temperature, with the converter held at various temperatures between 0.7 and 1.3 K. The UCN production rate inferred from the count rate of extracted UCN is close to the theoretical expectation.

  11. SRS Small Modular Reactors

    SciTech Connect (OSTI)

    None

    2012-04-27T23:59:59.000Z

    The small modular reactor program at the Savannah River Site and the Savannah River National Laboratory.

  12. SRS Small Modular Reactors

    ScienceCinema (OSTI)

    None

    2014-05-21T23:59:59.000Z

    The small modular reactor program at the Savannah River Site and the Savannah River National Laboratory.

  13. Reactor safety method

    DOE Patents [OSTI]

    Vachon, Lawrence J. (Clairton, PA)

    1980-03-11T23:59:59.000Z

    This invention relates to safety means for preventing a gas cooled nuclear reactor from attaining criticality prior to start up in the event the reactor core is immersed in hydrogenous liquid. This is accomplished by coating the inside surface of the reactor coolant channels with a neutral absorbing material that will vaporize at the reactor's operating temperature.

  14. HELIUM EFFECTS ON DISPLACEMENT CASCADE IN TUNGSTEN

    SciTech Connect (OSTI)

    Setyawan, Wahyu; Nandipati, Giridhar; Roche, Kenneth J.; Heinisch, Howard L.; Kurtz, Richard J.; Wirth, Brian D.

    2013-09-30T23:59:59.000Z

    Molecular dynamics (MD) simulations were performed to investigate He effects on displacement cascades in W. Helium content, proportion of interstitial and substitutional He and temperature were varied to reveal the various effects. The effect of interstitial He on the number of self-interstitial atoms (SIAs) produced during cascade damage appears to be insignificant. However, interstitial He tends to fill a vacancy (V). Nevertheless, this process is less favorable than SIA-V recombination particularly when excess SIAs are present before a cascade. The efficiency of He filling and SIA-V recombination increases as temperature increases due to increased point defect mobility. Likewise, substitutional He is more susceptible to displacement during a collision cascade than W. This susceptibility increases towards higher temperatures. Consequently, the number of surviving V is governed by the interplay between displaced substitutional He and SIA-V recombination. The temperature dependence of these processes results in a minimum number of V reached at an intermediate temperature.

  15. Compact hydrogen/helium isotope mass spectrometer

    DOE Patents [OSTI]

    Funsten, Herbert O. (Los Alamos, NM); McComas, David J. (Los Alamos, NM); Scime, Earl E. (Morgantown, WV)

    1996-01-01T23:59:59.000Z

    The compact hydrogen and helium isotope mass spectrometer of the present invention combines low mass-resolution ion mass spectrometry and beam-foil interaction technology to unambiguously detect and quantify deuterium (D), tritium (T), hydrogen molecule (H.sub.2, HD, D.sub.2, HT, DT, and T.sub.2), .sup.3 He, and .sup.4 He concentrations and concentration variations. The spectrometer provides real-time, high sensitivity, and high accuracy measurements. Currently, no fieldable D or molecular speciation detectors exist. Furthermore, the present spectrometer has a significant advantage over traditional T detectors: no confusion of the measurements by other beta-emitters, and complete separation of atomic and molecular species of equivalent atomic mass (e.g., HD and .sup.3 He).

  16. Searching for dark matter with helium atom

    E-Print Network [OSTI]

    Imre Ferenc Barna

    2006-08-10T23:59:59.000Z

    With the help of the boost operator we can model the interaction between a weakly interacting particle(WIMP) of dark matter(DAMA) and an atomic nuclei. Via this "kick" we calculate the total electronic excitation cross section of the helium atom. The bound spectrum of He is calculated through a diagonalization process with a configuration interaction (CI) wavefunction built up from Slater orbitals. All together 19 singly- and doubly-excited atomic sates were taken with total angular momenta of L=0,1 and 2. Our calculation may give a rude estimation about the magnitude of the total excitation cross section which could be measured in later scintillator experiments. The upper limit of the excitation cross section is $9.7\\cdot 10^{-8}$ barn.

  17. Helium solubility in SON68 nuclear waste glass

    SciTech Connect (OSTI)

    Fares, Toby; Peuget, Sylvain; Bouty, Olivier; Broudic, Veronique; Maugeri, Emilio; Bes, Rene; Jegou, Christophe [CEA, DEN, DTCD SECM LMPA, F-30207 Marcoule, Bagnols Sur Cez, (France); Chamssedine, Fadel; Sauvage, Thierry [CNRS, CEMHTI, F-245071 Orleans, (France); Deschanels, Xavier [LNAR, Marcoule Inst Separat Chem, F-30207 Bagnols Sur Ceze, (France)

    2012-12-15T23:59:59.000Z

    Helium behavior in a sodium borosilicate glass (SON68) dedicated to the immobilization of high-level nuclear waste is examined. Two experimental approaches on nonradioactive glass specimens are implemented: pressurized helium infusion experiments and {sup 3}He ion implantation experiments. The temperature variation of helium solubility in SON68 glass was determined and analyzed with the harmonic oscillator model to determine values of the energy of interaction E(0) at the host sites (about -4000 J/mol), the vibration frequency (about 1.7 x 10{sup 11} s{sup -1}), and the density of solubility sites (2.2 x 10{sup 21} sites cm{sup -3}). The implantation experiments show that a non diffusive transport phenomenon (i.e., athermal diffusion) is involved in the material when the helium concentration exceeds 2.3 x 10{sup 21} He cm{sup -3}, and thus probably as soon as it exceeds the density of solubility sites accessible to helium in the glass. We propose that this transport mechanism could be associated with the relaxation of the stress gradient induced by the implanted helium profile, which is favored by the glass damage. Microstructural characterization by TEM and ESEM of glass specimens implanted with high helium concentrations showed a homogeneous microstructure free of bubbles, pores, or cracking at a scale of 10 nm. (authors)

  18. Primordial Helium And the Cosmic Background Radiation

    E-Print Network [OSTI]

    Gary Steigman

    2010-04-29T23:59:59.000Z

    The products of primordial nucleosynthesis and the cosmic microwave background (CMB) photons are relics from the early evolution of the Universe whose observations probe the standard model of cosmology and provide windows on new physics beyond the standard models of cosmology and of particle physics. In the standard, hot big bang cosmology, long before any stars have formed a significant fraction (~25%) of the baryonic mass in the Universe should be in the form of helium-4 nuclei. Since current 4He observations are restricted to low redshift regions where stellar nucleosynthesis has occurred, observations of high redshift, prestellar 4He would constitute a fundamental test of the hot, big bang cosmology. At recombination, long after big bang nucleosynthesis (BBN) has ended, the temperature anisotropy spectrum imprinted on the CMB depends on the 4He abundance through its connection to the electron density and the effect of the electron density on Silk damping. Since the relic abundance of 4He is relatively insensitive to the universal density of baryons, but is sensitive to a non-standard, early Universe expansion rate, the primordial mass fraction of 4He, Yp, offers a test of the consistency of the standard models of BBN and the CMB and, provides constraints on non-standard physics. Here, the WMAP seven year data (supplemented by other CMB experiments), which lead to an indirect determination of Yp at high redshift, are compared to the BBN predictions and to the independent, direct observations of 4He in low redshift, extragalactic HII regions. At present, given the very large uncertainties in the CMB-determined primordial 4He abundance (as well as for the helium abundances inferred from H II region observations), any differences between the BBN predictions and the CMB observations are small, at a level < 1.5 sigma.

  19. Flexible corrugated cryotransferlines, long term experience at JET and the experience with supercritical helium flow conditions

    E-Print Network [OSTI]

    Obert, W

    1996-01-01T23:59:59.000Z

    Flexible corrugated cryotransferlines, long term experience at JET and the experience with supercritical helium flow conditions

  20. Physics 216 Spring 2012 The Variational Computation of the Ground State Energy of Helium

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    Physics 216 Spring 2012 The Variational Computation of the Ground State Energy of Helium I. Introduction to the variational computation The Hamiltonian for the two-electron system of the helium atom is state energy of the helium atom. The ground state wave function of the helium atom is of the form: 1 2

  1. Physics 139B Fall 2009 The Variational Computation of the Ground State Energy of Helium

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    Physics 139B Fall 2009 The Variational Computation of the Ground State Energy of Helium I. Introduction to the variational computation The Hamiltonian for the two-electron system of the helium atom is state energy of the helium atom. The ground state wave function of the helium atom is of the form: 1 2

  2. Flexible Corrugated Cryotransferlines, Long Term Experience at JET and the Experience with Supercritical Helium Flow Conditions

    E-Print Network [OSTI]

    Flexible Corrugated Cryotransferlines, Long Term Experience at JET and the Experience with Supercritical Helium Flow Conditions

  3. Recombination of He+ in a pulsed helium plasma

    E-Print Network [OSTI]

    Chang, Cheng-shu

    1967-01-01T23:59:59.000Z

    -body Recombinatior Rate Coefficient A for Helium Plasma at Pressure 5 and 6 mm Hg Calculs. ted Values of Electron Temperature Te and. 'Density Ne and the T1"ree-body Recombination Rate Coefficient A for Helium Plasma at Pressure 7 and 8 mm Hg 38 1 ?-. 1 i o.... . ! o. ' T. inc foe Hc '. ior. . 7 i, "1 2 0 i m'" Hg 7. j':lectron Vcm'ocr. . tur= T and Electron Dc!is i. ty a 'h, '" c L:i on o'* Time for Helium Plasma I! . J. r 4! i:lm ii)& ~ ~ ~ ~ ~ ~ 8. Electron Tempo. ature Te and Electron Density N as a...

  4. Nuclear reactor

    DOE Patents [OSTI]

    Thomson, Wallace B. (Severna Park, MD)

    2004-03-16T23:59:59.000Z

    A nuclear reactor comprising a cylindrical pressure vessel, an elongated annular core centrally disposed within and spaced from the pressure vessel, and a plurality of ducts disposed longitudinally of the pressure vessel about the periphery thereof, said core comprising an annular active portion, an annular reflector just inside the active portion, and an annular reflector just outside the active a portion, said annular active portion comprising rectangular slab, porous fuel elements radially disposed around the inner reflector and extending the length of the active portion, wedge-shaped, porous moderator elements disposed adjacent one face of each fuel element and extending the length of the fuel element, the fuel and moderator elements being oriented so that the fuel elements face each other and the moderator elements do likewise, adjacent moderator elements being spaced to provide air inlet channels, and adjacent fuel elements being spaced to provide air outlet channels which communicate with the interior of the peripheral ducts, and means for introducing air into the air inlet channels which passes through the porous moderator elements and porous fuel elements to the outlet channel.

  5. An effective loading method of americium targets in fast reactors

    SciTech Connect (OSTI)

    Ohki, Shigeo; Sato, Isamu; Mizuno, Tomoyasu; Hayashi, Hideyuki; Tanaka, Kenya [Japan Atomic Energy Agency, 4002, Narita-cho, O-arai-machi, Higashi-Ibaraki-gun, Ibaraki 311-1393 (Japan)

    2007-07-01T23:59:59.000Z

    Recently, the development of target fuel with high americium (Am) content has been launched for the reduction of the overall fuel fabrication cost of the minor actinide (MA) recycling. In the framework of the development, this study proposes an effective loading method of Am targets in fast reactors. As a result of parametric survey calculations, we have found the ring-shaped target loading pattern between inner and outer core regions. This loading method is satisfactory both in core characteristics and in MA transmutation property. It should be noted that the Am targets can contribute to the suppression of the core power distribution change due to burnup. The major drawback of Am target is the production of helium gas. A target design modification by increasing the cladding thickness is found to be the most feasible measure to cope with the helium production. (authors)

  6. Atmospheric Pressure Reactor System | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Atmospheric Pressure Reactor System Atmospheric Pressure Reactor System The atmospheric pressure reactor system is designed for testing the efficiency of various catalysts for the...

  7. NEWS & VIEWS synchrotron or helium-lamp studies. But

    E-Print Network [OSTI]

    Loss, Daniel

    NEWS & VIEWS synchrotron or helium-lamp studies. But the low energy of the laser photons raises that of a conventional metal. The effects of projection have led to detailed quantitative insights into the properties

  8. Ab initio study of helium behavior in titanium tritides

    SciTech Connect (OSTI)

    Liang, J. H.; Dai, Yunya; Yang, Li; Peng, SM; Fan, K. M.; Long, XG; Zhou, X. S.; Zu, Xiaotao; Gao, Fei

    2013-03-01T23:59:59.000Z

    Ab initio calculations based on density functional theory have been performed to investigate the relative stability of titanium tritides and the helium behavior in stable titanium tritides. The results show that the ?-phase TiT1.5 without two tritium along the [100] direction (TiT1.5[100]) is more stable than other possible structures. The stability of titanium tritides decrease with the increased generation of helium in TiT1.5[100]. In addition, helium generated by tritium decay prefers locating at a tetrahedral site, and favorably migrates between two neighbor vacant tetrahedral sites through an intermediate octahedral site in titanium tritides, with a migration energy of 0.23 eV. Furthermore, helium is easily accumulated on a (100) plane in ?-phase TiT1.5[100].

  9. Helium Isotopes in Geothermal and Volcanic Gases of the Western...

    Open Energy Info (EERE)

    Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Helium Isotopes in Geothermal and Volcanic Gases of the Western United States, II. Long...

  10. Scanning-helium-ion-beam lithography with hydrogen silsesquioxane resist

    E-Print Network [OSTI]

    Winston, Donald

    A scanning-helium-ion-beam microscope is now commercially available. This microscope can be used to perform lithography similar to, but of potentially higher resolution than, scanning electron-beam lithography. This article ...

  11. The Hall D solenoid helium refrigeration system at JLab

    SciTech Connect (OSTI)

    Laverdure, Nathaniel A. [JLAB; Creel, Jonathan D. [JLAB; Dixon, Kelly d. [JLAB; Ganni, Venkatarao [JLAB; Martin, Floyd D. [JLAB; Norton, Robert O. [JLAB; Radovic, Sasa [JLAB

    2014-01-01T23:59:59.000Z

    Hall D, the new Jefferson Lab experimental facility built for the 12GeV upgrade, features a LASS 1.85 m bore solenoid magnet supported by a 4.5 K helium refrigerator system. This system consists of a CTI 2800 4.5 K refrigerator cold box, three 150 hp screw compressors, helium gas management and storage, and liquid helium and nitrogen storage for stand-alone operation. The magnet interfaces with the cryo refrigeration system through an LN2-shielded distribution box and transfer line system, both designed and fabricated by JLab. The distribution box uses a thermo siphon design to respectively cool four magnet coils and shields with liquid helium and nitrogen. We describe the salient design features of the cryo system and discuss our recent commissioning experience.

  12. Helium Isotopes In Geothermal And Volcanic Gases Of The Western...

    Open Energy Info (EERE)

    Helium Isotopes In Geothermal And Volcanic Gases Of The Western United States, I, Regional Variability And Magmatic Origin Jump to: navigation, search OpenEI Reference LibraryAdd...

  13. The effects of He I 10830 on helium abundance determinations

    E-Print Network [OSTI]

    Aver, Erik; Skillman, Evan D

    2015-01-01T23:59:59.000Z

    Observations of helium and hydrogen emission lines from metal-poor extragalactic H II regions provide an independent method for determining the primordial helium abundance, Y_p. Traditionally, the emission lines employed are in the visible wavelength range, and the number of suitable lines is limited. Furthermore, when using these lines, large systematic uncertainties in helium abundance determinations arise due to the degeneracy of physical parameters, such as temperature and density. Recently, Izotov, Thuan, & Guseva (2014) have pioneered adding the He 10830 infrared emission line in helium abundance determinations. The strong electron density dependence of He 10830 makes it ideal for better constraining density, potentially breaking the degeneracy with temperature. We revisit our analysis of the dataset published by Izotov, Thuan, & Stasinska (2007) and incorporate the newly available observations of He 10830 by scaling them using the observed-to-theoretical Paschen-gamma ratio. The solutions are b...

  14. Regional And Local Trends In Helium Isotopes, Basin And Range...

    Open Energy Info (EERE)

    And Local Trends In Helium Isotopes, Basin And Range Province, Western North America- Evidence For Deep Permeable Pathways Jump to: navigation, search OpenEI Reference LibraryAdd...

  15. THE POPULATION OF HELIUM-MERGER PROGENITORS: OBSERVATIONAL PREDICTIONS

    SciTech Connect (OSTI)

    Fryer, Chris L. [CCS Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)] [CCS Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Belczynski, Krzysztof; Bulik, Tomasz [Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warsaw (Poland)] [Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warsaw (Poland); Berger, Edo [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)] [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Thoene, Christina [IAA-CSIC, Glorieta de la Astronomia s/n, E-18008 Granada (Spain)] [IAA-CSIC, Glorieta de la Astronomia s/n, E-18008 Granada (Spain); Ellinger, Carola [Department of Physics, University of Texas at Arlington, 502 Yates Street, Box 19059, Arlington, TX 76019 (United States)] [Department of Physics, University of Texas at Arlington, 502 Yates Street, Box 19059, Arlington, TX 76019 (United States)

    2013-02-20T23:59:59.000Z

    The helium-merger gamma-ray burst (GRB) progenitor is produced by the rapid accretion onto a compact remnant (neutron star or black hole) when it undergoes a common envelope inspiral with its companion's helium core. This merger phase produces a very distinct environment around these outbursts and recent observations suggest that, in some cases, we are detecting the signatures of the past merger in the GRB afterglow. These observations allow us, for the first time, to study the specific features of the helium-merger progenitor. In this paper, we couple population synthesis calculations to our current understanding of GRB engines and common envelope evolution to make observational predictions for the helium-merger GRB population. Many mergers do not produce GRB outbursts and we discuss the implications of these mergers with the broader population of astrophysical transients.

  16. Underground helium travels to the Earth's surface via aquifers...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of South America; it supplies water to more than 15 million people. Scientists found helium pools in this aquifer and is released to the atmosphere when the water reaches the...

  17. Etching of Graphene Devices with a Helium Ion Beam

    E-Print Network [OSTI]

    Baugher, Britton William Herb

    We report on the etching of graphene devices with a helium ion beam, including in situ electrical measurement during lithography. The etching process can be used to nanostructure and electrically isolate different regions ...

  18. Technique to eliminate helium induced weld cracking in stainless steels

    SciTech Connect (OSTI)

    Chin-An Wang; Chin, B.A. [Auburn Univ., AL (United States). Dept. of Materials Engineering; Grossbeck, M.L. [Oak Ridge National Lab., TN (United States)

    1992-12-31T23:59:59.000Z

    Experiments have shown that Type 316 stainless steel is susceptible to heat-affected-zone (HAZ) cracking upon cooling when welded using the gas tungsten arc (GTA) process under lateral constraint. The cracking has been hypothesized to be caused by stress-assisted helium bubble growth and rupture at grain boundaries. This study utilized an experimental welding setup which enabled different compressive stresses to be applied to the plates during welding. Autogenous GTA welds were produced in Type 316 stainless steel doped with 256 appm helium. The application of a compressive stress, 55 Mpa, during welding suppressed the previously observed catastrophic cracking. Detailed examinations conducted after welding showed a dramatic change in helium bubble morphology. Grain boundary bubble growth along directions parallel to the weld was suppressed. Results suggest that stress-modified welding techniques may be used to suppress or eliminate helium-induced cracking during joining of irradiated materials.

  19. A vectorized heat transfer model for solid reactor cores

    SciTech Connect (OSTI)

    Rider, W.J.; Cappiello, M.W.; Liles, D.R.

    1990-01-01T23:59:59.000Z

    The new generation of nuclear reactors includes designs that are significantly different from light water reactors. Among these new reactor designs is the Modular High-Temperature Gas-Cooled Reactor (MHTGR). In addition, nuclear thermal rockets share a number of similarities with terrestrial HTGRs and would be amenable to similar types of analyses. In these reactors, the heat transfer in the solid core mass is of primary interest in design and safety assessment. One significant safety feature of these reactors is the capability to withstand a loss of pressure and forced cooling in the primary system and still maintain peak fuel temperatures below the safe threshold for retaining the fission products. To accurately assess the performance of gas-cooled reactors during these types of transients, a Helium/Hydrogen Cooled Reactor Analysis (HERA) computer code has been developed. HERA has the ability to model arbitrary geometries in three dimensions, which allows the user to easily analyze reactor cores constructed of prismatic graphite elements. The code accounts for heat generation in the fuel, control rods and other structures; conduction and radiation across gaps; convection to the coolant; and a variety of boundary conditions. The numerical solution scheme has been optimized for vector computers, making long transient analyses economical. Time integration is either explicit or implicit, which allows the use of the model to accurately calculate both short- or long-term transients with an efficient use of computer time. Both the basic spatial and temporal integration schemes have been benchmarked against analytical solutions. Also, HERA has been used to analyze a depressurized loss of forced cooling transient in a HTGR with a very detailed three-dimensional input model. The results compare favorably with other means of analysis and provide further validation of the models and methods. 18 refs., 11 figs.

  20. Commercial-Scale Performance Predictions for High-Temperature Electrolysis Plants Coupled to Three Advanced Reactor Types

    SciTech Connect (OSTI)

    M. G. McKellar; J. E. O'Brien; J. S. Herring

    2007-09-01T23:59:59.000Z

    This report presents results of system analyses that have been developed to assess the hydrogen production performance of commercial-scale high-temperature electrolysis (HTE) plants driven by three different advanced reactor – power-cycle combinations: a high-temperature helium cooled reactor coupled to a direct Brayton power cycle, a supercritical CO2-cooled reactor coupled to a direct recompression cycle, and a sodium-cooled fast reactor coupled to a Rankine cycle. The system analyses were performed using UniSim software. The work described in this report represents a refinement of previous analyses in that the process flow diagrams include realistic representations of the three advanced reactors directly coupled to the power cycles and integrated with the high-temperature electrolysis process loops. In addition, this report includes parametric studies in which the performance of each HTE concept is determined over a wide range of operating conditions. Results of the study indicate that overall thermal-to- hydrogen production efficiencies (based on the low heating value of the produced hydrogen) in the 45 - 50% range can be achieved at reasonable production rates with the high-temperature helium cooled reactor concept, 42 - 44% with the supercritical CO2-cooled reactor and about 33 - 34% with the sodium-cooled reactor.

  1. Helium-3/Helium-4 Ratios in Soil Gas as an Indicator of Tritium Contamination Near the 618-11 Burial Ground, Hanford Site, Washington

    SciTech Connect (OSTI)

    Olsen, Khris B.; Dresel, P. Evan; Evans, J. C.; Poreda, Robert; Shin, Jang Soo

    2003-10-01T23:59:59.000Z

    This paper discusses how Pacific Northwest National Laboratory sampled and analyzed soil gas for helium-3 and helium-4 concentrations from the vicinity of the 618-11 burial ground.

  2. Trace determination of lead by helium-4 activation analysis 

    E-Print Network [OSTI]

    Vargas Bernal, Maria E.

    1984-01-01T23:59:59.000Z

    TRACE DETERMINATION OF LEAD BY HELIUM-4 ACTIVATION ANALYSIS A Thesis by MARIA E. VARGAS BERNAL Submitted to the Graduate College of Texas ARM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August... 1984 Major Subject: Chemistry TRACE DETERMINATION OF LEAD BY HELIUM-4 ACTIVATION ANALYSIS A Thesis by MARIA E. VARGAS BERNAL Approved as to style and format by: Emile A. Schweikert (Chairman of Committee) Marvin W. Rowe (Member) Gerald A. Sc...

  3. Trace determination of lead by helium-4 activation analysis

    E-Print Network [OSTI]

    Vargas Bernal, Maria E.

    1984-01-01T23:59:59.000Z

    TRACE DETERMINATION OF LEAD BY HELIUM-4 ACTIVATION ANALYSIS A Thesis by MARIA E. VARGAS BERNAL Submitted to the Graduate College of Texas ARM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August... 1984 Major Subject: Chemistry TRACE DETERMINATION OF LEAD BY HELIUM-4 ACTIVATION ANALYSIS A Thesis by MARIA E. VARGAS BERNAL Approved as to style and format by: Emile A. Schweikert (Chairman of Committee) Marvin W. Rowe (Member) Gerald A. Sc...

  4. Possible stimulation of nuclear alpha-decay by superfluid helium

    E-Print Network [OSTI]

    A. L. Barabanov

    2009-09-03T23:59:59.000Z

    It is suggested that superfluid helium (condensate of 4-He atoms) may stimulate nuclear alpha-decay in a situation when an alpha-emitter moves through superfluid helium with fine-tuned velocity, so that the backward-emitted alpha-particle is at rest in the laboratory frame. It is shown that the probability of stimulated alpha-decay in this case may be sizable enough to be detected.

  5. Process Options for Nominal 2-K Helium Refrigeration System Designs

    SciTech Connect (OSTI)

    Peter Knudsen, Venkatarao Ganni

    2012-07-01T23:59:59.000Z

    Nominal 2-K helium refrigeration systems are frequently used for superconducting radio frequency and magnet string technologies used in accelerators. This paper examines the trade-offs and approximate performance of four basic types of processes used for the refrigeration of these technologies; direct vacuum pumping on a helium bath, direct vacuum pumping using full or partial refrigeration recovery, cold compression, and hybrid compression (i.e., a blend of cold and warm sub-atmospheric compression).

  6. THE INTEGRATION OF PROCESS HEAT APPLICATIONS TO HIGH TEMPERATURE GAS REACTORS

    SciTech Connect (OSTI)

    Michael G. McKellar

    2011-11-01T23:59:59.000Z

    A high temperature gas reactor, HTGR, can produce industrial process steam, high-temperature heat-transfer gases, and/or electricity. In conventional industrial processes, these products are generated by the combustion of fossil fuels such as coal and natural gas, resulting in significant emissions of greenhouse gases such as carbon dioxide. Heat or electricity produced in an HTGR could be used to supply process heat or electricity to conventional processes without generating any greenhouse gases. Process heat from a reactor needs to be transported by a gas to the industrial process. Two such gases were considered in this study: helium and steam. For this analysis, it was assumed that steam was delivered at 17 MPa and 540 C and helium was delivered at 7 MPa and at a variety of temperatures. The temperature of the gas returning from the industrial process and going to the HTGR must be within certain temperature ranges to maintain the correct reactor inlet temperature for a particular reactor outlet temperature. The returning gas may be below the reactor inlet temperature, ROT, but not above. The optimal return temperature produces the maximum process heat gas flow rate. For steam, the delivered pressure sets an optimal reactor outlet temperature based on the condensation temperature of the steam. ROTs greater than 769.7 C produce no additional advantage for the production of steam.

  7. Superfluid helium cryogenic systems for superconducting RF cavities at KEK

    SciTech Connect (OSTI)

    Nakai, H.; Hara, K.; Honma, T.; Hosoyama, K.; Kojima, Y.; Nakanishi, K. [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0033 (Japan); Kanekiyo, T. [Hitachi Plant Technologies, Ltd., Toshima-ku, Tokyo 170-8466 (Japan); Morita, S. [Hitachi Plant Mechanics Co., Ltd., Kudamatsu, Yamaguchi 744-0061 (Japan)

    2014-01-29T23:59:59.000Z

    Recent accelerator projects at KEK, such as the Superconducting RF Test Facility (STF) for R and D of the International Linear Collider (ILC) project and the compact Energy Recovery Linac (cERL), employ superconducting RF cavities made of pure niobium, which can generate high gradient acceleration field. Since the operation temperature of these cavities is selected to be 2 K, we have developed two 2 K superfluid helium cryogenic systems for stable operation of superconducting RF cavities for each of STF and cERL. These two 2 K superfluid helium cryogenic systems are identical in principle. Since the operation mode of the cavities is different for STF and cERL, i.e. the pulse mode for STF and the continuous wave mode for cERL, the heat loads from the cavities are quite different. The 2 K superfluid helium cryogenic systems mainly consists of ordinary helium liquefiers/refrigerators, 2 K refrigerator cold boxes, helium gas pumping systems and high-performance transfer lines. The 2 K refrigerators and the high-performance transfer lines are designed by KEK. Some superconducting RF cavity cryomodules have been already connected to the 2 K superfluid helium cryogenic systems for STF and cERL respectively, and cooled down to 2 K successfully.

  8. A review of existing gas-cooled reactor circulators with application of the lessons learned to the new production reactor circulators

    SciTech Connect (OSTI)

    White, L.S.

    1990-07-01T23:59:59.000Z

    This report presents the results of a study of the lessons learned during the design, testing, and operation of gas-cooled reactor coolant circulators. The intent of this study is to identify failure modes and problem areas of the existing circulators so this information can be incorporated into the design of the circulators for the New Production Reactor (NPR)-Modular High-Temperature Gas Cooled Reactor (MHTGR). The information for this study was obtained primarily from open literature and includes data on high-pressure, high-temperature helium test loop circulators as well as the existing gas cooled reactors worldwide. This investigation indicates that trouble free circulator performance can only be expected when the design program includes a comprehensive prototypical test program, with the results of this test program factored into the final circulator design. 43 refs., 7 tabs.

  9. Helium-3/Helium-4 Ratios in Soil Gas as an Indicator of Tritium Contamination Near the 618-11 Burial Ground, Hanford Site, Washington

    SciTech Connect (OSTI)

    Olsen, Khris B.; Dresel, P Evan; Evans, J. C.; Poreda, Robert

    2004-10-09T23:59:59.000Z

    Pacific Northwest National Laboratory sampled and analyzed soil gas for helium-3 and helium-4 concentrations from the vicinity of the 618-11 burial ground. The results of the measurement of helium isotopes in soil gas provided a rapid and cost-effective technique to define the shape and extent of tritium contamination from the 618-11 burial ground.

  10. Classical Helium Atom with Radiation Reaction

    E-Print Network [OSTI]

    G. Camelio; A. Carati; L. Galgani

    2011-11-24T23:59:59.000Z

    We study a classical model of Helium atom in which, in addition to the Coulomb forces, the radiation reaction forces are taken into account. This modification brings in the model a new qualitative feature of a global character. Indeed, as pointed out by Dirac, in any model of classical electrodynamics of point particles involving radiation reaction one has to eliminate, from the a priori conceivable solutions of the problem, those corresponding to the emission of an infinite amount of energy. We show that the Dirac prescription solves a problem of inconsistency plaguing all available models which neglect radiation reaction, namely, the fact that in all such models most initial data lead to a spontaneous breakdown of the atom. A further modification is that the system thus acquires a peculiar form of dissipation. In particular, this makes attractive an invariant manifold of special physical interest, the zero--dipole manifold, that corresponds to motions in which no energy is radiated away (in the dipole approximation). We finally study numerically the invariant measure naturally induced by the time--evolution on such a manifold, and this corresponds to studying the formation process of the atom. Indications are given that such a measure may be singular with respect to that of Lebesgue.

  11. Anti-helium from Dark Matter annihilations

    E-Print Network [OSTI]

    Marco Cirelli; Nicolao Fornengo; Marco Taoso; Andrea Vittino

    2014-10-21T23:59:59.000Z

    Galactic Dark Matter (DM) annihilations can produce cosmic-ray anti-nuclei via the nuclear coalescence of the anti-protons and anti-neutrons originated directly from the annihilation process. Since anti-deuterons have been shown to offer a distinctive DM signal, with potentially good prospects of detection in large portions of the DM-particle parameter space, we explore here the production of heavier anti-nuclei, specifically anti-helium. Even more than for anti-deuterons, the DM-produced anti-He flux can be mostly prominent over the astrophysical anti-He background at low kinetic energies, typically below 3-5 GeV/n. However, the larger number of anti-nucleons involved in the formation process makes the anti-He flux extremely small. We therefore explore, for a few DM benchmark cases, whether the yield is sufficient to allow for anti-He detection in current-generation experiments, such as AMS-02. We account for the uncertainties due to the propagation in the Galaxy and to the uncertain details of the coalescence process, and we consider the constraints already imposed by anti-proton searches. We find that only for very optimistic configurations it might be possible to achieve detection with current generation detectors. We estimate that, in more realistic configurations, an increase in experimental sensitivity at low-kinetic energies of about a factor of 500-1000 would allow to start probing DM through the rare cosmic anti-He production.

  12. Reactor Sharing Program

    SciTech Connect (OSTI)

    Vernetson, W.G.

    1993-01-01T23:59:59.000Z

    Progress achieved at the University of Florida Training Reactor (UFTR) facility through the US Department of Energy's University Reactor Sharing Program is reported for the period of 1991--1992.

  13. Undergraduate reactor control experiment

    SciTech Connect (OSTI)

    Edwards, R.M.; Power, M.A.; Bryan, M. (Pennsylvania State Univ., University Park (United States))

    1992-01-01T23:59:59.000Z

    A sequence of reactor and related experiments has been a central element of a senior-level laboratory course at Pennsylvania State University (Penn State) for more than 20 yr. A new experiment has been developed where the students program and operate a computer controller that manipulates the speed of a secondary control rod to regulate TRIGA reactor power. Elementary feedback control theory is introduced to explain the experiment, which emphasizes the nonlinear aspect of reactor control where power level changes are equivalent to a change in control loop gain. Digital control of nuclear reactors has become more visible at Penn State with the replacement of the original analog-based TRIGA reactor control console with a modern computer-based digital control console. Several TRIGA reactor dynamics experiments, which comprise half of the three-credit laboratory course, lead to the control experiment finale: (a) digital simulation, (b) control rod calibration, (c) reactor pulsing, (d) reactivity oscillator, and (e) reactor noise.

  14. Attrition reactor system

    DOE Patents [OSTI]

    Scott, Charles D. (Oak Ridge, TN); Davison, Brian H. (Knoxvile, TN)

    1993-01-01T23:59:59.000Z

    A reactor vessel for reacting a solid particulate with a liquid reactant has a centrifugal pump in circulatory flow communication with the reactor vessel for providing particulate attrition, resulting in additional fresh surface where the reaction can occur.

  15. Attrition reactor system

    DOE Patents [OSTI]

    Scott, C.D.; Davison, B.H.

    1993-09-28T23:59:59.000Z

    A reactor vessel for reacting a solid particulate with a liquid reactant has a centrifugal pump in circulatory flow communication with the reactor vessel for providing particulate attrition, resulting in additional fresh surface where the reaction can occur. 2 figures.

  16. Helium transport and exhaust studies of H-mode discharges in the DIII-D tokamak

    SciTech Connect (OSTI)

    Hillis, D.L.; Wade, M.R.; Hogan, J.T. [Oak Ridge National Lab., TN (United States)] [and others

    1993-12-31T23:59:59.000Z

    A collaborative program has been initiated to measure helium (He) transport and exhaust on DIII-D in L-mode, ELM-free H-mode, and ELMing H-mode. These diverted plasmas operating in enhanced confinement regimes should provide valuable information for the International Thermonuclear Experimental Reactor (ITER). To simulate the presence of He ash in DIII-D, a 50 ms He puff is injected into a DIII-D plasma, resulting in a He concentration of {approximately} 15%. The time dependence of the He density profiles in the plasma core is measured with charge-exchange recombination spectroscopy and the He spatial distribution on the diverter floor is studied with an impurity monitor array. The dependence of core transport diffusivities as a function of ELM frequency have been studied and the first demonstration made of He exhaust from an H-mode plasma in a diverted tokamak. The exhaust rate of He from these ELMing H-mode plasmas appears to be within the acceptable range for a fusion reactor, like ITER, based on a measured value of {tau}*{sub He}/{tau}E {approx}14.

  17. Oxidation of PCEA nuclear graphite by low water concentrations in helium

    SciTech Connect (OSTI)

    Contescu, Cristian I [ORNL; Mee, Robert [University of Tennessee (UT); Wang, Peng [ORNL; Romanova, Anna V [University of Tennessee, Knoxville (UTK); Burchell, Timothy D [ORNL

    2014-10-01T23:59:59.000Z

    Accelerated oxidation tests were performed to determine kinetic parameters of the chronic oxidation reaction of PCEA graphite in contact with helium coolant containing low moisture concentrations in high temperature gas-cooled reactors. To the authors best knowledge such a study has not been done since the detailed analysis of reaction of H-451 graphite with steam [Velasquez, Hightower, Burnette, 1978]. Since that H-451 graphite is now unavailable, it is urgently needed to characterize chronic oxidation behavior of new graphite grades under qualification for gas-cooled reactors. The Langmuir-Hinshelwood mechanism of carbon oxidation by water results in a non-linear reaction rate expression, with at least six different parameters. They were determined in accelerated oxidation experiments that covered a large range of temperatures (800 to 1100 oC), and partial pressures of water (15 to 850 Pa) and hydrogen (30 to 150 Pa) and used graphite specimens thin enough (4 mm) in order to avoid diffusion effects. Data analysis employed a statistical method based on multiple likelihood estimation of parameters and simultaneous fitting of non-linear equations. The results show significant material-specific differences between graphite grades PCEA and H-451 which were attributed to microstructural dissimilarity of the two materials. It is concluded that kinetic data cannot be transferred from one graphite grade to another.

  18. Helium gas bubble trapped in liquid helium in high magnetic field

    SciTech Connect (OSTI)

    Bai, H., E-mail: bai@magnet.fsu.edu; Hannahs, S. T.; Markiewicz, W. D.; Weijers, H. W. [National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310 (United States)

    2014-03-31T23:59:59.000Z

    High magnetic field magnets are used widely in the area of the condensed matter physics, material science, chemistry, geochemistry, and biology at the National High Magnetic Field Laboratory. New high field magnets of state-of-the-art are being pursued and developed at the lab, such as the current developing 32?T, 32?mm bore fully superconducting magnet. Liquid Helium (LHe) is used as the coolant for superconducting magnets or samples tested in a high magnetic field. When the magnetic field reaches a relatively high value the boil-off helium gas bubble generated by heat losses in the cryostat can be trapped in the LHe bath in the region where BzdBz/dz is less than negative 2100 T{sup 2}/m, instead of floating up to the top of LHe. Then the magnet or sample in the trapped bubble region may lose efficient cooling. In the development of the 32?T magnet, a prototype Yttrium Barium Copper Oxide coil of 6 double pancakes with an inner diameter of 40?mm and an outer diameter of 140?mm was fabricated and tested in a resistive magnet providing a background field of 15?T. The trapped gas bubble was observed in the tests when the prototype coil was ramped up to 7.5?T at a current of 200?A. This letter reports the test results on the trapped gas bubble and the comparison with the analytical results which shows they are in a good agreement.

  19. Detection of significant differences between absorption spectra of neutral helium and low temperature photoionized helium plasmas

    SciTech Connect (OSTI)

    Bartnik, A.; Wachulak, P.; Fiedorowicz, H.; Fok, T.; Jarocki, R.; Szczurek, M. [Institute of Optoelectronics, Military University of Technology, Kaliskiego 2, 00-908 Warsaw (Poland)] [Institute of Optoelectronics, Military University of Technology, Kaliskiego 2, 00-908 Warsaw (Poland)

    2013-11-15T23:59:59.000Z

    In this work, spectral investigations of photoionized He plasmas were performed. The photoionized plasmas were created by irradiation of helium stream, with intense pulses from laser-plasma extreme ultraviolet (EUV) source. The EUV source was based on a double-stream Xe/Ne gas-puff target irradiated with 10 ns/10 J Nd:YAG laser pulses. The most intense emission from the source spanned a relatively narrow spectral region below 20 nm, however, spectrally integrated intensity at longer wavelengths was also significant. The EUV radiation was focused onto a gas stream, injected into a vacuum chamber synchronously with the EUV pulse. The long-wavelength part of the EUV radiation was used for backlighting of the photoionized plasmas to obtain absorption spectra. Both emission and absorption spectra in the EUV range were investigated. Significant differences between absorption spectra acquired for neutral helium and low temperature photoionized plasmas were demonstrated for the first time. Strong increase of intensities and spectral widths of absorption lines, together with a red shift of the K-edge, was shown.

  20. Advanced Test Reactor Tour

    SciTech Connect (OSTI)

    Miley, Don

    2011-01-01T23:59:59.000Z

    The Advanced Test Reactor at Idaho National Laboratory is the foremost nuclear materials test reactor in the world. This virtual tour describes the reactor, how experiments are conducted, and how spent nuclear fuel is handled and stored. For more information about INL research, visit http://www.facebook.com/idahonationallaboratory.

  1. High solids fermentation reactor

    DOE Patents [OSTI]

    Wyman, Charles E.; Grohmann, Karel; Himmel, Michael E.; Richard, Christopher J.

    1993-03-02T23:59:59.000Z

    A fermentation reactor and method for fermentation of materials having greater than about 10% solids. The reactor includes a rotatable shaft along the central axis, the shaft including rods extending outwardly to mix the materials. The reactor and method are useful for anaerobic digestion of municipal solid wastes to produce methane, for production of commodity chemicals from organic materials, and for microbial fermentation processes.

  2. High solids fermentation reactor

    DOE Patents [OSTI]

    Wyman, Charles E. (Lakewood, CO); Grohmann, Karel (Littleton, CO); Himmel, Michael E. (Littleton, CO); Richard, Christopher J. (Lakewood, CO)

    1993-01-01T23:59:59.000Z

    A fermentation reactor and method for fermentation of materials having greater than about 10% solids. The reactor includes a rotatable shaft along the central axis, the shaft including rods extending outwardly to mix the materials. The reactor and method are useful for anaerobic digestion of municipal solid wastes to produce methane, for production of commodity chemicals from organic materials, and for microbial fermentation processes.

  3. Improved vortex reactor system

    DOE Patents [OSTI]

    Diebold, James P. (Lakewood, CO); Scahill, John W. (Evergreen, CO)

    1995-01-01T23:59:59.000Z

    An improved vortex reactor system for affecting fast pyrolysis of biomass and Refuse Derived Fuel (RDF) feed materials comprising: a vortex reactor having its axis vertically disposed in relation to a jet of a horizontally disposed steam ejector that impels feed materials from a feeder and solids from a recycle loop along with a motive gas into a top part of said reactor.

  4. Advanced Test Reactor Tour

    ScienceCinema (OSTI)

    Miley, Don

    2013-05-28T23:59:59.000Z

    The Advanced Test Reactor at Idaho National Laboratory is the foremost nuclear materials test reactor in the world. This virtual tour describes the reactor, how experiments are conducted, and how spent nuclear fuel is handled and stored. For more information about INL research, visit http://www.facebook.com/idahonationallaboratory.

  5. Neutron behavior, reactor control, and reactor heat transfer. Volume four

    SciTech Connect (OSTI)

    Not Available

    1986-01-01T23:59:59.000Z

    Volume four covers neutron behavior (neutron absorption, how big are nuclei, neutron slowing down, neutron losses, the self-sustaining reactor), reactor control (what is controlled in a reactor, controlling neutron population, is it easy to control a reactor, range of reactor control, what happens when the fuel burns up, controlling a PWR, controlling a BWR, inherent safety of reactors), and reactor heat transfer (heat generation in a nuclear reactor, how is heat removed from a reactor core, heat transfer rate, heat transfer properties of the reactor coolant).

  6. Fuel-Cycle and Nuclear Material Disposition Issues Associated with High-Temperature Gas Reactors

    SciTech Connect (OSTI)

    Shropshire, D.E.; Herring, J.S.

    2004-10-03T23:59:59.000Z

    The objective of this paper is to facilitate a better understanding of the fuel-cycle and nuclear material disposition issues associated with high-temperature gas reactors (HTGRs). This paper reviews the nuclear fuel cycles supporting early and present day gas reactors, and identifies challenges for the advanced fuel cycles and waste management systems supporting the next generation of HTGRs, including the Very High Temperature Reactor, which is under development in the Generation IV Program. The earliest gas-cooled reactors were the carbon dioxide (CO2)-cooled reactors. Historical experience is available from over 1,000 reactor-years of operation from 52 electricity-generating, CO2-cooled reactor plants that were placed in operation worldwide. Following the CO2 reactor development, seven HTGR plants were built and operated. The HTGR came about from the combination of helium coolant and graphite moderator. Helium was used instead of air or CO2 as the coolant. The helium gas has a significant technical base due to the experience gained in the United States from the 40-MWe Peach Bottom and 330-MWe Fort St. Vrain reactors designed by General Atomics. Germany also built and operated the 15-MWe Arbeitsgemeinschaft Versuchsreaktor (AVR) and the 300-MWe Thorium High-Temperature Reactor (THTR) power plants. The AVR, THTR, Peach Bottom and Fort St. Vrain all used fuel containing thorium in various forms (i.e., carbides, oxides, thorium particles) and mixtures with highly enriched uranium. The operational experience gained from these early gas reactors can be applied to the next generation of nuclear power systems. HTGR systems are being developed in South Africa, China, Japan, the United States, and Russia. Elements of the HTGR system evaluated included fuel demands on uranium ore mining and milling, conversion, enrichment services, and fuel fabrication; fuel management in-core; spent fuel characteristics affecting fuel recycling and refabrication, fuel handling, interim storage, packaging, transportation, waste forms, waste treatment, decontamination and decommissioning issues; and low-level waste (LLW) and high-level waste (HLW) disposal.

  7. HTGR (High Temperature Gas-Cooled Reactor) ingress analysis using MINET

    SciTech Connect (OSTI)

    Van Tuyle, G.J.; Yang, J.W.; Kroeger, P.G.; Mallen, A.N.; Aronson, A.L.

    1989-04-01T23:59:59.000Z

    Modeling of water/steam ingress into the primary (helium) cooling circuit of a High Temperature Gas-Cooled Reactor (HTGR) is described. This modeling was implemented in the MINET Code, which is a program for analyzing transients in intricate fluid flow and heat transfer networks. Results from the simulation of a water ingress event postulated for the Modular HTGR are discussed. 27 refs., 6 figs., 6 tabs.

  8. Reactor vessel support system

    DOE Patents [OSTI]

    Golden, Martin P. (Trafford, PA); Holley, John C. (McKeesport, PA)

    1982-01-01T23:59:59.000Z

    A reactor vessel support system includes a support ring at the reactor top supported through a box ring on a ledge of the reactor containment. The box ring includes an annular space in the center of its cross-section to reduce heat flow and is keyed to the support ledge to transmit seismic forces from the reactor vessel to the containment structure. A coolant channel is provided at the outside circumference of the support ring to supply coolant gas through the keyways to channels between the reactor vessel and support ledge into the containment space.

  9. Asteroseismic determination of helium abundance in stellar envelopes

    E-Print Network [OSTI]

    Sarbani Basu; Anwesh Mazumdar; H. M Antia; Pierre Demarque

    2004-02-15T23:59:59.000Z

    Intermediate degree modes of the solar oscillations have previously been used to determine the solar helium abundance to a high degree of precision. However, we cannot expect to observe such modes in other stars. In this work we investigate whether low degree modes that should be available from space-based asteroseismology missions can be used to determine the helium abundance, Y, in stellar envelopes with sufficient precision. We find that the oscillatory signal in the frequencies caused by the depression in \\Gamma_1 in the second helium ionisation zone can be used to determine the envelope helium abundance of low mass main sequence stars. For frequency errors of 1 part in 10^4, we expect errors \\sigma_Y in the estimated helium abundance to range from 0.03 for 0.8M_sun stars to 0.01 for 1.2M_sun stars. The task is more complicated in evolved stars, such as subgiants, but is still feasible if the relative errors in the frequencies are less than 10^{-4}.

  10. Reactor water cleanup system

    DOE Patents [OSTI]

    Gluntz, D.M.; Taft, W.E.

    1994-12-20T23:59:59.000Z

    A reactor water cleanup system includes a reactor pressure vessel containing a reactor core submerged in reactor water. First and second parallel cleanup trains are provided for extracting portions of the reactor water from the pressure vessel, cleaning the extracted water, and returning the cleaned water to the pressure vessel. Each of the cleanup trains includes a heat exchanger for cooling the reactor water, and a cleaner for cleaning the cooled reactor water. A return line is disposed between the cleaner and the pressure vessel for channeling the cleaned water thereto in a first mode of operation. A portion of the cooled water is bypassed around the cleaner during a second mode of operation and returned through the pressure vessel for shutdown cooling. 1 figure.

  11. Spinning fluids reactor

    SciTech Connect (OSTI)

    Miller, Jan D; Hupka, Jan; Aranowski, Robert

    2012-11-20T23:59:59.000Z

    A spinning fluids reactor, includes a reactor body (24) having a circular cross-section and a fluid contactor screen (26) within the reactor body (24). The fluid contactor screen (26) having a plurality of apertures and a circular cross-section concentric with the reactor body (24) for a length thus forming an inner volume (28) bound by the fluid contactor screen (26) and an outer volume (30) bound by the reactor body (24) and the fluid contactor screen (26). A primary inlet (20) can be operatively connected to the reactor body (24) and can be configured to produce flow-through first spinning flow of a first fluid within the inner volume (28). A secondary inlet (22) can similarly be operatively connected to the reactor body (24) and can be configured to produce a second flow of a second fluid within the outer volume (30) which is optionally spinning.

  12. Determining Reactor Neutrino Flux

    E-Print Network [OSTI]

    Jun Cao

    2012-03-08T23:59:59.000Z

    Flux is an important source of uncertainties for a reactor neutrino experiment. It is determined from thermal power measurements, reactor core simulation, and knowledge of neutrino spectra of fuel isotopes. Past reactor neutrino experiments have determined the flux to (2-3)% precision. Precision measurements of mixing angle $\\theta_{13}$ by reactor neutrino experiments in the coming years will use near-far detector configurations. Most uncertainties from reactor will be canceled out. Understanding of the correlation of uncertainties is required for $\\theta_{13}$ experiments. Precise determination of reactor neutrino flux will also improve the sensitivity of the non-proliferation monitoring and future reactor experiments. We will discuss the flux calculation and recent progresses.

  13. Assessment of passive decay heat removal in the General Atomics Modular Helium Reactor

    E-Print Network [OSTI]

    Cocheme, Francois Guilhem

    2005-02-17T23:59:59.000Z

    incentive is to separate the two plants enough for the hydrogen plant to be considered outside of the nuclear plant influence. The radioactivity level on the chemical side must be sufficiently low to avoid classifying the hydrogen production plant as a...

  14. Focal depth measurement of scanning helium ion microscope

    SciTech Connect (OSTI)

    Guo, Hongxuan, E-mail: Guo.hongxuan@nims.go.jp [Global Research Center for Environment and Energy based on Nanomaterials Science, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Itoh, Hiroshi; Wang, Chunmei [Active State Technology Research Group, Research Institute of Instrumentation Frontier, National Institute of Advanced Industrial Science and Technology (AIST), 1-1 Umezono 1-Chome, Tsukuba, Ibaraki 305-8568 (Japan); Zhang, Han; Fujita, Daisuke [Nano Characterization Unit, Advanced Key Technologies Division, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

    2014-07-14T23:59:59.000Z

    When facing the challenges of critical dimension measurement of complicated nanostructures, such as of the three dimension integrated circuit, characterization of the focal depth of microscopes is important. In this Letter, we developed a method for characterizing the focal depth of a scanning helium ion microscope (HIM) by using an atomic force microscope tip characterizer (ATC). The ATC was tilted in a sample chamber at an angle to the scanning plan. Secondary electron images (SEIs) were obtained at different positions of the ATC. The edge resolution of the SEIs shows the nominal diameters of the helium ion beam at different focal levels. With this method, the nominal shapes of the helium ion beams were obtained with different apertures. Our results show that a small aperture is necessary to get a high spatial resolution and high depth of field images with HIM. This work provides a method for characterizing and improving the performance of HIM.

  15. Fast production of Bose-Einstein condensates of metastable Helium

    E-Print Network [OSTI]

    Bouton, Q; Hoendervanger, A L; Nogrette, F; Aspect, A; Westbrook, C I; Clément, D

    2015-01-01T23:59:59.000Z

    We report on the Bose-Einstein condensation of metastable Helium-4 atoms using a hybrid approach, consisting of a magnetic quadrupole and a crossed optical dipole trap. In our setup we cross the phase transition with 2x10^6 atoms, and we obtain pure condensates of 5x10^5 atoms in the optical trap. This novel approach to cooling Helium-4 provides enhanced cycle stability, large optical access to the atoms and results in production of a condensate every 6 seconds - a factor 3 faster than the state-of-the-art. This speed-up will dramatically reduce the data acquisition time needed for the measurement of many particle correlations, made possible by the ability of metastable Helium to be detected individually.

  16. Spin-based quantum computing using electrons on liquid helium

    E-Print Network [OSTI]

    S. A. Lyon

    2006-11-17T23:59:59.000Z

    Numerous physical systems have been proposed for constructing quantum computers, but formidable obstacles stand in the way of making even modest systems with a few hundred quantum bits (qubits). Several approaches utilize the spin of an electron as the qubit. Here it is suggested that the spin of electrons floating on the surface of liquid helium will make excellent qubits. These electrons can be electrostatically held and manipulated much like electrons in semiconductor heterostructures, but being in a vacuum the spins on helium suffer much less decoherence. In particular, the spin orbit interaction is reduced so that moving the qubits with voltages applied to gates has little effect on their coherence. Remaining sources of decoherence are considered and it is found that coherence times for electron spins on helium can be expected to exceed 100 s. It is shown how to obtain a controlled-NOT operation between two qubits using the magnetic dipole-dipole interaction.

  17. Helium and mercury in the central Seward Peninsula

    SciTech Connect (OSTI)

    Wescott, E.; Ruscetta, C.A.; Foley, D. (eds.)

    1981-05-01T23:59:59.000Z

    The central Seward Peninsula, Alaska, has one Known Geothermal Resource Area (KGRA) at Pilgrim Springs, and has recent volcanic flows, fault systems, topographic and tectonic features which can be explained by a rift model. As part of a geothermal reconnaissance of the area we used helium and mercury concentrations in soil as indicators of geothermal resources. The largest helium concentrations were found in the vicinity of the Pilgrims Springs KGRA, and indicate prime drilling sites. Five profile lines were run across the suspected rift system. Significant helium anomalies were found on several of the traverses, where future exploration might be concentrated. Mercury values showed a great range of variability on the traverses, and seem unreliable as geothermal indicators except in the vicinity of the Pilgrim Springs. Permafrost at the surface resulting in variations in sampling depth may contribute to the mercury variations.

  18. Two phase coexistence for the hydrogen-helium mixture

    E-Print Network [OSTI]

    Fantoni, Riccardo

    2015-01-01T23:59:59.000Z

    We use our newly constructed quantum Gibbs ensemble Monte Carlo algorithm to perform computer experiments for the two phase coexistence of a hydrogen-helium mixture. Our results are in quantitative agreement with the experimental results of C. M. Sneed, W. B. Streett, R. E. Sonntag, and G. J. Van Wylen. The difference between our results and the experimental ones is in all cases less than 15% relative to the experiment, reducing to less than 5% in the low helium concentration phase. At the gravitational inversion between the vapor and the liquid phase, at low temperatures and high pressures, the quantum effects become relevant. At extremely low temperature and pressure the first component to show superfluidity is the helium in the vapor phase.

  19. Re-Condensation and Liquefaction of Helium and Hydrogen Using Coolers

    E-Print Network [OSTI]

    Green, Michael A.

    2010-01-01T23:59:59.000Z

    AND LIQUEFACTION OF HELIUM AND HYDROGEN USING COOLERS M. A.liquefaction for helium and hydrogen can occur. KEYWORDS:each contain a liquid hydrogen absorber [4] that is cooled

  20. Non-Sticking of Helium Buffer Gas to Hydrocarbons

    E-Print Network [OSTI]

    Croft, James F E

    2014-01-01T23:59:59.000Z

    Lifetimes of complexes formed during helium-hydrocarbon collisions at low temperature are estimated for symmetric top hydrocarbons. The lifetimes are obtained using a density-of-states approach. In general the lifetimes are less than 10-100 ns, and are found to decrease with increasing hydrocarbon size. This suggests that clustering will not limit precision spectroscopy in helium buffer gas experiments. Lifetimes are computed for noble-gas benzene collisions and are found to be in reasonable agreement with lifetimes obtained from classical trajectories as reported by Cui {\\it et al}.

  1. $?^4$ Ry corrections to singlet states of helium

    E-Print Network [OSTI]

    Krzysztof Pachucki

    2006-07-07T23:59:59.000Z

    Corrections of order $\\alpha^4$Ry are calculated for the singlet states $1^1S_0$ and $2^1S_0$ of the helium atom. The result for $1^1S_0$ state is in slight disagreement with that of Korobov and Yelkhovsky in [Phys. Rev. Lett. {\\bf 87}, 193003 (2001)]. The results obtained lead to a significant improvement of transition frequencies between low lying levels of the helium atom. In particular theoretical predictions for the $2^1S_0 - 1^1S_0$ transition are found to be in disagreement with experimental values.

  2. Electron scattering in helium for Monte Carlo simulations

    SciTech Connect (OSTI)

    Khrabrov, Alexander V.; Kaganovich, Igor D. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2012-09-15T23:59:59.000Z

    An analytical approximation for differential cross-section of electron scattering on helium atoms is introduced. It is intended for Monte Carlo simulations, which, instead of angular distributions based on experimental data (or on first-principle calculations), usually rely on approximations that are accurate yet numerically efficient. The approximation is based on the screened-Coulomb differential cross-section with energy-dependent screening. For helium, a two-pole approximation of the screening parameter is found to be highly accurate over a wide range of energies.

  3. Cavitation Density of Superfluid Helium-4 around 1 K

    E-Print Network [OSTI]

    An Qu; Azer Trimeche; Jacques Dupont-roc; Jules Grucker; Philippe Jacquier

    2015-04-14T23:59:59.000Z

    Using an optical interferomertric method, the homogeneous cavitation density of superfluid helium at $T=0.96\\,$K is measured and found to be $\\rho_{cav}=0.1338\\pm0.0002\\rm\\,g.cm^{-3}$. A well established equation of state for liquid helium at negative pressures converts this to the cavitation pressure $P_{cav}=-5.1\\pm0.1\\,$bar. This cavitation pressure is consistent with a model taking into account the presence of quantized vortices, but disagrees with previously published experimental values of $P_{cav}$.

  4. Detection and Imaging of He_2 Molecules in Superfluid Helium

    E-Print Network [OSTI]

    W. G. Rellergert; S. B. Cahn; A. Garvan; J. C. Hanson; W. H. Lippincott; J. A. Nikkel; D. N. McKinsey

    2007-12-18T23:59:59.000Z

    We present data that show a cycling transition can be used to detect and image metastable He$_2$ triplet molecules in superfluid helium. We demonstrate that limitations on the cycling efficiency due to the vibrational structure of the molecule can be mitigated by the use of repumping lasers. Images of the molecules obtained using the method are also shown. This technique gives rise to a new kind of ionizing radiation detector. The use of He$_2$ triplet molecules as tracer particles in the superfluid promises to be a powerful tool for visualization of both quantum and classical turbulence in liquid helium.

  5. Material Mixing of Tungsten with Carbon and Helium

    SciTech Connect (OSTI)

    Ueda, Y.; Lee, H. T. [Graduate School of Engineering, Osaka University, 2-1 Yamada-Oka, Suita, Osaka 565-0871 (Japan)

    2010-05-20T23:59:59.000Z

    In ITER, graphite and tungsten are used for divertor materials and are mixed through erosion, transport, and redeposition. Helium, a fusion reactant, is an intrinsic element in fusion plasmas that impinges on the metallic wall materials to form He bubbles. W-C mixed layers and He bubble layers greatly affect tritium retention. In this paper, impacts of W-C material mixing on erosion and hydrogen isotope retention are reviewed. Then, recent results on carbon deposition on tungsten in TEXTOR tokamak and helium effects on blistering and retention are discussed.

  6. Spectroscopy of barium atoms in liquid and solid helium matrices

    SciTech Connect (OSTI)

    Lebedev, V.; Moroshkin, P.; Weis, A. [Departement de Physique, Universite de Fribourg, Chemin du Musee 3, CH-1700 Fribourg (Switzerland)

    2011-08-15T23:59:59.000Z

    We present an exhaustive overview of optical absorption and laser-induced fluorescence lines of Ba atoms in liquid and solid helium matrices in visible and near-infrared spectral ranges. Due to the increased density of isolated atoms, we have found a large number of spectral lines that were not observed in condensed helium matrices before. We have also measured the lifetimes of metastable states. The lowest {sup 3}D{sub 1} metastable state has lifetime of 2.6 s and can be used as an intermediate state in two-step excitations of high-lying states. Various matrix-induced radiationless population transfer channels have been identified.

  7. Helium Jet-Cooled Tungsten Divertor Concept J.S. O'Della

    E-Print Network [OSTI]

    Raffray, A. René

    Helium Jet-Cooled Tungsten Divertor Concept J.S. O'Della and A.R. Raffrayb a Plasma Processes, Inc., Huntsville, Alabama, USA b University of California ­ San Diego, La Jolla, California, USA Abstract-- Helium helium cooling techniques for high heat flux (HHF) applications. However, because of the small size

  8. Chapter 11 HELIUM-COOLED REFRACTORY ALLOYS FIRST WALL AND BLANKET EVALUATION

    E-Print Network [OSTI]

    California at Los Angeles, University of

    1 Chapter 11 HELIUM-COOLED REFRACTORY ALLOYS FIRST WALL AND BLANKET EVALUATION 11.1 Introduction performed thermal hydraulics, nuclear, activation and safety designs and analysis. High-pressure helium of the refractory alloy helium-cooled breeder FW/blanket concept developed under the APEX program is presented

  9. ccsd-00000262(version1):26Mar2003 Looking back at superfluid helium

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ccsd-00000262(version1):26Mar2003 Looking back at superfluid helium S´ebastien Balibar Laboratoire condensation in several gases, it is interesting to look back at some properties of superfluid helium. After and vortices in the existence of a critical velocity in superfluid helium. I finally discuss the existence

  10. Helium corona-assisted air discharge Nan Jiang, Lei Gao, Ailing Ji, and Zexian Caoa)

    E-Print Network [OSTI]

    Zexian, Cao

    Helium corona-assisted air discharge Nan Jiang, Lei Gao, Ailing Ji, and Zexian Caoa) Institute of non-thermal plasmas. By taking advantage of the low onset voltage for helium corona, air discharge was successfully launched at much reduced voltages with a needle-plate system partly contained in a helium

  11. The Helium Logging Facility Jurriaan Hage (jur@cs.uu.nl)

    E-Print Network [OSTI]

    Utrecht, Universiteit

    The Helium Logging Facility Jurriaan Hage (jur@cs.uu.nl) institute of information and computing sciences, utrecht university technical report UU-CS-2005-055 www.cs.uu.nl #12;Abstract Helium is a compiler experiences in using socket communication for the purpose. 1 #12;1 Introduction The Helium compiler implements

  12. Heat and Metal Transfer in Gas Metal Arc Welding Using Argon and Helium

    E-Print Network [OSTI]

    Eagar, Thomas W.

    Heat and Metal Transfer in Gas Metal Arc Welding Using Argon and Helium P.G. JONSSON, T.W. EAGAR transfer in gas metal arc welding (GMAW) of mild steel using argon and helium shielding gases. Major dif properties. Various findings from the study include that an arc cannot be stru~k in a pure helium atmosphere

  13. Physics 216 Spring 2012 The Variational Computation of the Ground State Energy of Helium

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    Physics 216 Spring 2012 The Variational Computation of the Ground State Energy of Helium I. Introduction to the variational computation The Hamiltonian for the two­electron system of the helium atom is principle to compute the ground state energy of the helium atom. The ground state wave function

  14. Mantle helium reveals Southern Ocean hydrothermal venting Gisela Winckler,1,2

    E-Print Network [OSTI]

    Winckler, Gisela

    Click Here for Full Article Mantle helium reveals Southern Ocean hydrothermal venting Gisela the distribution of helium isotopes along an oceanic transect at 67°S to identify previously unobserved provided by the helium isotope anomaly with independent hydrographic information from the Southern Ocean

  15. Optical Measurement of the Non-linear Focusing of Sound in Liquid Helium 4

    E-Print Network [OSTI]

    Caupin, Frédéric

    Optical Measurement of the Non-linear Focusing of Sound in Liquid Helium 4 X. Chavanne, S. Balibar have measured the amplitude of 1MHz acoustic waves focused in liquid helium 4. Our resolution is 10 the reflec- tion of light at the glass/helium interface, which depends on the refractive index of the liquid

  16. Helium Isotopic Textures in Earth's Upper Mantle David W. Graham a

    E-Print Network [OSTI]

    Graham, David W.

    Helium Isotopic Textures in Earth's Upper Mantle David W. Graham a , Barry B. Hanan b , Christophe of variability represent a description of helium isotopic texture. We utilize four complementary methods (~100 km) mantle flow, and by sampling during the partial melting process (~30 km). Keywords: helium

  17. Improved helium exchange gas cryostat and sample tube designs for automated gas sampling and cryopumping

    E-Print Network [OSTI]

    Severinghaus, Jeffrey P.

    Improved helium exchange gas cryostat and sample tube designs for automated gas sampling, California 92093-0244, USA [1] In order to eliminate the use of liquid helium for the extraction of atmospheric gases from polar ice cores, two units of a redesigned top load helium exchange gas cryostat were

  18. LOCAL PROBE IN A RAYLEIGH-BENARD EXPERIMENT IN LIQUID HELIUM

    E-Print Network [OSTI]

    Boyer, Edmond

    L-369 LOCAL PROBE IN A RAYLEIGH-BENARD EXPERIMENT IN LIQUID HELIUM A. LIBCHABER and J. MAURER. Abstract. 2014 We have measured, in a Rayleigh-Benard experiment in liquid helium, the time dependent-Benard experiment in liquid helium, using for the first time a local probe. Time dependent effects above

  19. Helium, for Learning Haskell Bastiaan Heeren Daan Leijen Arjan van IJzendoorn

    E-Print Network [OSTI]

    Heeren, Bastiaan

    Helium, for Learning Haskell Bastiaan Heeren Daan Leijen Arjan van IJzendoorn Institute {bastiaan, daan, afie}@cs.uu.nl Abstract Helium is a user-friendly compiler designed especially for learn concern both in the choice of the language features and in the implementation of the compiler. Helium

  20. Physics 139B Fall 2009 The Variational Computation of the Ground State Energy of Helium

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    Physics 139B Fall 2009 The Variational Computation of the Ground State Energy of Helium I. Introduction to the variational computation The Hamiltonian for the two­electron system of the helium atom is principle to compute the ground state energy of the helium atom. The ground state wave function

  1. Displaced helium and carbon in the Hawaiian plume Albrecht W. Hofmann a,b,

    E-Print Network [OSTI]

    Farnetani, Cinzia G.

    Displaced helium and carbon in the Hawaiian plume Albrecht W. Hofmann a,b, , Cinzia G. Farnetani c 2011 Available online 1 November 2011 Editor: Y. Ricard Keywords: mantle plumes Hawaii helium vertically due to its low density and viscosity and is thus displaced from the plume center. Helium

  2. Improved vortex reactor system

    DOE Patents [OSTI]

    Diebold, J.P.; Scahill, J.W.

    1995-05-09T23:59:59.000Z

    An improved vortex reactor system is described for affecting fast pyrolysis of biomass and Refuse Derived Fuel (RDF) feed materials comprising: a vortex reactor having its axis vertically disposed in relation to a jet of a horizontally disposed steam ejector that impels feed materials from a feeder and solids from a recycle loop along with a motive gas into a top part of said reactor. 12 figs.

  3. Resonant charge-exchange involving excited helium atoms and reactive transport of local thermodynamic equilibrium helium plasma

    SciTech Connect (OSTI)

    Kosarim, A. V.; Smirnov, B. M. [Joint Institute for High Temperatures RAS, Moscow (Russian Federation); Laricchiuta, A. [CNR IMIP Bari, Bari (Italy); Capitelli, M. [CNR IMIP Bari, Bari (Italy); Department of Chemistry, University of Bari, Bari (Italy)

    2012-06-15T23:59:59.000Z

    The cross sections for charge-exchange and charge-transfer processes are evaluated for collisions of helium ions with parent-atoms in ground and excited states, with the principal quantum number n= 1-5, in the collision energy range from thermal up to 10 eV. Corresponding diffusion-type collision integrals are derived, and the role of 'abnormal' transport of electronically excited states on the reactive thermal conductivity of equilibrium helium plasma, at atmospheric pressure, estimated in the frame of a simplified approach.

  4. Tokamak reactor first wall

    DOE Patents [OSTI]

    Creedon, R.L.; Levine, H.E.; Wong, C.; Battaglia, J.

    1984-11-20T23:59:59.000Z

    This invention relates to an improved first wall construction for a tokamak fusion reactor vessel, or other vessels subjected to similar pressure and thermal stresses.

  5. Pressurized fluidized bed reactor

    DOE Patents [OSTI]

    Isaksson, Juhani (Karhula, FI)

    1996-01-01T23:59:59.000Z

    A pressurized fluid bed reactor power plant includes a fluidized bed reactor contained within a pressure vessel with a pressurized gas volume between the reactor and the vessel. A first conduit supplies primary gas from the gas volume to the reactor, passing outside the pressure vessel and then returning through the pressure vessel to the reactor, and pressurized gas is supplied from a compressor through a second conduit to the gas volume. A third conduit, comprising a hot gas discharge, carries gases from the reactor, through a filter, and ultimately to a turbine. During normal operation of the plant, pressurized gas is withdrawn from the gas volume through the first conduit and introduced into the reactor at a substantially continuously controlled rate as the primary gas to the reactor. In response to an operational disturbance of the plant, the flow of gas in the first, second, and third conduits is terminated, and thereafter the pressure in the gas volume and in the reactor is substantially simultaneously reduced by opening pressure relief valves in the first and third conduits, and optionally by passing air directly from the second conduit to the turbine.

  6. Pressurized fluidized bed reactor

    DOE Patents [OSTI]

    Isaksson, J.

    1996-03-19T23:59:59.000Z

    A pressurized fluid bed reactor power plant includes a fluidized bed reactor contained within a pressure vessel with a pressurized gas volume between the reactor and the vessel. A first conduit supplies primary gas from the gas volume to the reactor, passing outside the pressure vessel and then returning through the pressure vessel to the reactor, and pressurized gas is supplied from a compressor through a second conduit to the gas volume. A third conduit, comprising a hot gas discharge, carries gases from the reactor, through a filter, and ultimately to a turbine. During normal operation of the plant, pressurized gas is withdrawn from the gas volume through the first conduit and introduced into the reactor at a substantially continuously controlled rate as the primary gas to the reactor. In response to an operational disturbance of the plant, the flow of gas in the first, second, and third conduits is terminated, and thereafter the pressure in the gas volume and in the reactor is substantially simultaneously reduced by opening pressure relief valves in the first and third conduits, and optionally by passing air directly from the second conduit to the turbine. 1 fig.

  7. DOE reactor-pumped laser program

    SciTech Connect (OSTI)

    Felty, J.R. [USDOE, Germantown, MD (United States). Defense Programs; Lipinski, R.J.; McArthur, D.A.; Pickard, P.S. [Sandia National Labs., Albuquerque, NM (United States)

    1993-12-31T23:59:59.000Z

    FALCON is a high-power, steady-state, nuclear reactor-pumped laser (RPL) concept that is being developed by the Department of Energy. The FALCON program has experimentally demonstrated reactor-pumped lasing in various mixtures of xenon, argon, neon, and helium at at wavelengths of 585, 703, 725, 1271, 1733, 1792, 2032, 2630, 2650, and 3370 nm with intrinsic efficiency as high as 2.5%. The major strengths of a reactor-pumped laser are continuous high-power operation, modular construction, self-contained power, compact size, and a variety of wavelengths (from visible to infrared). These characteristics suggest numerous applications not easily accessible to other laser types. A ground-based RPL could beam its power to space for such activities as illuminating geosynchronous communication satellites in the earth`s shadow to extend their lives, beaming power to orbital transfer vehicles, removing space debris, and providing power (from earth) to a lunar base during the long lunar night. The compact size and self-contained power also makes an RPL very suitable for ship basing so that power-beaming activities could be situated around the globe. The continuous high power of an RPL opens many potential manufacturing applications such as deep-penetration welding and cutting of thick structures, wide-area hardening of metal surfaces by heat treatment or cladding application, wide-area vapor deposition of ceramics onto metal surfaces, production of sub-micron sized particles for manufacturing of ceramics, wide-area deposition of diamond-like coatings, and 3-D ceramic lithography.

  8. PULSATIONS IN HYDROGEN BURNING LOW-MASS HELIUM WHITE DWARFS

    SciTech Connect (OSTI)

    Steinfadt, Justin D. R. [Department of Physics, Broida Hall, University of California, Santa Barbara, CA 93106 (United States); Bildsten, Lars [Kavli Institute for Theoretical Physics and Department of Physics, Kohn Hall, University of California, Santa Barbara, CA 93106 (United States); Arras, Phil, E-mail: jdrs@physics.ucsb.ed, E-mail: bildsten@kitp.ucsb.ed, E-mail: arras@virginia.ed [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States)

    2010-07-20T23:59:59.000Z

    Helium core white dwarfs (WDs) with mass M {approx}< 0.20 M {sub sun} undergo several Gyr of stable hydrogen burning as they evolve. We show that in a certain range of WD and hydrogen envelope masses, these WDs may exhibit g-mode pulsations similar to their passively cooling, more massive carbon/oxygen core counterparts, the ZZ Cetis. Our models with stably burning hydrogen envelopes on helium cores yield g-mode periods and period spacings longer than the canonical ZZ Cetis by nearly a factor of 2. We show that core composition and structure can be probed using seismology since the g-mode eigenfunctions predominantly reside in the helium core. Though we have not carried out a fully nonadiabatic stability analysis, the scaling of the thermal time in the convective zone with surface gravity highlights several low-mass helium WDs that should be observed in search of pulsations: NLTT 11748, SDSS J0822+2753, and the companion to PSR J1012+5307. Seismological studies of these He core WDs may prove especially fruitful, as their luminosity is related (via stable hydrogen burning) to the hydrogen envelope mass, which eliminates one model parameter.

  9. Communication: Barium ions and helium nanodroplets: Solvation and desolvation

    SciTech Connect (OSTI)

    Zhang Xiaohang; Drabbels, Marcel [Laboratoire de Chimie Physique Moleculaire, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne (Switzerland)

    2012-08-07T23:59:59.000Z

    The solvation of Ba{sup +} ions created by the photoionization of barium atoms located on the surface of helium nanodroplets has been investigated. The excitation spectra corresponding to the 6p {sup 2}P{sub 1/2} Leftwards-Arrow 6s {sup 2}S{sub 1/2} and 6p {sup 2}P{sub 3/2} Leftwards-Arrow 6s {sup 2}S{sub 1/2} transitions of Ba{sup +} are found to be identical to those recorded in bulk He II [H. J. Reyher, H. Bauer, C. Huber, R. Mayer, A. Schafer, and A. Winnacker, Phys. Lett. A 115, 238 (1986)], indicating that the ions formed at the surface of the helium droplets become fully solvated by the helium. Time-of-flight mass spectra suggest that following the excitation of the solvated Ba{sup +} ions, these are being ejected from the helium droplets either as bare Ba{sup +} ions or as small Ba{sup +}He{sub n} (n < 20) complexes.

  10. Helium halo nuclei from low-momentum interactions

    E-Print Network [OSTI]

    S. Bacca; A. Schwenk; G. Hagen; T. Papenbrock

    2009-05-14T23:59:59.000Z

    We present ground-state energies of helium halo nuclei based on chiral low-momentum interactions, using the hyperspherical-harmonics method for 6He and coupled-cluster theory for 8He, with correct asymptotics for the extended halo structure.

  11. Fiber-Optic-Gyroscope Measurements Close to Rotating Liquid Helium

    E-Print Network [OSTI]

    M. Tajmar; F. Plesescu

    2009-11-05T23:59:59.000Z

    We previously reported anomalous fiber-optic gyroscope signals observed above rotating rings at temperatures close to liquid helium. Our results suggested that the liquid helium itself may be the source of our observed phenomenon. We constructed a new cryostat experiment that allows rotating a large quantity of liquid helium together with a superconducting niobium tube. The facility is built in such a way that our gyroscope can be placed directly in the center of rotation along the axis; however, the cryostat is built around the gyroscope to allow measuring without interference of helium liquid or gas. An anomalous signal was found of similar value compared to our previous measurements with a changed sign. As this measurement was done at a different location (center position) with respect to our old setup (top position), first hints for a possible field distribution of this phenomenon can be made. However, due to lower angular velocities used in this new setup so far, our measurement resolution was close to three times the resolution of our gyroscope and hence our data represent work in progress.

  12. Helium and Iron in X-ray galaxy clusters

    E-Print Network [OSTI]

    Stefano Ettori

    2006-10-16T23:59:59.000Z

    I discuss the role of the sedimentation of helium in galaxy cluster cores on the observed X-ray properties and present a history of the metal accumulation in the ICM, with new calculations with respect to my previous work following the recent evidence of a bi-modal distribution of the delay time in Supernovae Type Ia.

  13. The Electrical Conductivity Of Partly Ionized Helium Plasma

    SciTech Connect (OSTI)

    Sreckovic, Vladimir A.; Ignjatovic, Ljubinko; Mihajlov, A. A. [Institute of Physics, PO Box 57, 11001 Belgrade (Serbia and Montenegro)

    2007-04-23T23:59:59.000Z

    In this paper we analyzed atoms influence on electro conductivity, partially ionized helium plasma, in temperature region 5 000 K - 40 000 K and pressure 0.1 - 10 atm. Electro conductivity was calculated using 'Frost like' formula and Random Phase Approximation method and Semi-Classical (SC) approximation.

  14. TRANSMISSION ELECTRON MICROSCOPY STUDY OF HELIUM BEARING FUSION WELDS

    SciTech Connect (OSTI)

    Tosten, M; Michael Morgan, M

    2008-12-12T23:59:59.000Z

    A transmission electron microscopy (TEM) study was conducted to characterize the helium bubble distributions in tritium-charged-and-aged 304L and 21Cr-6Ni-9Mn stainless steel fusion welds containing approximately 150 appm helium-3. TEM foils were prepared from C-shaped fracture toughness test specimens containing {delta} ferrite levels ranging from 4 to 33 volume percent. The weld microstructures in the low ferrite welds consisted mostly of austenite and discontinuous, skeletal {delta} ferrite. In welds with higher levels of {delta} ferrite, the ferrite was more continuous and, in some areas of the 33 volume percent sample, was the matrix/majority phase. The helium bubble microstructures observed were similar in all samples. Bubbles were found in the austenite but not in the {delta} ferrite. In the austenite, bubbles had nucleated homogeneously in the grain interiors and heterogeneously on dislocations. Bubbles were not found on any austenite/austenite grain boundaries or at the austenite/{delta} ferrite interphase interfaces. Bubbles were not observed in the {delta} ferrite because of the combined effects of the low solubility and rapid diffusion of tritium through the {delta} ferrite which limited the amount of helium present to form visible bubbles.

  15. ccsd00004040, Polarized Helium to Image the Lung

    E-Print Network [OSTI]

    ccsd­00004040, version 1 ­ 24 Jan 2005 Polarized Helium to Image the Lung Mich#18;ele Leduc the Lung) are reported. State of the art optical pumping techniques for polarising 3 He gas are described limited by gas di#11;usion. Di#11;usion imaging appears as a robust method of lung diagnosis. A discussion

  16. A New Wide Range Equation of State for Helium-4

    E-Print Network [OSTI]

    Ortiz Vega, Diego O

    2013-08-01T23:59:59.000Z

    A multiparametric and fundamental equation of state is presented for the fluid thermodynamic properties of helium. The equation is valid for temperatures from the ?- line (~2.17 K) to 1500 K and for pressures up to 2000 MPa. The formulation can...

  17. Baseline Concept Description of a Small Modular High Temperature Reactor

    SciTech Connect (OSTI)

    Hans Gougar

    2014-05-01T23:59:59.000Z

    The objective of this report is to provide a description of generic small modular high temperature reactors (herein denoted as an smHTR), summarize their distinguishing attributes, and lay out the research and development (R&D) required for commercialization. The generic concepts rely heavily on the modular high temperature gas-cooled reactor designs developed in the 1980s which were never built but for which pre-licensing or certification activities were conducted. The concept matured more recently under the Next Generation Nuclear Plant (NGNP) project, specifically in the areas of fuel and material qualification, methods development, and licensing. As all vendor-specific designs proposed under NGNP were all both ‘small’ or medium-sized and ‘modular’ by International Atomic Energy Agency (IAEA) and Department of Energy (DOE) standards, the technical attributes, challenges, and R&D needs identified, addressed, and documented under NGNP are valid and appropriate in the context of Small Modular Reactor (SMR) applications. Although the term High Temperature Reactor (HTR) is commonly used to denote graphite-moderated, thermal spectrum reactors with coolant temperatures in excess of 650oC at the core outlet, in this report the historical term High Temperature Gas-Cooled Reactor (HTGR) will be used to distinguish the gas-cooled technology described herein from its liquid salt-cooled cousin. Moreover, in this report it is to be understood that the outlet temperature of the helium in an HTGR has an upper limit of 950 degrees C which corresponds to the temperature to which certain alloys are currently being qualified under DOE’s ARC program. Although similar to the HTGR in just about every respect, the Very High Temperature Reactor (VHTR) may have an outlet temperature in excess of 950 degrees C and is therefore farther from commercialization because of the challenges posed to materials exposed to these temperatures. The VHTR is the focus of R&D under the Generation IV program and its specific R&D needs will be included in this report when appropriate for comparison. The distinguishing features of the HTGR are the refractory (TRISO) coated particle fuel, the low-power density, graphite-moderated core, and the high outlet temperature of the inert helium coolant. The low power density and fuel form effectively eliminate the possibility of core melt, even upon a complete loss of coolant pressure and flow. The graphite, which constitutes the bulk of the core volume and mass, provides a large thermal buffer that absorbs fission heat such that thermal transients occur over a timespan of hours or even days. As chemically-inert helium is already a gas, there is no coolant temperature or void feedback on the neutronics and no phase change or corrosion product that could degrade heat transfer. Furthermore, the particle coatings and interstitial graphite retain fission products such that the source terms at the plant boundary remain well below actionable levels under all anticipated nominal and off-normal operating conditions. These attributes enable the reactor to supply process heat to a collocated industrial plant with negligible risk of contamination and minimal dynamic coupling of the facilities (Figure 1). The exceptional retentive properties of coated particle fuel in a graphite matrix were first demonstrated in the DRAGON reactor, a European research facility that began operation in 1964.

  18. Assessment of HTGR Helium Compressor Analysis Tool Based on Newton-Raphson Numerical Application to Through-flow Analysis

    SciTech Connect (OSTI)

    Ji Hwan Kim; Hyeun Min Kim; Hee Cheon NO [Korea Advanced Institute of Science and Technology, 335 Gwahangno - 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

    2006-07-01T23:59:59.000Z

    This study describes the development of a computer program for analyzing the off-design performance of axial flow helium compressors, which is one of the major concerns for the power conversion system of a high temperature gas-cooled reactor (HTGR). The compressor performance has been predicted by the aerodynamic analysis of meridional flow with allowances for losses. The governing equations have been derived from Euler turbomachine equation and the streamline curvature method, and then they have been merged into linearized equations based on the Newton-Raphson numerical method. The effect of viscosity is considered by empirical correlations to introduce entropy rises caused by primary loss sources. Use of the method has been illustrated by applying it to a 20-stage helium compressor of the GTHTR300 plant. As a result, the flow throughout the stages of the compressor has been predicted and the compressor characteristics have been also investigated according to the design specification. The program results show much better stability and good convergence with respect to other through-flow methods, and good agreement with the compressor performance map provided by JAEA. (authors)

  19. Brookhaven Graphite Research Reactor Workshop

    Broader source: Energy.gov [DOE]

    The Brookhaven Graphite Research Reactor (BGRR) was the first reactor built in the U.S. for peacetime atomic research following World War II.  Construction began in 1947 and the reactor started...

  20. Probing helium interfaces with light scattering : from fluid mechanics to statistical physics

    E-Print Network [OSTI]

    Pierre-Etienne Wolf; Fabien Bonnet; Sylvain Perraud; Laurent Puech; Bernard Rousset; Pierre Thibault

    2008-07-10T23:59:59.000Z

    We have investigated the formation of helium droplets in two physical situations. In the first one, droplets are atomised from superfluid or normal liquid by a fast helium vapour flow. In the second, droplets of normal liquid are formed inside porous glasses during the process of helium condensation. The context, aims, and results of these experiments are reviewed, with focus on the specificity of light scattering by helium. In particular, we discuss how, for different reasons, the closeness to unity of the index of refraction of helium allows in both cases to minimise the problem of multiple scattering and obtain results which it would not be possible to get using other fluids.

  1. REACTOR OPERATIONS AND CONTROL

    E-Print Network [OSTI]

    Pázsit, Imre

    REACTOR OPERATIONS AND CONTROL KEYWORDS: core calculations, neural networks, control rod elevation of a control rod, or a group of control rods, is an important parameter from the viewpoint of reactor control DETERMINATION OF PWR CONTROL ROD POSITION BY CORE PHYSICS AND NEURAL NETWORK METHODS NINOS S. GARIS* and IMRE

  2. Cold Vacuum Drying (CVD) Facility General Service Helium System Design Description

    SciTech Connect (OSTI)

    SHAPLEY, B.J.

    2000-04-20T23:59:59.000Z

    The purpose of this System Design Description (SDD) is to describe the characteristics of the Cold Vacuum Drying (CVD) Facility general service helium system. The general service helium system is a general service facility process support system, but does include safety-class structures, systems and components (SSCs) providing protection to the offsite public. The general service helium system also performs safety-significant functions that provide protection to onsite workers. The general helium system essential function is to provide helium (He) to support process functions during all phases of facility operations. General service helium is used to purge the cask and the MCO in order to maintain their internal atmospheres below hydrogen flammability concentrations. The general service helium system also supplies helium to purge the process water conditioning (PWC) lines and components and the vacuum purge system (VPS) vacuum pump. The general service helium system, if available following an Safety Class Instrument and Control System (SCIC) Isolation and Purge (IS0 and PURGE) Trip, can provide an alternate general service helium system source to supply the Safety-Class Helium (SCHe) System.

  3. Reed Reactor Facility. Final report

    SciTech Connect (OSTI)

    Frantz, S.G.

    1994-12-31T23:59:59.000Z

    This report discusses the operation and maintenance of the Reed Reactor Facility. The Reed reactor is mostly used for education and train purposes.

  4. Reactor & Nuclear Systems Publications | ORNL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Science Home | Science & Discovery | Nuclear Science | Publications and Reports | Reactor and Nuclear Systems Publications SHARE Reactor and Nuclear Systems Publications The...

  5. On the Criticality Safety of Transuranic Sodium Fast Reactor Fuel Transport Casks

    SciTech Connect (OSTI)

    Samuel Bays; Ayodeji Alajo

    2010-05-01T23:59:59.000Z

    This work addresses the neutronic performance and criticality safety issues of transport casks for fuel pertaining to low conversion ratio sodium cooled fast reactors, conventionally known as Advanced Burner Reactors. The criticality of a one, three, seven and 19-assembly cask capacity is presented. Both dry “helium” and flooded “water” filled casks are considered. No credit for fuel burnup or fission products was assumed. As many as possible of the conservatisms used in licensing light water reactor universal transport casks were incorporated into this SFR cask criticality design and analysis. It was found that at 7-assemblies or more, adding moderator to the SFR cask increases criticality margin. Also, removal of MAs from the fuel increases criticality margin of dry casks and takes a slight amount of margin away for wet casks. Assuming credit for borated fuel tube liners, this design analysis suggests that as many as 19 assemblies can be loaded in a cask if limited purely by criticality safety. If no credit for boron is assumed, the cask could possibly hold seven assemblies if low conversion ratio fast reactor grade fuel and not breeder reactor grade fuel is assumed. The analysis showed that there is a need for new cask designs for fast reactors spent fuel transportation. There is a potential of modifying existing transportation cask design as the starting point for fast reactor spent fuel transportation.

  6. Comparative analysis of compact heat exchangers for application as the intermediate heat exchanger for advanced nuclear reactors

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bartel, N.; Chen, M.; Utgikar, V. P.; Sun, X.; Kim, I. H.; Christensen, R.; Sabharwall, P.

    2015-07-01T23:59:59.000Z

    A comparative evaluation of alternative compact heat exchanger designs for use as the intermediate heat exchanger in advanced nuclear reactor systems is presented in this article. Candidate heat exchangers investigated included the Printed circuit heat exchanger (PCHE) and offset strip-fin heat exchanger (OSFHE). Both these heat exchangers offer high surface area to volume ratio (a measure of compactness [m2/m3]), high thermal effectiveness, and overall low pressure drop. Helium–helium heat exchanger designs for different heat exchanger types were developed for a 600 MW thermal advanced nuclear reactor. The wavy channel PCHE with a 15° pitch angle was found to offer optimummore »combination of heat transfer coefficient, compactness and pressure drop as compared to other alternatives. The principles of the comparative analysis presented here will be useful for heat exchanger evaluations in other applications as well.« less

  7. Helium transport in enhanced confinement regimes on the TEXTOR and DIII-D tokamaks

    SciTech Connect (OSTI)

    Hillis, D.L.; Hogan, J.T.; Wade, M.R.; Klepper, C.C.; Mioduszewski, P.K. (Oak Ridge National Lab., TN (United States)); Finken, K.H.; Baek, W.Y.; Dippel, K.H.; Euringer, H.; Pospieszcyk, A.; Reiter, D.; Rusbuldt, D.; Wolf, G.H. (Association Euratom-Kernforschungsanlage Juelich GmbH (Germany)); West, W.P.; Burrell, K.H.; Gohil, P.; Groebner, R.; Seraydarian, R.A. (General Atomics, San Diego, CA (United States))

    1992-04-01T23:59:59.000Z

    Comparisons of helium (He) transport and exhaust in L-mode and in an enhanced confinement regime (H-mode), which is induced by a polarizing electrode, have been made for the TEXTOR tokamak. The results show an increased tendency for He accumulation when bulk plasma energy and particle confinement are improved during the polarization induced H-mode. Since these results imply that a high He pumping efficiency may be necessary for H-mode burning plasmas, we have begun exploring He transport in a divertor H-mode, similar to that proposed for International Thermonuclear Experimental Reactor (ITER). A collaborative program has been initiated to measure He transport and scaling on DIII-D during L-mode, H-mode, and ELMing H-mode plasma conditions. To simulate the presence of He ash in DIII-D, a 25 ms He puff is injected into a DIII-D plasma resulting in a He concentration of {approx}5%. The time dependence of the He{sup 2+} density profiles in the plasma core is measured by charge-exchange recombination spectroscopy at 11 radial locations.

  8. Methane coupling by membrane reactor. First quarterly report, 1997

    SciTech Connect (OSTI)

    Ma, Yi Hua

    1997-05-01T23:59:59.000Z

    The Mn-W-Na/SiO{sub 2} catalyst was studied by running the methane coupling reactions at different methane to oxygen ratios, temperatures and dilution gas flow rates. For methane to oxygen ratios less than 3, the C{sub 2} yield was almost the same; and C{sub 2} yield began to decrease as the methane to oxygen ratio was further increased. The optimal temperature observed was around 800{degrees}C, where the C{sub 2} yield reached a maximum value. Increasing the dilution gas (helium) flow rate resulted in higher C{sub 2} selectivity; however, after a certain dilution gas flow rate the C{sub 2} yield began to decrease due to a decrease in methane conversion as a result of the reduced contact time. The stability study of the catalyst showed that, after five successive run cycles, the C{sub 2} yield obtained decreased from 24% to 19% at 780 {degrees}C, and methane, oxygen and helium flow rates of 12.2, 4.1, and 44. 3 mm/min, respectively. XRD analysis showed that, after the reaction, the XRD peaks of the cristabolite and Na{sub 2}WO{sub 4} phases in the catalyst became smaller than those in the fresh catalyst, and that at least one new, unidentified phase was observed. Mn-W-Na/SiO{sub 2} catalyst was used as the methane oxidative coupling catalyst in a porous membrane reactor and its performance was compared with a packed reactor operated at similar conditions. Although the membrane reactor showed lower methane conversion at the same reaction conditions, it gave higher C{sub 2} selectivity and C{sub 2} yield at similar methane conversions.

  9. Nuclear reactor control column

    SciTech Connect (OSTI)

    Bachovchin, D.M.

    1982-08-10T23:59:59.000Z

    The nuclear reactor control column comprises a column disposed within the nuclear reactor core having a variable cross-section hollow channel and containing balls whose vertical location is determined by the flow of the reactor coolant through the column. The control column is divided into three basic sections wherein each of the sections has a different cross-sectional area. The uppermost section of the control column has the greatest crosssectional area, the intermediate section of the control column has the smallest cross-sectional area, and the lowermost section of the control column has the intermediate cross-sectional area. In this manner, the area of the uppermost section can be established such that when the reactor coolant is flowing under normal conditions therethrough, the absorber balls will be lifted and suspended in a fluidized bed manner in the upper section. However, when the reactor coolant flow falls below a predetermined value, the absorber balls will fall through the intermediate section and into the lowermost section, thereby reducing the reactivity of the reactor core and shutting down the reactor.

  10. Reactor Safety Research Programs

    SciTech Connect (OSTI)

    Edler, S. K.

    1981-07-01T23:59:59.000Z

    This document summarizes the work performed by Pacific Northwest Laboratory (PNL) from January 1 through March 31, 1981, for the Division of Reactor Safety Research within the U.S. Nuclear Regulatory Commission (NRC). Evaluations of nondestructive examination (NDE) techniques and instrumentation are reported; areas of investigation include demonstrating the feasibility of determining the strength of structural graphite, evaluating the feasibility of detecting and analyzing flaw growth in reactor pressure boundary systems, examining NDE reliability and probabilistic fracture mechanics, and assessing the integrity of pressurized water reactor (PWR) steam generator tubes where service-induced degradation has been indicated. Experimental data and analytical models are being provided to aid in decision-making regarding pipeto- pipe impacts following postulated breaks in high-energy fluid system piping. Core thermal models are being developed to provide better digital codes to compute the behavior of full-scale reactor systems under postulated accident conditions. Fuel assemblies and analytical support are being provided for experimental programs at other facilities. These programs include loss-ofcoolant accident (LOCA) simulation tests at the NRU reactor, Chalk River, Canada; fuel rod deformation, severe fuel damage, and postaccident coolability tests for the ESSOR reactor Super Sara Test Program, Ispra, Italy; the instrumented fuel assembly irradiation program at Halden, Norway; and experimental programs at the Power Burst Facility, Idaho National Engineering Laboratory (INEL). These programs will provide data for computer modeling of reactor system and fuel performance during various abnormal operating conditions.

  11. Nuclear reactor control column

    DOE Patents [OSTI]

    Bachovchin, Dennis M. (Plum Borough, PA)

    1982-01-01T23:59:59.000Z

    The nuclear reactor control column comprises a column disposed within the nuclear reactor core having a variable cross-section hollow channel and containing balls whose vertical location is determined by the flow of the reactor coolant through the column. The control column is divided into three basic sections wherein each of the sections has a different cross-sectional area. The uppermost section of the control column has the greatest cross-sectional area, the intermediate section of the control column has the smallest cross-sectional area, and the lowermost section of the control column has the intermediate cross-sectional area. In this manner, the area of the uppermost section can be established such that when the reactor coolant is flowing under normal conditions therethrough, the absorber balls will be lifted and suspended in a fluidized bed manner in the upper section. However, when the reactor coolant flow falls below a predetermined value, the absorber balls will fall through the intermediate section and into the lowermost section, thereby reducing the reactivity of the reactor core and shutting down the reactor.

  12. A Preliminary and Simplified Closed Brayton Cycle Modeling for a Space Reactor Application

    SciTech Connect (OSTI)

    Guimaraes, Lamartine Nogueira Frutuoso; Camillo, Giannino Ponchio [Institute for Advanced Studies, Rodovia dos Tamoios, km 5.5, Putim, 12228-001, Sao Jose dos Campos, SP (Brazil)

    2008-01-21T23:59:59.000Z

    The Nuclear Energy Division (ENU) of the Institute for Advanced Studies (IEAv) has started a preliminary design study for a Closed Brayton Cycle Loop (CBCL) aimed at a space reactor application. The main objectives of the study are: 1) to establish a starting concept for the CBCL components specifications, and 2) to build a demonstrative simulator of CBCL. This preliminary design study is developing the CBCL around the NOELLE 60290 turbo machine. The actual nuclear reactor study is being conducted independently. Because of that, a conventional heat source is being used for the CBCL, in this preliminary design phase. This paper describes the steady state simulator of the CBCL operating with NOELLE 60290 turbo machine. In principle, several gases are being considered as working fluid, as for instance: air, helium, nitrogen, CO{sub 2} and gas mixtures such as helium and xenon. However, for this first application pure helium will be used as working fluid. Simplified models of heat and mass transfer were developed to simulate thermal components. Future efforts will focus on implementing a graphical interface to display the thermal process variables in steady state and to keep track of the modifications being implemented at the NOELLE 60290 turbo machine in order to build the CBCL.

  13. Design of a Simplified Closed Brayton Cycle for a Space Reactor Application

    SciTech Connect (OSTI)

    Guimaraes, Lamartine N. F. [Institute for Advanced Studies-IEAv, Rodovia dos Tamoios, km 5.5, Putim, 12228-001 Sao Jose dos Campos, SP (Brazil); Faculdade de Tecnologia Sao Francisco Jacarei, SP, Brazil 55-12-3947-5474 (Brazil); Camillo, Giannino Ponchio [Institute for Advanced Studies-IEAv, Rodovia dos Tamoios, km 5.5, Putim, 12228-001 Sao Jose dos Campos, SP (Brazil); Placco, Guilherme Moreira [Faculdade de Tecnologia Sao Francisco Jacarei, SP, Brazil 55-12-3947-5474 (Brazil)

    2009-03-16T23:59:59.000Z

    The Nuclear Energy Division (ENU) of the Institute for Advanced Studies (IEAv) has started a preliminary design study for a Closed Brayton Cycle Loop (CBCL) aimed at a space reactor application. The main objectives of the study are: 1) to establish a starting concept for the CBCL components specifications, and 2) to build a demonstrative simulator of CBCL. This preliminary design study is been developed around the NOELLE 60290 turbo machine. The actual nuclear reactor study is being conducted independently. Because of that, a conventional heat source is being used for the CBCL, in this preliminary design phase. This paper describes details of the CBCL mechanical design and the steady state simulator of the CBCL operating with NOELLE 60290 turbo machine. In principle, several gases are being considered as working fluid, as for instance: air, helium, nitrogen, CO2 and gas mixtures such as helium and xenon. However, for this first application pure helium will be used as working fluid. Simplified models of heat and mass transfer were developed to simulate thermal components. A new graphical interface was developed for the simulator to display the thermal process variables in steady state and to keep track of the modifications being implemented at the NOELLE 60290 turbo machine in order to build the CBCL. A set of new results are being produced. These new results help to establish the hot and cold source geometry allowing for price estimating costs for building the actual device. These fresh new results will be presented and discussed.

  14. Fast Breeder Reactor studies

    SciTech Connect (OSTI)

    Till, C.E.; Chang, Y.I.; Kittel, J.H.; Fauske, H.K.; Lineberry, M.J.; Stevenson, M.G.; Amundson, P.I.; Dance, K.D.

    1980-07-01T23:59:59.000Z

    This report is a compilation of Fast Breeder Reactor (FBR) resource documents prepared to provide the technical basis for the US contribution to the International Nuclear Fuel Cycle Evaluation. The eight separate parts deal with the alternative fast breeder reactor fuel cycles in terms of energy demand, resource base, technical potential and current status, safety, proliferation resistance, deployment, and nuclear safeguards. An Annex compares the cost of decommissioning light-water and fast breeder reactors. Separate abstracts are included for each of the parts.

  15. Spherical torus fusion reactor

    DOE Patents [OSTI]

    Martin Peng, Y.K.M.

    1985-10-03T23:59:59.000Z

    The object of this invention is to provide a compact torus fusion reactor with dramatic simplification of plasma confinement design. Another object of this invention is to provide a compact torus fusion reactor with low magnetic field and small aspect ratio stable plasma confinement. In accordance with the principles of this invention there is provided a compact toroidal-type plasma confinement fusion reactor in which only the indispensable components inboard of a tokamak type of plasma confinement region, mainly a current conducting medium which carries electrical current for producing a toroidal magnet confinement field about the toroidal plasma region, are retained.

  16. Nuclear reactor reflector

    DOE Patents [OSTI]

    Hopkins, Ronald J. (Pensacola, FL); Land, John T. (Pensacola, FL); Misvel, Michael C. (Pensacola, FL)

    1994-01-01T23:59:59.000Z

    A nuclear reactor reflector is disclosed that comprises a stack of reflector blocks with vertical water flow passages to cool the reflector. The interface between blocks is opposite support points for reactor fuel rods. Water flows between the reflector and the reactor barrel from passages in a bottom block. The top block contains a flange to limit this flow and the flange has a slot to receive an alignment pin that is welded to the barrel. The pin is held in the slot by two removable shims. Alignment bars extend the length of the stack in slots machined in each block when the stack is assembled.

  17. Nuclear reactor reflector

    DOE Patents [OSTI]

    Hopkins, R.J.; Land, J.T.; Misvel, M.C.

    1994-06-07T23:59:59.000Z

    A nuclear reactor reflector is disclosed that comprises a stack of reflector blocks with vertical water flow passages to cool the reflector. The interface between blocks is opposite support points for reactor fuel rods. Water flows between the reflector and the reactor barrel from passages in a bottom block. The top block contains a flange to limit this flow and the flange has a slot to receive an alignment pin that is welded to the barrel. The pin is held in the slot by two removable shims. Alignment bars extend the length of the stack in slots machined in each block when the stack is assembled. 12 figs.

  18. Microfluidic electrochemical reactors

    DOE Patents [OSTI]

    Nuzzo, Ralph G. (Champaign, IL); Mitrovski, Svetlana M. (Urbana, IL)

    2011-03-22T23:59:59.000Z

    A microfluidic electrochemical reactor includes an electrode and one or more microfluidic channels on the electrode, where the microfluidic channels are covered with a membrane containing a gas permeable polymer. The distance between the electrode and the membrane is less than 500 micrometers. The microfluidic electrochemical reactor can provide for increased reaction rates in electrochemical reactions using a gaseous reactant, as compared to conventional electrochemical cells. Microfluidic electrochemical reactors can be incorporated into devices for applications such as fuel cells, electrochemical analysis, microfluidic actuation, pH gradient formation.

  19. DESIGN AND LAYOUT CONCEPTS FOR COMPACT, FACTORY-PRODUCED, TRANSPORTABLE, GENERATION IV REACTOR SYSTEMS

    SciTech Connect (OSTI)

    Mynatt Fred R.; Townsend, L.W.; Williamson, Martin; Williams, Wesley; Miller, Laurence W.; Khan, M. Khurram; McConn, Joe; Kadak, Andrew C.; Berte, Marc V.; Sawhney, Rapinder; Fife, Jacob; Sedler, Todd L.; Conway, Larry E.; Felde, Dave K.

    2003-11-12T23:59:59.000Z

    The purpose of this research project is to develop compact (100 to 400 MWe) Generation IV nuclear power plant design and layout concepts that maximize the benefits of factory-based fabrication and optimal packaging, transportation and siting. The reactor concepts selected were compact designs under development in the 2000 to 2001 period. This interdisciplinary project was comprised of three university-led nuclear engineering teams identified by reactor coolant type (water, gas, and liquid metal) and a fourth Industrial Engineering team. The reactors included a Modular Pebble Bed helium-cooled concept being developed at MIT, the IRIS water-cooled concept being developed by a team led by Westinghouse Electric Company, and a Lead-Bismuth-cooled concept developed by UT. In addition to the design and layout concepts this report includes a section on heat exchanger manufacturing simulations and a section on construction and cost impacts of proposed modular designs.

  20. Effect of Helium Accumulation on the Spent Fuel Microstructure

    SciTech Connect (OSTI)

    Ferry, Cecile [Department of Physico-chemistry, Commissariat a l'Energie Atomique, CEA-Saclay, Gif-sur-Yvette, 91191 (France); Piron, Jean-Paul [Commisariat a l'Energie Atomique, CEA - Cadarache, Saint-Paul Lez Durance, 13108 (France); Stout, Ray [Rho Beta Sigma Affaires, Livermore, CA, CA 94550 (United States)

    2007-07-01T23:59:59.000Z

    In a nuclear spent fuel repository, the aqueous rapid release of radio-activity from exposed spent fuel surfaces will depend on the pellet microstructure at the arrival time of water into the disposal container. Research performed on spent fuel evolution in a closed system has shown that the evolution of microstructure under disposal conditions should be governed by the cumulated {alpha}-decay damage and the subsequent helium behavior. The evolution of fission gas bubble characteristics under repository conditions has to be assessed. In UO{sub 2} fuels with a burnup of 47.5 GWd/t, the pressure in fission gas bubbles, including the pressure increase from {alpha}-decay helium atoms, is not expected to reach the critical bubble pressure that will cause failure, thus micro-cracking in UO{sub 2} spent fuel grains is not expected. (authors)

  1. Source localization of brain activity using helium-free interferometer

    SciTech Connect (OSTI)

    Dammers, Jürgen, E-mail: J.Dammers@fz-juelich.de; Chocholacs, Harald; Eich, Eberhard; Boers, Frank [Institute of Neuroscience and Medicine (INM-4), Forschungszentrum Jülich, Jülich (Germany); Faley, Michael; Dunin-Borkowski, Rafal E. [Peter Grünberg Institute (PGI-5), Forschungszentrum Jülich, Jülich (Germany); Jon Shah, N. [Institute of Neuroscience and Medicine (INM-4), Forschungszentrum Jülich, Jülich (Germany); Department of Neurology, RWTH Aachen University, Aachen (Germany); Jülich Aachen Research Alliance (JARA)—Translational Brain Medicine, Jülich (Germany)

    2014-05-26T23:59:59.000Z

    To detect extremely small magnetic fields generated by the human brain, currently all commercial magnetoencephalography (MEG) systems are equipped with low-temperature (low-T{sub c}) superconducting quantum interference device (SQUID) sensors that use liquid helium for cooling. The limited and increasingly expensive supply of helium, which has seen dramatic price increases recently, has become a real problem for such systems and the situation shows no signs of abating. MEG research in the long run is now endangered. In this study, we report a MEG source localization utilizing a single, highly sensitive SQUID cooled with liquid nitrogen only. Our findings confirm that localization of neuromagnetic activity is indeed possible using high-T{sub c} SQUIDs. We believe that our findings secure the future of this exquisitely sensitive technique and have major implications for brain research and the developments of cost-effective multi-channel, high-T{sub c} SQUID-based MEG systems.

  2. The Helium Cryogenic System for the ATLAS Experiment

    E-Print Network [OSTI]

    Delruelle, N; Passardi, Giorgio; ten Kate, H H J

    2000-01-01T23:59:59.000Z

    The magnetic configuration of the ATLAS detector is generated by an inner superconducting solenoid and three air-core toroids (the barrel and two end-caps), each of them made of eight superconducting coils. Two separated helium refrigerators will be used to allow cool-down from ambient temperature and steady-state operation at 4.5 K of all the magnets having a total cold mass of about 600 tons. In comparison with the preliminary design, the helium distribution scheme and interface with the magnet sub-systems are simplified, resulting in a considerable improvement of the operational easiness and the overall reliability of the system at some expense of the operational flexibility. The paper presents the cryogenic layout and the basic principles for magnets cool-down, steady state operation and thermal recovery after a fast energy dump.

  3. Electron bubbles in liquid helium: infrared-absorption spectrum

    E-Print Network [OSTI]

    Víctor Grau; Manuel Barranco; Ricardo Mayol; Martí Pi

    2006-01-20T23:59:59.000Z

    Within Density Functional Theory, we have calculated the energy of the transitions from the ground state to the first two excited states in the electron bubbles in liquid helium at pressures from zero to about the solidification pressure. For $^4$He at low temperatures, our results are in very good agreement with infrared absorption experiments. Above a temperature of $\\sim 2$ K, we overestimate the energy of the $1s-1p$ transition. We attribute this to the break down of the Franck-Condon principle due to the presence of helium vapor inside the bubble. Our results indicate that the $1s-2p$ transition energies are sensitive not only to the size of the electron bubble, but also to its surface thickness. We also present results for the infrared transitions in the case of liquid $^3$He, for which we lack of experimental data.

  4. DETERMINING THE INITIAL HELIUM ABUNDANCE OF THE SUN

    SciTech Connect (OSTI)

    Serenelli, Aldo M. [Max Planck Institute for Astrophysics, Karl Schwarzschild Str. 1, Garching D-85471 (Germany); Basu, Sarbani, E-mail: aldos@mpa-garching.mpg.d [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States)

    2010-08-10T23:59:59.000Z

    We determine the dependence of the initial helium abundance and the present-day helium abundance in the convective envelope of solar models (Y {sub ini} and Y {sub surf}, respectively) on the parameters that are used to construct the models. We do so by using reference standard solar models (SSMs) to compute the power-law coefficients of the dependence of Y {sub ini} and Y {sub surf} on the input parameters. We use these dependencies to determine the correlation between Y {sub ini} and Y {sub surf} and use this correlation to eliminate uncertainties in Y {sub ini} from all solar model input parameters except the microscopic diffusion rate. We find an expression for Y {sub ini} that depends only on Y {sub surf} and the diffusion rate. By adopting the helioseismic determination of solar surface helium abundance, Y {sup surf} {sub sun} = 0.2485 {+-} 0.0035, and an uncertainty of 20% for the diffusion rate, we find that the initial solar helium abundance, Y {sup ini} {sub sun}, is 0.278 {+-} 0.006 independently of the reference SSMs (and particularly on the adopted solar abundances) used in the derivation of the correlation between Y {sub ini} and Y {sub surf}. When non-SSMs with extra mixing are used, then we derive Y {sup ini} {sub sun} = 0.273 {+-} 0.006. In both cases, the derived Y {sup ini} {sub sun} value is higher than that directly derived from solar model calibrations when the low-metallicity solar abundances (e.g., by Asplund et al.) are adopted in the models.

  5. Shock compression of liquid helium to 56 GPa (560 kbar)

    SciTech Connect (OSTI)

    Nellis, W.J.; Holmes, N.C.; Mitchell, A.C.; Trainor, R.J.; Governo, G.K.; Ross, M.; Young, D.A.

    1984-09-24T23:59:59.000Z

    The first shock-compression experiments on liquid helium are reported. With a two-stage light-gas gun, liquid He at 4.3 K and 1 atm was shocked to 16 GPa and 12 000 K and double shocked to 56 GPa and 21 000 K. Liquid perturbation theory has been used to determine an effective interatomic potential from which the equation of state of He can be obtained over a wide range of densities and temperatures.

  6. Lung Function Measurement with Multiple-Breath-Helium Washout System

    E-Print Network [OSTI]

    Wang, Jau-Yi; Owers-Bradley, John; Mellor, Chris

    2011-01-01T23:59:59.000Z

    Multiple-breath-washout (MBW) measurements are regarded as a sensitive technique which can reflect the ventilation inhomogeneity of respiratory airways. Typically nitrogen is used as the tracer gas and is washed out by pure oxygen in multi-breath-nitrogen (MBNW) washout tests. In this work, instead of using nitrogen, helium is used as the tracer gas and a multiple-helium-breath-washout (MBHW) system has been developed for the lung function study. A commercial quartz tuning fork with a resonance frequency of 32768 Hz has been used for detecting the change of the respiratory gas density. The resonance frequency of the tuning fork decreases linearly with increasing density of the surrounding gas. Knowing the CO2 concentration from the infrared carbon dioxide detector, the helium concentration can be determined. Results from 12 volunteers (3 mild asthmatics, 2 smokers, 1 with asthma history, 1 with COPD history, 5 normal) have shown that mild asthmatics have higher ventilation inhomogeneity in either conducting o...

  7. UCN production by multiphonon processes in superfluid Helium under pressure

    E-Print Network [OSTI]

    P. Schmidt-Wellenburg; K. H. Andersen; O. Zimmer

    2009-01-29T23:59:59.000Z

    Cold neutrons are converted to ultra-cold neutrons (UCN) by the excitation of a single phonon or multiphonons in superfluid helium. The dynamic scattering function S(q, omega) of the superfluid helium strongly depends on pressure, leading to a pressure- dependent differential UCN production rate. A phenomenological expression for the multiphonon part of the scattering function s(lambda) describing UCN production has been derived from inelastic neutron scattering data. When combined with the production rate from single phonon processes this allows us to calculate the UCN production for any incident neutron flux. For calculations of the UCN production from single phonon processes we propose to use the values for S*(SVP) = 0.118(8) and S*(20 bar) = 0.066(6). As an example we will calculate the expected UCN production rate at the cold neutron beam for fundamental physics PF1b at the Institut Laue Langevin. We conclude that UCN production in superfluid helium under pressure is not attractive.

  8. Hypothetical Reactor Accident Study

    E-Print Network [OSTI]

    POPULATIONS; IODINE 131; MELTDOWN; METEOROLOGY; NUCLEAR POWER PLANTS; P CODES; PWR TYPE REACTORS; RADIATION in a Typical BWR and in a typical PWR. Comparison with WASH-1400 by C F . Højerup 202 APPENDIX 3. Calculation

  9. P Reactor Grouting

    SciTech Connect (OSTI)

    None

    2010-01-01T23:59:59.000Z

    Filling the P Reactor with grout. This seals the radioactive material and reduces the environmental footprint left from the Cold War. Project sponsored by the Recovery Act at the Savannah River Site.

  10. Nuclear reactor control

    SciTech Connect (OSTI)

    Ingham, R.V.

    1980-01-01T23:59:59.000Z

    A liquid metal cooled fast breeder nuclear reactor has power setback means for use in an emergency. On initiation of a trip-signal a control rod is injected into the core in two stages, firstly, by free fall to effect an immediate power-set back to a safe level and, secondly, by controlled insertion. Total shut-down of the reactor under all emergencies is avoided. 4 claims.

  11. Polymerization reactor control

    SciTech Connect (OSTI)

    Ray, W.H.

    1985-01-01T23:59:59.000Z

    The principal difficulties in achieving good control of polymerization reactors are related to inadequate on-line measurement, a lack of understanding of the dynamics of the process, the highly sensitive and nonlinear behavior of these reactors, and the lack of well-developed techniques for the control of nonlinear processes. Some illustrations of these problems and a discussion of potential techniques for overcoming some of these difficulties is provided.

  12. Molten metal reactors

    DOE Patents [OSTI]

    Bingham, Dennis N; Klingler, Kerry M; Turner, Terry D; Wilding, Bruce M

    2013-11-05T23:59:59.000Z

    A molten metal reactor for converting a carbon material and steam into a gas comprising hydrogen, carbon monoxide, and carbon dioxide is disclosed. The reactor includes an interior crucible having a portion contained within an exterior crucible. The interior crucible includes an inlet and an outlet; the outlet leads to the exterior crucible and may comprise a diffuser. The exterior crucible may contain a molten alkaline metal compound. Contained between the exterior crucible and the interior crucible is at least one baffle.

  13. Reactor- Nuclear Science Center 

    E-Print Network [OSTI]

    Unknown

    2011-08-17T23:59:59.000Z

    A COMPARISON OF NUCLEAR REACTOR CONTROL ROOM DISPLAY PANELS A Thesis by FRANCES RENAE BOWERS Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1988... Major Subject: Industrial Engineering A COMPARISON OF NUCLEAR REACTOR CONTROL ROOM DISPLAY PANELS A Thesis by FRANCES RENAE BOWERS Approved as to style and content by: Rod er . oppa (Cha' of 'ttee) R. Quinn Brackett (Member) rome . Co gleton...

  14. Helium-Based Soundwave Chiller: Trillium: A Helium-Based Sonic Chiller- Tons of Freezing with 0 GWP Refrigerants

    SciTech Connect (OSTI)

    None

    2010-09-01T23:59:59.000Z

    BEETIT Project: Penn State is designing a freezer that substitutes the use of sound waves and environmentally benign refrigerant for synthetic refrigerants found in conventional freezers. Called a thermoacoustic chiller, the technology is based on the fact that the pressure oscillations in a sound wave result in temperature changes. Areas of higher pressure raise temperatures and areas of low pressure decrease temperatures. By carefully arranging a series of heat exchangers in a sound field, the chiller is able to isolate the hot and cold regions of the sound waves. Penn State’s chiller uses helium gas to replace synthetic refrigerants. Because helium does not burn, explode or combine with other chemicals, it is an environmentally-friendly alternative to other polluting refrigerants. Penn State is working to apply this technology on a large scale.

  15. Power Burst Facility (PBF) Reactor Reactor Decommissioning

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible forPortsmouth/Paducah Project Office PressPostdoctoraldecadal7Powder DropperReactor

  16. Reactor Safety Research Programs

    SciTech Connect (OSTI)

    Dotson, CW

    1980-08-01T23:59:59.000Z

    This document summarizes the work performed by Pacific Northwest laboratory from October 1 through December 31, 1979, for the Division of Reactor Safety Research within the Nuclear Regulatory Commission. Evaluation of nondestructive examination (NDE) techniques and instrumentation are reported; areas of investigation include demonstrating the feasibilty of determining structural graphite strength, evaluating the feasibilty of detecting and analyzing flaw growth in reactor pressure boundary systems, examining NDE reliability and probabilistic fracture mechanics, and assessing the remaining integrity of pressurized water reactor steam generator tubes where service-induced degradation has been indicated. Test assemblies and analytical support are being provided for experimental programs at other facilities. These programs include the loss-of-coolant accident simulation tests at the NRU reactor, Chalk River, Canada; the fuel rod deformation and post-accident coolability tests for the ESSOR Test Reactor Program, lspra, Italy; the blowdown and reflood tests in the test facility at Cadarache, France; the instrumented fuel assembly irradiation program at Halden, Norway; and the experimental programs at the Power Burst Facility, Idaho National Engineering Laboratory. These programs will provide data for computer modeling of reactor system and fuel performance during various abnormal operating conditions.

  17. F Reactor Inspection

    SciTech Connect (OSTI)

    Grindstaff, Keith; Hathaway, Boyd; Wilson, Mike

    2014-10-29T23:59:59.000Z

    Workers from Mission Support Alliance, LLC., removed the welds around the steel door of the F Reactor before stepping inside the reactor to complete its periodic inspection. This is the first time the Department of Energy (DOE) has had the reactor open since 2008. The F Reactor is one of nine reactors along the Columbia River at the Department's Hanford Site in southeastern Washington State, where environmental cleanup has been ongoing since 1989. As part of the Tri-Party Agreement, the Department completes surveillance and maintenance activities of cocooned reactors periodically to evaluate the structural integrity of the safe storage enclosure and to ensure confinement of any remaining hazardous materials. "This entry marks a transition of sorts because the Hanford Long-Term Stewardship Program, for the first time, was responsible for conducting the entry and surveillance and maintenance activities," said Keith Grindstaff, Energy Department Long-Term Stewardship Program Manager. "As the River Corridor cleanup work is completed and transitioned to long-term stewardship, our program will manage any on-going requirements."

  18. F Reactor Inspection

    ScienceCinema (OSTI)

    Grindstaff, Keith; Hathaway, Boyd; Wilson, Mike

    2014-11-24T23:59:59.000Z

    Workers from Mission Support Alliance, LLC., removed the welds around the steel door of the F Reactor before stepping inside the reactor to complete its periodic inspection. This is the first time the Department of Energy (DOE) has had the reactor open since 2008. The F Reactor is one of nine reactors along the Columbia River at the Department's Hanford Site in southeastern Washington State, where environmental cleanup has been ongoing since 1989. As part of the Tri-Party Agreement, the Department completes surveillance and maintenance activities of cocooned reactors periodically to evaluate the structural integrity of the safe storage enclosure and to ensure confinement of any remaining hazardous materials. "This entry marks a transition of sorts because the Hanford Long-Term Stewardship Program, for the first time, was responsible for conducting the entry and surveillance and maintenance activities," said Keith Grindstaff, Energy Department Long-Term Stewardship Program Manager. "As the River Corridor cleanup work is completed and transitioned to long-term stewardship, our program will manage any on-going requirements."

  19. US ITER (International Thermonuclear Experimental Reactor) shield and blanket design activities

    SciTech Connect (OSTI)

    Baker, C.C.

    1988-08-01T23:59:59.000Z

    This paper summarizes nuclear-related work in support of the US effort for the International Thermonuclear Experimental Reactor (ITER) Study. Primary tasks carried out during the past year include design improvements of the inboard shield developed for the TIBER concept, scoping studies of a variety of tritium breeding blanket options, development of necessary design guidelines and evaluation criteria for the blanket options, further safety considerations related to nuclear components, and issues regarding structural materials for an ITER device. The blanket concepts considered are the aqueous/Li salt solution, a water-cooled, solid breeder blanket, a helium-cooled, solid-breeder blanket, a blanket cooled by helium containing lithium-bearing particulates, and a blanket concept based on breeding tritium from He/sup 3/. 1 ref., 2 tabs.

  20. Production of carbon monoxide-free hydrogen and helium from a high-purity source

    DOE Patents [OSTI]

    Golden, Timothy Christopher (Allentown, PA); Farris, Thomas Stephen (Bethlehem, PA)

    2008-11-18T23:59:59.000Z

    The invention provides vacuum swing adsorption processes that produce an essentially carbon monoxide-free hydrogen or helium gas stream from, respectively, a high-purity (e.g., pipeline grade) hydrogen or helium gas stream using one or two adsorber beds. By using physical adsorbents with high heats of nitrogen adsorption, intermediate heats of carbon monoxide adsorption, and low heats of hydrogen and helium adsorption, and by using vacuum purging and high feed stream pressures (e.g., pressures of as high as around 1,000 bar), pipeline grade hydrogen or helium can purified to produce essentially carbon monoxide -free hydrogen and helium, or carbon monoxide, nitrogen, and methane-free hydrogen and helium.

  1. Status of Preconceptual Design of the Advanced High-Temperature Reactor (AHTR)

    SciTech Connect (OSTI)

    Ingersoll, D.T.

    2004-07-29T23:59:59.000Z

    A new reactor plant concept is presented that combines the benefits of ceramic-coated, high-temperature particle fuel with those of clean, high-temperature, low-pressure molten salt coolant. The Advanced High-Temperature Reactor (AHTR) concept is a collaboration of Oak Ridge National Laboratory, Sandia National Laboratories, and the University of California at Berkeley. The purpose of the concept is to provide an advanced design capable of satisfying the top-level functional requirements of the U.S. Department of Energy Next Generation Nuclear Plant (NGNP), while also providing a technology base that is sufficiently robust to allow future development paths to higher temperatures and larger outputs with highly competitive economics. This report summarizes the status of the AHTR preconceptual design. It captures the results from an intense effort over a period of 3 months to (1) screen and examine potential feasibility concerns with the concept; (2) refine the conceptual design of major systems; and (3) identify research, development, and technology requirements to fully mature the AHTR design. Several analyses were performed and are presented to quantify the AHTR performance expectations and to assist in the selection of several design parameters. The AHTR, like other NGNP reactor concepts, uses coated particle fuel in a graphite matrix. But unlike the other NGNP concepts, the AHTR uses molten salt rather than helium as the primary system coolant. The considerable previous experience with molten salts in nuclear environments is discussed, and the status of high-temperature materials is reviewed. The large thermal inertia of the system, the excellent heat transfer and fission product retention characteristics of molten salt, and the low-pressure operation of the primary system provide significant safety attributes for the AHTR. Compared with helium coolant, a molten salt cooled reactor will have significantly lower fuel temperatures (150-200-C lower) for the equivalent temperature of heat delivered to either the power conversion system or a hydrogen production plant. Using a comparative cost analysis, the construction costs per unit output are projected to be 50-55% of the costs for modular gas-cooled or sodium-cooled reactor systems. This is primarily a consequence of substantially larger power output and higher conversion efficiency for the AHTR. The AHTR has a number of unique technical challenges in meeting the NGNP requirements; however, it appears to offer advantages over high-temperature helium-cooled reactors and provides an alternative development path to achieve the NGNP requirements. Primary challenges include optimizing the core design for improved response to transients, designing an internal blanket to thermally protect the reactor vessel, and engineering solutions to high-temperature refueling and maintenance.

  2. Thermal hydraulic performance testing of printed circuit heat exchangers in a high-temperature helium test facility

    SciTech Connect (OSTI)

    Sai K. Mylavarapu; Xiaodong Sun; Richard E. Glosup; Richard N. Christensen; Michael W. Patterson

    2014-04-01T23:59:59.000Z

    In high-temperature gas-cooled reactors, such as a very high temperature reactor (VHTR), an intermediate heat exchanger (IHX) is required to efficiently transfer the core thermal output to a secondary fluid for electricity generation with an indirect power cycle and/or process heat applications. Currently, there is no proven high-temperature (750–800 °C or higher) compact heat exchanger technology for high-temperature reactor design concepts. In this study, printed circuit heat exchanger (PCHE), a potential IHX concept for high-temperature applications, has been investigated for their heat transfer and pressure drop characteristics under high operating temperatures and pressures. Two PCHEs, each having 10 hot and 10 cold plates with 12 channels (semicircular cross-section) in each plate are fabricated using Alloy 617 plates and tested for their performance in a high-temperature helium test facility (HTHF). The PCHE inlet temperature and pressure were varied from 85 to 390 °C/1.0–2.7 MPa for the cold side and 208–790 °C/1.0–2.7 MPa for the hot side, respectively, while the mass flow rate of helium was varied from 15 to 49 kg/h. This range of mass flow rates corresponds to PCHE channel Reynolds numbers of 950 to 4100 for the cold side and 900 to 3900 for the hot side (corresponding to the laminar and laminar-to-turbulent transition flow regimes). The obtained experimental data have been analyzed for the pressure drop and heat transfer characteristics of the heat transfer surface of the PCHEs and compared with the available models and correlations in the literature. In addition, a numerical treatment of hydrodynamically developing and hydrodynamically fully-developed laminar flow through a semicircular duct is presented. Relations developed for determining the hydrodynamic entrance length in a semicircular duct and the friction factor (or pressure drop) in the hydrodynamic entry length region for laminar flow through a semicircular duct are given. Various hydrodynamic entrance region parameters, such as incremental pressure drop number, apparent Fanning friction factor, and hydrodynamic entrance length in a semicircular duct have been numerically estimated.

  3. Prognostics Health Management for Advanced Small Modular Reactor Passive Components

    SciTech Connect (OSTI)

    Meyer, Ryan M.; Ramuhalli, Pradeep; Coble, Jamie B.; Mitchell, Mark R.; Wootan, David W.; Hirt, Evelyn H.; Berglin, Eric J.; Bond, Leonard J.; Henager, Charles H.

    2013-10-18T23:59:59.000Z

    In the United States, sustainable nuclear power to promote energy security is a key national energy priority. Advanced small modular reactors (AdvSMR), which are based on modularization of advanced reactor concepts using non-light-water reactor (LWR) coolants such as liquid metal, helium, or liquid salt may provide a longer-term alternative to more conventional LWR-based concepts. The economics of AdvSMRs will be impacted by the reduced economy-of-scale savings when compared to traditional LWRs and the controllable day-to-day costs of AdvSMRs are expected to be dominated by operations and maintenance costs. Therefore, achieving the full benefits of AdvSMR deployment requires a new paradigm for plant design and management. In this context, prognostic health management of passive components in AdvSMRs can play a key role in enabling the economic deployment of AdvSMRs. In this paper, the background of AdvSMRs is discussed from which requirements for PHM systems are derived. The particle filter technique is proposed as a prognostics framework for AdvSMR passive components and the suitability of the particle filter technique is illustrated by using it to forecast thermal creep degradation using a physics-of-failure model and based on a combination of types of measurements conceived for passive AdvSMR components.

  4. Gas tagging and cover gas combination for nuclear reactor

    DOE Patents [OSTI]

    Gross, Kenny C. (Lemont, IL); Laug, Matthew T. (Idaho Falls, ID)

    1985-01-01T23:59:59.000Z

    The invention discloses the use of stable isotopes of neon and argon, that are grouped in preselected different ratios one to the other and are then sealed as tags in different cladded nuclear fuel elements to be used in a liquid metal fast breeder reactor. Failure of the cladding of any fuel element allows fission gases generated in the reaction and these tag isotopes to escape and to combine with the cover gas held in the reactor over the fuel elements. The isotopes specifically are Ne.sup.20, Ne.sup.21 and Ne.sup.22 of neon and Ar.sup.36, Ar.sup.38 and Ar.sup.40 of argon, and the cover gas is helium. Serially connected cryogenically operated charcoal beds are used to clean the cover gas and to separate out the tags. The first or cover gas cleanup bed is held between approximately 0.degree. and -25.degree. C. operable to remove the fission gases from the cover gas and tags and the second or tag recovery system bed is held between approximately -170.degree. and -185.degree. C. operable to isolate the tags from the cover gas. Spectrometric analysis further is used to identify the specific tags that are recovered, and thus the specific leaking fuel element. By cataloging the fuel element tags to the location of the fuel elements in the reactor, the location of the leaking fuel element can then be specifically determined.

  5. Reactor Safety Planning for Prometheus Project, for Naval Reactors Information

    SciTech Connect (OSTI)

    P. Delmolino

    2005-05-06T23:59:59.000Z

    The purpose of this letter is to submit to Naval Reactors the initial plan for the Prometheus project Reactor Safety work. The Prometheus project is currently developing plans for cold physics experiments and reactor prototype tests. These tests and facilities may require safety analysis and siting support. In addition to the ground facilities, the flight reactor units will require unique analyses to evaluate the risk to the public from normal operations and credible accident conditions. This letter outlines major safety documents that will be submitted with estimated deliverable dates. Included in this planning is the reactor servicing documentation and shipping analysis that will be submitted to Naval Reactors.

  6. Zero Power Reactor simulation | Argonne National Laboratory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Zero Power Reactor simulation Share Description Ever wanted to see a nuclear reactor core in action? Here's a detailed simulation of the Zero Power Reactor experiment, run by...

  7. Energy-related applications of helium: a revision of the ERDA-13 data base

    SciTech Connect (OSTI)

    Hammel, E.F.; Krupka, M.C.

    1980-08-01T23:59:59.000Z

    A re-examination, revision, and re-evaluation of the data base contained within the 1975 document, ERDA-13, The Energy-Related Applications of Helium, were completed and results are presented in this report. New technical and resource data, current legislative proposals, updated supply-and-demand relationships, latest legal developments, programmatic changes affectng the future demand for helium, socio-economic aspects, and the effects of the latest energy-consumption projections were considered and are discussed. In contrast to ERDA-13, however, explicit recommendations with respect to the formulation of Federal helium policy, as it pertains to the energy-related applications of helium, are not given.

  8. Interim Report on the Optimization and Feasibility Studies for the Neutron Detection without Helium-3 Project

    SciTech Connect (OSTI)

    Ely, James H.

    2012-03-19T23:59:59.000Z

    This report provides the status and results of the first year's effort in modeling and simulation to investigate alternatives to helium-3 for neutron detection in safeguards applications.

  9. Bubble microstructure evolution and helium behavior in He{sup +} implanted Ni-base alloys

    SciTech Connect (OSTI)

    Kalin, B.A.; Chernov, I.I.; Kalashnikov, A.N.; Solovyev, B.G. [Moscow State Engineering Physics Inst., Moscow (Russian Federation). Dept. of Physical Problems of Materials Science

    1996-12-31T23:59:59.000Z

    Behavior of ion-implanted helium in Ni as a function of alloying element concentration (Al or Ti) and irradiation conditions (at 20 or 750 C) have been investigated by means of thermal desorption spectrometry (TDS) and transmission electron microscopy (TEM). Substitution elements in solid solution were demonstrated to have substantial influence on the evolution of implanted helium, shifting the TDS spectrum peaks to higher temperature region and increasing the quantity of helium remaining in the samples after long-time postirradiation annealing. TEM investigations showed that in the case of postirradiation annealing, helium bubbles are formed earlier in quenched alloys than in those annealed.

  10. Cold Vacuum Drying (CVD) Facility General Service Helium System Design Description

    SciTech Connect (OSTI)

    FARWICK, C.C.

    1999-07-06T23:59:59.000Z

    This document describes the Cold Vacuum Drying Facility general service helium system (GSHe). The GSHe is a general service facility process support system, but does include safety-class systems, structures and components providing protection to the offsite public. The GSHe also performs safety-significant functions that provide protection to onsite workers. The GSHe essential function is to provide helium to support process functions during all phases of facility operations. GSHe helium is used to purge the cask and the MCO in order to maintain their internal atmospheres below hydrogen flammability concentrations. The GSHe also supplies helium to purge the PWC lines and components and the VPS vacuum pump.

  11. Ultra high vacuum pumping system and high sensitivity helium leak detector

    DOE Patents [OSTI]

    Myneni, Ganapati Rao (Yorktown, VA)

    1997-01-01T23:59:59.000Z

    An improved helium leak detection method and apparatus are disclosed which increase the leak detection sensitivity to 10.sup.-13 atm cc s.sup.-1. The leak detection sensitivity is improved over conventional leak detectors by completely eliminating the use of o-rings, equipping the system with oil-free pumping systems, and by introducing measured flows of nitrogen at the entrances of both the turbo pump and backing pump to keep the system free of helium background. The addition of dry nitrogen flows to the system reduces backstreaming of atmospheric helium through the pumping system as a result of the limited compression ratios of the pumps for helium.

  12. Ultra high vacuum pumping system and high sensitivity helium leak detector

    DOE Patents [OSTI]

    Myneni, G.R.

    1997-12-30T23:59:59.000Z

    An improved helium leak detection method and apparatus are disclosed which increase the leak detection sensitivity to 10{sup {minus}13} atm cc/s. The leak detection sensitivity is improved over conventional leak detectors by completely eliminating the use of o-rings, equipping the system with oil-free pumping systems, and by introducing measured flows of nitrogen at the entrances of both the turbo pump and backing pump to keep the system free of helium background. The addition of dry nitrogen flows to the system reduces back streaming of atmospheric helium through the pumping system as a result of the limited compression ratios of the pumps for helium. 2 figs.

  13. The Hottest Horizontal-Branch Stars in omega Centauri - Late Hot Flasher vs. Helium Enrichment

    E-Print Network [OSTI]

    S. Moehler; S. Dreizler; T. Lanz; G. Bono; A. V. Sweigart; A. Calamida; M. Monelli; M. Nonino

    2007-09-18T23:59:59.000Z

    UV observations of some massive globular clusters uncovered a significant population of very hot stars below the hot end of the horizontal branch (HB), the so-called blue hook stars. This feature might be explained either as results of the late hot flasher scenario where stars experience the helium flash while on the white dwarf cooling curve or by the progeny of the helium-enriched sub-population recently postulated to exist in some clusters. Moderately high resolution spectra of stars at the hot end of the blue HB in omega Cen were analysed for atmospheric parameters and abundances using LTE and Non-LTE model atmospheres. In the temperature range 30,000K to 50,000K we find that 35% of our stars are helium-poor (log(n_He/n_H) -0.4). We also find carbon enrichment in step with helium enrichment, with a maximum carbon enrichment of 3% by mass. At least 14% of the hottest HB stars in omega Cen show helium abundances well above the highest predictions from the helium enrichment scenario (Y = 0.42 corresponding to log(n_He/n_H) ~ -0.74). In addition, the most helium-rich stars show strong carbon enrichment as predicted by the late hot flasher scenario. We conclude that the helium-rich HB stars in omega Cen cannot be explained solely by the helium-enrichment scenario invoked to explain the blue main sequence. (Abridged)

  14. Facility Configuration Study of the High Temperature Gas-Cooled Reactor Component Test Facility

    SciTech Connect (OSTI)

    S. L. Austad; L. E. Guillen; D. S. Ferguson; B. L. Blakely; D. M. Pace; D. Lopez; J. D. Zolynski; B. L. Cowley; V. J. Balls; E.A. Harvego, P.E.; C.W. McKnight, P.E.; R.S. Stewart; B.D. Christensen

    2008-04-01T23:59:59.000Z

    A test facility, referred to as the High Temperature Gas-Cooled Reactor Component Test Facility or CTF, will be sited at Idaho National Laboratory for the purposes of supporting development of high temperature gas thermal-hydraulic technologies (helium, helium-Nitrogen, CO2, etc.) as applied in heat transport and heat transfer applications in High Temperature Gas-Cooled Reactors. Such applications include, but are not limited to: primary coolant; secondary coolant; intermediate, secondary, and tertiary heat transfer; and demonstration of processes requiring high temperatures such as hydrogen production. The facility will initially support completion of the Next Generation Nuclear Plant. It will secondarily be open for use by the full range of suppliers, end-users, facilitators, government laboratories, and others in the domestic and international community supporting the development and application of High Temperature Gas-Cooled Reactor technology. This pre-conceptual facility configuration study, which forms the basis for a cost estimate to support CTF scoping and planning, accomplishes the following objectives: • Identifies pre-conceptual design requirements • Develops test loop equipment schematics and layout • Identifies space allocations for each of the facility functions, as required • Develops a pre-conceptual site layout including transportation, parking and support structures, and railway systems • Identifies pre-conceptual utility and support system needs • Establishes pre-conceptual electrical one-line drawings and schedule for development of power needs.

  15. Methanation assembly using multiple reactors

    DOE Patents [OSTI]

    Jahnke, Fred C.; Parab, Sanjay C.

    2007-07-24T23:59:59.000Z

    A methanation assembly for use with a water supply and a gas supply containing gas to be methanated in which a reactor assembly has a plurality of methanation reactors each for methanating gas input to the assembly and a gas delivery and cooling assembly adapted to deliver gas from the gas supply to each of said methanation reactors and to combine water from the water supply with the output of each methanation reactor being conveyed to a next methanation reactor and carry the mixture to such next methanation reactor.

  16. A TEN MEGAWATT BOILING HETEROGENEOUS PACKAGE POWER REACTOR. Reactor...

    Office of Scientific and Technical Information (OSTI)

    A reactor and associated power plant designed to produce 1.05 Mwh and 3.535 Mwh of steam for heating purposes are described. The total thermal output of the reactor is 10 Mwh....

  17. Energy spectra of finite temperature superfluid helium-4 turbulence

    SciTech Connect (OSTI)

    Kivotides, Demosthenes [Department of Aeronautics, Imperial College London, London SW7 2AZ (United Kingdom)

    2014-10-15T23:59:59.000Z

    A mesoscopic model of finite temperature superfluid helium-4 based on coupled Langevin-Navier-Stokes dynamics is proposed. Drawing upon scaling arguments and available numerical results, a numerical method for designing well resolved, mesoscopic calculations of finite temperature superfluid turbulence is developed. The application of model and numerical method to the problem of fully developed turbulence decay in helium II, indicates that the spectral structure of normal-fluid and superfluid turbulence is significantly more complex than that of turbulence in simple-fluids. Analysis based on a forced flow of helium-4 at 1.3 K, where viscous dissipation in the normal-fluid is compensated by the Lundgren force, indicate three scaling regimes in the normal-fluid, that include the inertial, low wavenumber, Kolmogorov k{sup ?5/3} regime, a sub-turbulence, low Reynolds number, fluctuating k{sup ?2.2} regime, and an intermediate, viscous k{sup ?6} range that connects the two. The k{sup ?2.2} regime is due to normal-fluid forcing by superfluid vortices at high wavenumbers. There are also three scaling regimes in the superfluid, that include a k{sup ?3} range that corresponds to the growth of superfluid vortex instabilities due to mutual-friction action, and an adjacent, low wavenumber, k{sup ?5/3} regime that emerges during the termination of this growth, as superfluid vortices agglomerate between intense normal-fluid vorticity regions, and weakly polarized bundles are formed. There is also evidence of a high wavenumber k{sup ?1} range that corresponds to the probing of individual-vortex velocity fields. The Kelvin waves cascade (the main dynamical effect in zero temperature superfluids) appears to be damped at the intervortex space scale.

  18. Reactor for exothermic reactions

    DOE Patents [OSTI]

    Smith, Jr., Lawrence A. (Bellaire, TX); Hearn, Dennis (Houston, TX); Jones, Jr., Edward M. (Friendswood, TX)

    1993-01-01T23:59:59.000Z

    A liquid phase process for oligomerization of C.sub.4 and C.sub.5 isoolefins or the etherification thereof with C.sub.1 to C.sub.6 alcohols wherein the reactants are contacted in a reactor with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of 120.degree. to 300.degree. F. Wherein the improvement is the operation of the reactor at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized. By operating at the boiling point and allowing a portion of the reaction mixture to vaporize, the exothermic heat of reaction is dissipated by the formation of more boil up and the temperature in the reactor is controlled.

  19. Thermionic Reactor Design Studies

    SciTech Connect (OSTI)

    Schock, Alfred

    1994-08-01T23:59:59.000Z

    Paper presented at the 29th IECEC in Monterey, CA in August 1994. The present paper describes some of the author's conceptual designs and their rationale, and the special analytical techniques developed to analyze their (thermionic reactor) performance. The basic designs, first published in 1963, are based on single-cell converters, either double-ended diodes extending over the full height of the reactor core or single-ended diodes extending over half the core height. In that respect they are similar to the thermionic fuel elements employed in the Topaz-2 reactor subsequently developed in the Soviet Union, copies of which were recently imported by the U.S. As in the Topaz-2 case, electrically heated steady-state performance tests of the converters are possible before fueling.

  20. Reactor for exothermic reactions

    DOE Patents [OSTI]

    Smith, L.A. Jr.; Hearn, D.; Jones, E.M. Jr.

    1993-03-02T23:59:59.000Z

    A liquid phase process is described for oligomerization of C[sub 4] and C[sub 5] isoolefins or the etherification thereof with C[sub 1] to C[sub 6] alcohols wherein the reactants are contacted in a reactor with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of 120 to 300 F. Wherein the improvement is the operation of the reactor at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized. By operating at the boiling point and allowing a portion of the reaction mixture to vaporize, the exothermic heat of reaction is dissipated by the formation of more boil up and the temperature in the reactor is controlled.

  1. Nuclear reactor safety device

    DOE Patents [OSTI]

    Hutter, Ernest (Wilmette, IL)

    1986-01-01T23:59:59.000Z

    A safety device is disclosed for use in a nuclear reactor for axially repositioning a control rod with respect to the reactor core in the event of an upward thermal excursion. Such safety device comprises a laminated helical ribbon configured as a tube-like helical coil having contiguous helical turns with slidably abutting edges. The helical coil is disclosed as a portion of a drive member connected axially to the control rod. The laminated ribbon is formed of outer and inner laminae. The material of the outer lamina has a greater thermal coefficient of expansion than the material of the inner lamina. In the event of an upward thermal excursion, the laminated helical coil curls inwardly to a smaller diameter. Such inward curling causes the total length of the helical coil to increase by a substantial increment, so that the control rod is axially repositioned by a corresponding amount to reduce the power output of the reactor.

  2. Fusion reactor control

    SciTech Connect (OSTI)

    Plummer, D.A.

    1995-12-31T23:59:59.000Z

    The plasma kinetic temperature and density changes, each per an injected fuel density rate increment, control the energy supplied by a thermonuclear fusion reactor in a power production cycle. This could include simultaneously coupled control objectives for plasma current, horizontal and vertical position, shape and burn control. The minimum number of measurements required, use of indirect (not plasma parameters) system measurements, and distributed control procedures for burn control are to be verifiable in a time dependent systems code. The International Thermonuclear Experimental Reactor (ITER) has the need to feedback control both the fusion output power and the driven plasma current, while avoiding damage to diverter plates. The system engineering of fusion reactors must be performed to assure their development expeditiously and effectively by considering reliability, availability, maintainability, environmental impact, health and safety, and cost.

  3. Heat dissipating nuclear reactor

    DOE Patents [OSTI]

    Hunsbedt, Anstein (Los Gatos, CA); Lazarus, Jonathan D. (Sunnyvale, CA)

    1987-01-01T23:59:59.000Z

    Disclosed is a nuclear reactor containment adapted to retain and cool core debris in the unlikely event of a core meltdown and subsequent breach in the reactor vessel. The reactor vessel is seated in a cavity which has a thick metal sidewall that is integral with a thick metal basemat at the bottom of the cavity. The basemat extends beyond the perimeter of the cavity sidewall. Underneath the basemat is a porous bed with water pipes and steam pipes running into it. Water is introduced into the bed and converted into steam which is vented to the atmosphere. A plurality of metal pilings in the form of H-beams extends from the metal base plate downwardly and outwardly into the earth.

  4. Heat dissipating nuclear reactor

    DOE Patents [OSTI]

    Hunsbedt, A.; Lazarus, J.D.

    1985-11-21T23:59:59.000Z

    Disclosed is a nuclear reactor containment adapted to retain and cool core debris in the unlikely event of a core meltdown and subsequent breach in the reactor vessel. The reactor vessel is seated in a cavity which has a thick metal sidewall that is integral with a thick metal basemat at the bottom of the cavity. The basemat extends beyond the perimeter of the cavity sidewall. Underneath the basemat is a porous bed with water pipes and steam pipes running into it. Water is introduced into the bed and converted into steam which is vented to the atmosphere. A plurality of metal pilings in the form of H-beams extend from the metal base plate downwardly and outwardly into the earth.

  5. Cathode fall measurement in a dielectric barrier discharge in helium

    SciTech Connect (OSTI)

    Hao, Yanpeng; Zheng, Bin; Liu, Yaoge [School of Electric Power, South China University of Technology, Guangzhou 510640 (China)] [School of Electric Power, South China University of Technology, Guangzhou 510640 (China)

    2013-11-15T23:59:59.000Z

    A method based on the “zero-length voltage” extrapolation is proposed to measure cathode fall in a dielectric barrier discharge. Starting, stable, and discharge-maintaining voltages were measured to obtain the extrapolation zero-length voltage. Under our experimental conditions, the “zero-length voltage” gave a cathode fall of about 185 V. Based on the known thickness of the cathode fall region, the spatial distribution of the electric field strength in dielectric barrier discharge in atmospheric helium is determined. The strong cathode fall with a maximum field value of approximately 9.25 kV/cm was typical for the glow mode of the discharge.

  6. A tentative replica theory of glassy Helium 4

    E-Print Network [OSTI]

    Giulio Biroli; Francesco Zamponi

    2012-05-18T23:59:59.000Z

    We develop a quantum replica method for interacting particle systems and use it to estimate the location of the glass transition line in Helium 4. Although we do not fully succeed in taking into account all quantum effects, we make a thorough semiclassical analysis. We confirm previous suggestions that quantum fluctuations promote the formation of the glass and give a quantitative estimate of this effect at high density. Finally, we discuss the difficulties that are met when one tries to extend the calculation to the region of low densities and low temperatures, where quantum effects are strong and the semiclassical expansion breaks down.

  7. Double ionization of Helium from a phase space perspective

    E-Print Network [OSTI]

    Elie Assémat; Shai Machnes; David Tannor

    2015-02-18T23:59:59.000Z

    The aim of this paper is two-fold. First, we present a phase space perspective on long range double ionization in a one dimensional model of helium. The dynamics is simulated with the periodic von Neumann (PvB) method, an exact quantum method based on a lattice of phase space Gaussians. Second, we benchmark the method by comparing to the Multiconfiguration Time-dependent Hartree method. The PvB approach is found to be faster than the standard MCTDH code for the dynamics calculations and to give better accuracy control.

  8. Interaction effects on dynamical localization in driven helium

    E-Print Network [OSTI]

    Felix Jörder; Klaus Zimmermann; Alberto Rodriguez; Andreas Buchleitner

    2014-08-22T23:59:59.000Z

    Dynamical localization prevents driven atomic systems from fast fragmentation by hampering the excitation process. We present numerical simulations within a collinear model of microwave-driven helium Rydberg atoms and prove that dynamical localization survives the impact of electron-electron interaction, even for doubly excited states in the presence of fast autoionization. We conclude that the effect of electron-electron repulsion on localization can be described by an appropriate rescaling of the atomic level density and of the external field with the strength of the interaction.

  9. Entanglement in helium atom confined in an impenetrable cavity

    E-Print Network [OSTI]

    Przemyslaw Koscik; Jayanta K. Saha

    2015-05-24T23:59:59.000Z

    We explore ground-state entanglement properties of helium atom confined at the center of an impenetrable spherical cavity of varying radius by using explicitly correlated Hylleraas-type basis set. Results for the dependencies of the von Neumann and linear entanglement entropic measures on the cavity radius are discussed in details. Some highly accurate numerical results for the von Neumann and linear entropy are reported for the first time. It is found that the transition to the strong confinement regime is manifested by the entropies as an appearance of the inflection points on their variations.

  10. Avian embryonic development in a helium-oxygen atmosphere

    E-Print Network [OSTI]

    Miller, David Harrison

    1968-01-01T23:59:59.000Z

    -through of the helium-oxygen mixture or com- pressed breathing air, (Figure 1, 2, and 3). Although the chambers were tightly sealed and a slight pressure inside the chamber showed no leaks when tested with a soapy solution, the interior atmosphere (He-02), became... seal without the use of tape. A slight positive pressure wss maintained inside each chamber and a soapy solution or ~gnoo (manufactured by Nuclear Products Co. , Cleveland, Ohio) was used to test for leaks. The chamber with He-02 was flushed...

  11. Thermal analysis for fuel handling system for sodium cooled reactor considering minor actinide-bearing metal fuel.

    SciTech Connect (OSTI)

    Chikazawa, Y.; Grandy, C.; Nuclear Engineering Division

    2009-03-01T23:59:59.000Z

    The Advanced Burner Reactor (ABR) is one of the components of the Global Nuclear Energy Partnership (GNEP) used to close the fuel cycle. ABR is a sodium-cooled fast reactor that is used to consume transuranic elements resulting from the reprocessing of light water reactor spent nuclear fuel. ABR-1000 [1000 MW(thermal)] is a fast reactor concept created at Argonne National Laboratory to be used as a reference concept for various future trade-offs. ABR-1000 meets the GNEP goals although it uses what is considered base sodium fast reactor technology for its systems and components. One of the considerations of any fast reactor plant concept is the ability to perform fuel-handling operations with new and spent fast reactor fuel. The transmutation fuel proposed as the ABR fuel has a very little experience base, and thus, this paper investigates a fuel-handling concept and potential issues of handling fast reactor fuel containing minor actinides. In this study, two thermal analyses supporting a conceptual design study on the ABR-1000 fuel-handling system were carried out. One analysis investigated passive dry spent fuel storage, and the other analysis investigated a fresh fuel shipping cask. Passive dry storage can be made suitable for the ABR-1000 spent fuel storage with sodium-bonded metal fuel. The thermal analysis shows that spent fast reactor fuel with a decay heat of 2 kW or less can be stored passively in a helium atmosphere. The 2-kW value seems to be a reasonable and practical level, and a combination of reasonably-sized in-sodium storage followed by passive dry storage could be a candidate for spent fuel storage for the next-generation sodium-cooled reactor with sodium-bonded metal fuel. Requirements for the shipping casks for minor actinide-bearing fuel with a high decay heat level are also discussed in this paper. The shipping cask for fresh sodium-cooled-reactor fuel should be a dry type to reduce the reaction between residual moisture on fresh fuel and the sodium coolant. The cladding temperature requirement is maintained below the creep temperature limit to avoid any damage before core installation. The thermal analysis shows that a helium gas-filled cask can accommodate ABR-1000 fresh minor actinide-bearing fuel with 700-W decay heat. The above analysis results revealed the overall requirement for minor actinide-bearing metal fuel handling. The information is thought to be helpful in the design of the ABR-1000 and future sodium-cooled-reactor fuel-handling system.

  12. Fast quench reactor method

    DOE Patents [OSTI]

    Detering, Brent A. (Idaho Falls, ID); Donaldson, Alan D. (Idaho Falls, ID); Fincke, James R. (Idaho Falls, ID); Kong, Peter C. (Idaho Falls, ID); Berry, Ray A. (Idaho Falls, ID)

    1999-01-01T23:59:59.000Z

    A fast quench reaction includes a reactor chamber having a high temperature heating means such as a plasma torch at its inlet and a means of rapidly expanding a reactant stream, such as a restrictive convergent-divergent nozzle at its outlet end. Metal halide reactants are injected into the reactor chamber. Reducing gas is added at different stages in the process to form a desired end product and prevent back reactions. The resulting heated gaseous stream is then rapidly cooled by expansion of the gaseous stream.

  13. Fast quench reactor method

    DOE Patents [OSTI]

    Detering, B.A.; Donaldson, A.D.; Fincke, J.R.; Kong, P.C.; Berry, R.A.

    1999-08-10T23:59:59.000Z

    A fast quench reaction includes a reactor chamber having a high temperature heating means such as a plasma torch at its inlet and a means of rapidly expanding a reactant stream, such as a restrictive convergent-divergent nozzle at its outlet end. Metal halide reactants are injected into the reactor chamber. Reducing gas is added at different stages in the process to form a desired end product and prevent back reactions. The resulting heated gaseous stream is then rapidly cooled by expansion of the gaseous stream. 8 figs.

  14. Fusion reactor pumped laser

    DOE Patents [OSTI]

    Jassby, Daniel L. (Princeton, NJ)

    1988-01-01T23:59:59.000Z

    A nuclear pumped laser capable of producing long pulses of very high power laser radiation is provided. A toroidal fusion reactor provides energetic neutrons which are slowed down by a moderator. The moderated neutrons are converted to energetic particles capable of pumping a lasing medium. The lasing medium is housed in an annular cell surrounding the reactor. The cell includes an annular reflecting mirror at the bottom and an annular output window at the top. A neutron reflector is disposed around the cell to reflect escaping neutrons back into the cell. The laser radiation from the annular window is focused onto a beam compactor which generates a single coherent output laser beam.

  15. Reactor Neutrino Experiments

    E-Print Network [OSTI]

    Jun Cao

    2007-12-06T23:59:59.000Z

    Precisely measuring $\\theta_{13}$ is one of the highest priority in neutrino oscillation study. Reactor experiments can cleanly determine $\\theta_{13}$. Past reactor neutrino experiments are reviewed and status of next precision $\\theta_{13}$ experiments are presented. Daya Bay is designed to measure $\\sin^22\\theta_{13}$ to better than 0.01 and Double Chooz and RENO are designed to measure it to 0.02-0.03. All are heading to full operation in 2010. Recent improvements in neutrino moment measurement are also briefed.

  16. Perspectives on reactor safety

    SciTech Connect (OSTI)

    Haskin, F.E. [New Mexico Univ., Albuquerque, NM (United States). Dept. of Chemical and Nuclear Engineering; Camp, A.L. [Sandia National Labs., Albuquerque, NM (United States)

    1994-03-01T23:59:59.000Z

    The US Nuclear Regulatory Commission (NRC) maintains a technical training center at Chattanooga, Tennessee to provide appropriate training to both new and experienced NRC employees. This document describes a one-week course in reactor, safety concepts. The course consists of five modules: (1) historical perspective; (2) accident sequences; (3) accident progression in the reactor vessel; (4) containment characteristics and design bases; and (5) source terms and offsite consequences. The course text is accompanied by slides and videos during the actual presentation of the course.

  17. THE MATERIALS OF FAST BREEDER REACTORS

    E-Print Network [OSTI]

    Olander, Donald R.

    2013-01-01T23:59:59.000Z

    times larger in a fast reactor than in a thermal reactor,structural metals in a fast reactor will be subject to farof fuel ele- ments in fast reactors which are roughly one

  18. Innovative design of uranium startup fast reactors

    E-Print Network [OSTI]

    Fei, Tingzhou

    2012-01-01T23:59:59.000Z

    Sodium Fast Reactors are one of the three candidates of GEN-IV fast reactors. Fast reactors play an important role in saving uranium resources and reducing nuclear wastes. Conventional fast reactors rely on transuranic ...

  19. Reactor operation environmental information document

    SciTech Connect (OSTI)

    Haselow, J.S.; Price, V.; Stephenson, D.E.; Bledsoe, H.W.; Looney, B.B.

    1989-12-01T23:59:59.000Z

    The Savannah River Site (SRS) produces nuclear materials, primarily plutonium and tritium, to meet the requirements of the Department of Defense. These products have been formed in nuclear reactors that were built during 1950--1955 at the SRS. K, L, and P reactors are three of five reactors that have been used in the past to produce the nuclear materials. All three of these reactors discontinued operation in 1988. Currently, intense efforts are being extended to prepare these three reactors for restart in a manner that protects human health and the environment. To document that restarting the reactors will have minimal impacts to human health and the environment, a three-volume Reactor Operations Environmental Impact Document has been prepared. The document focuses on the impacts of restarting the K, L, and P reactors on both the SRS and surrounding areas. This volume discusses the geology, seismology, and subsurface hydrology. 195 refs., 101 figs., 16 tabs.

  20. Power calibrations for TRIGA reactors

    SciTech Connect (OSTI)

    Whittemore, W.L.; Razvi, J.; Shoptaugh, J.R. Jr. [General Atomics, San Diego, CA (United States)

    1988-07-01T23:59:59.000Z

    The purpose of this paper is to establish a framework for the calorimetric power calibration of TRIGA reactors so that reliable results can be obtained with a precision better than {+-} 5%. Careful application of the same procedures has produced power calibration results that have been reproducible to {+-} 1.5%. The procedures are equally applicable to the Mark I, Mark II and Mark III reactors as well as to reactors having much larger reactor tanks and to TRIGA reactors capable of forced cooling up to 3 MW in some cases and 15 MW in another case. In the case of forced cooled TRIGA reactors, the calorimetric power calibration is applicable in the natural convection mode for these reactors using exactly the same procedures as are discussed below for the smaller TRIGA reactors (< 2 MW)

  1. Reactor operation safety information document

    SciTech Connect (OSTI)

    Not Available

    1990-01-01T23:59:59.000Z

    The report contains a reactor facility description which includes K, P, and L reactor sites, structures, operating systems, engineered safety systems, support systems, and process and effluent monitoring systems; an accident analysis section which includes cooling system anomalies, radioactive materials releases, and anticipated transients without scram; a summary of onsite doses from design basis accidents; severe accident analysis (reactor core disruption); a description of operating contractor organization and emergency planning; and a summary of reactor safety evolution. (MB)

  2. Reed Reactor Facility Annual Report

    SciTech Connect (OSTI)

    Frantz, Stephen G.

    2000-09-01T23:59:59.000Z

    This is the report of the operations, experiments, modifications, and other aspects of the Reed Reactor Facility for the year.

  3. Comparison Between Air and Helium for Use as Working Fluids in the Energy-Conversion Cycle of the MPBR

    E-Print Network [OSTI]

    Galen, T. A.

    A comparison between air and helium for use as working fluids in the energy-conversion cycle of the MPBR is presented. To date, helium has been selected in the MPBR indirect-cycle working reference design. Air open- and ...

  4. Hydrogen and helium entrapment in flowing liquid metal plasma-facing surfaces

    E-Print Network [OSTI]

    Harilal, S. S.

    Hydrogen and helium entrapment in flowing liquid metal plasma-facing surfaces Ahmed Hassanein the PFC surface (helium and hydrogen isotopes) while accommodating high heat loads. To study this problem. Hydrogen isotope (DT) particles are likely be trapped in the liquid metal surface (e.g., lithium) due

  5. The Solar Wind Helium Abundance: Variation with Wind Speed and the Solar Cycle

    E-Print Network [OSTI]

    Richardson, John

    The Solar Wind Helium Abundance: Variation with Wind Speed and the Solar Cycle Matthias R. Aellig Alamos National Lab., Los Alamos, NM 87545 Abstract We investigate the helium abundance in the solar wind of 1994 and early 2000 are analyzed. In agreement with similar work for previous solar cycles, we find

  6. The role of helium implantation induced vacancy defect on hardening of tungsten

    SciTech Connect (OSTI)

    Ou, Xin, E-mail: x.ou@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden (Germany); State Key Laboratory of Functional Material for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200250 (China); Anwand, Wolfgang, E-mail: w.anwand@hzdr.de; Kögler, Reinhard, E-mail: r.koegler@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden (Germany); Zhou, Hong-Bo [Department of Physics, Beihang University, Beijing 100191 (China); Richter, Asta, E-mail: asta.richter@th-wildau.de [Technische Hochschule Wildau, Hochschulring1, 15745 Wildau (Germany)

    2014-03-28T23:59:59.000Z

    Vacancy-type defects created by helium implantation in tungsten and their impact on the nano-hardness characteristics were investigated by correlating the results from the positron annihilation spectroscopy and the nano-indentation technique. Helium implantation was performed at room temperature (RT) and at an elevated temperate of 600?°C. Also, the effect of post-annealing of the RT implanted sample was studied. The S parameter characterizing the open volume in the material was found to increase after helium irradiation and is significantly enhanced for the samples thermally treated at 600?°C either by irradiation at high temperature or by post-annealing. Two types of helium-vacancy defects were detected after helium irradiation; small defects with high helium-to-vacancy ratio (low S parameter) for RT irradiation and large defects with low helium-to-vacancy ratio (high S parameter) for thermally treated tungsten. The hardness of the heat treated tungsten coincides with the S parameter, and hence is controlled by the large helium-vacancy defects. The hardness of tungsten irradiated at RT without thermal treatment is dominated by manufacturing related defects such as dislocation loops and impurity clusters and additionally by trapped He atoms from irradiation effects, which enhance hardness. He-stabilized dislocation loops mainly cause the very high hardness values in RT irradiated samples without post-annealing.

  7. THE HELIUM ABUNDANCE IN POLAR CORONAL HOLES AND THE FAST SOLAR WIND

    SciTech Connect (OSTI)

    Byhring, H. S., E-mail: hanne-sigrun.byhring@uit.no [Department of Physics and Technology, University of Tromsoe, No-9037 Tromsoe (Norway)

    2011-09-10T23:59:59.000Z

    I have studied the helium abundance in polar coronal holes and the fast solar wind using a time-dependent numerical model for the hydrogen-helium solar wind that spans the mid-to-upper chromosphere, transition region, corona, and solar wind. The model calculates the particle density, flow velocity, parallel and perpendicular temperature, and heat flux for all particle species simultaneously. The focus is on (1) the coronal/solar wind helium abundance as a function of the total magnetic field expansion and (2) the coronal abundance enhancements resulting from low helium heating rates. It is shown that the magnetic field expansion factor may be important in the determination of the solar wind helium abundance and that this can be understood in terms of gravitational settling in the chromosphere. I find that a total magnetic field expansion factor of about 20 is consistent with the observed helium abundance in the solar wind. Furthermore, it is demonstrated that existing observations, both spectroscopic observations of the corona and in situ observations in the solar wind, are compatible with helium abundance enhancements in the corona. For proton-electron plasma properties in accordance with observations, the coronal helium abundance enhancements occur in the region 1.2-2 R{sub sun}.

  8. Entanglement entropies in the ground states of helium-like atoms

    E-Print Network [OSTI]

    Przemyslaw Koscik; Anna Okopinska

    2014-06-01T23:59:59.000Z

    We examine the entanglement in the ground states of helium and helium-like ions using an original Hylleraas expansion. The von Neumann and linear entropies of the reduced density matrix are accurately computed by performing the Schmidt decomposition of the S singlet spatial wavefunctions. The results presented are more accurate than currently available in published literature.

  9. Modeling hydrogen and helium entrapment in flowing liquid metal surfaces as plasma-facing components in

    E-Print Network [OSTI]

    Harilal, S. S.

    Modeling hydrogen and helium entrapment in flowing liquid metal surfaces as plasma the PFC surface (helium and hydrogen isotopes) while accommodating high heat loads. To study this problem rather than requiring a standard vacuum system. Hydrogen isotope (DT) particles that strike the surface

  10. ccsd-00004040,version1-24Jan2005 Polarized Helium to Image the Lung

    E-Print Network [OSTI]

    ccsd-00004040,version1-24Jan2005 Polarized Helium to Image the Lung Mich`ele Leduc and Pierre Jean Paris1 Abstract The main findings of the european PHIL project (Polarised Helium to Image the Lung diffusion. Diffusion imaging appears as a robust method of lung diagnosis. A discussion of the potential

  11. The Source of the Helium Visible Lines in Eta Carinae

    E-Print Network [OSTI]

    Kashi, A; Kashi, Amit; Soker, Noam

    2007-01-01T23:59:59.000Z

    We assume that the helium-I lines emitted by the massive binary system Eta Carinae are formed in the acceleration zone of the less-massive secondary star. We calculate the Doppler shift of the lines as a function of orbital phase and of several parameters of the binary system. We find that a good fit is obtained if the helium lines are formed in the region where the secondary wind speed is 430 km/sec. The acceptable binary eccentricity is in the range 0.9-0.95, and the inclination angle (the angle between a line perpendicular to the orbital plane and the line of sight) is in the range 40-55 degrees. Lower values of e require higher values of i, and vice versa. The binary system is oriented such that the secondary star is in our direction (closer to us) during periastron passage. The orbital motion can account in part to the Doppler shift of the peak in X-ray emission.

  12. The Source of the Helium Visible Lines in Eta Carinae

    E-Print Network [OSTI]

    Amit Kashi; Noam Soker

    2007-04-13T23:59:59.000Z

    We assume that the helium-I lines emitted by the massive binary system Eta Carinae are formed in the acceleration zone of the less-massive secondary star. We calculate the Doppler shift of the lines as a function of orbital phase and of several parameters of the binary system. We find that a good fit is obtained if the helium lines are formed in the region where the secondary wind speed is 430 km/sec. The acceptable binary eccentricity is in the range 0.9-0.95, and the inclination angle (the angle between a line perpendicular to the orbital plane and the line of sight) is in the range 40-55 degrees. Lower values of e require higher values of i, and vice versa. The binary system is oriented such that the secondary star is in our direction (closer to us) during periastron passage. The orbital motion can account in part to the Doppler shift of the peak in X-ray emission.

  13. Ignition and extinction phenomena in helium micro hollow cathode discharges

    SciTech Connect (OSTI)

    Kulsreshath, M. K.; Schwaederle, L.; Dufour, T.; Lefaucheux, P.; Dussart, R. [GREMI, CNRS/Université d'Orléans (UMR7344), Orléans (France); Sadeghi, N. [LIPhy, CNRS and Universite Joseph Fourier (UMR5588), Grenoble (France); Overzet, L. J. [GREMI, CNRS/Université d'Orléans (UMR7344), Orléans (France); PSAL, UTDallas, Richardson, Texas 75080-3021 (United States)

    2013-12-28T23:59:59.000Z

    Micro hollow cathode discharges (MHCD) were produced using 250??m thick dielectric layer of alumina sandwiched between two nickel electrodes of 8??m thickness. A through cavity at the center of the chip was formed by laser drilling technique. MHCD with a diameter of few hundreds of micrometers allowed us to generate direct current discharges in helium at up to atmospheric pressure. A slowly varying ramped voltage generator was used to study the ignition and the extinction periods of the microdischarges. The analysis was performed by using electrical characterisation of the V-I behaviour and the measurement of He*({sup 3}S{sub 1}) metastable atoms density by tunable diode laser spectroscopy. At the ignition of the microdischarges, 2??s long current peak as high as 24?mA was observed, sometimes followed by low amplitude damped oscillations. At helium pressure above 400?Torr, an oscillatory behaviour of the discharge current was observed just before the extinction of the microdischarges. The same type of instability in the extinction period at high pressure also appeared on the density of He*({sup 3}S{sub 1}) metastable atoms, but delayed by a few ?s relative to the current oscillations. Metastable atoms thus cannot be at the origin of the generation of the observed instabilities.

  14. Gettering of hydrogen and methane from a helium gas mixture

    SciTech Connect (OSTI)

    Cárdenas, Rosa Elia, E-mail: recarde1@uiwtx.edu [Department of Physics, The University of the Incarnate Word, 4301 Broadway, San Antonio, Texas 78209 (United States); Stewart, Kenneth D.; Cowgill, Donald F., E-mail: dfcowgi@sandia.gov [Sandia National Laboratories, Hydrogen and Metallurgical Sciences, 7011 East Avenue, Livermore, California 94550 (United States)

    2014-11-01T23:59:59.000Z

    In this study, the authors developed an approach for accurately quantifying the helium content in a gas mixture also containing hydrogen and methane using commercially available getters. The authors performed a systematic study to examine how both H{sub 2} and CH{sub 4} can be removed simultaneously from the mixture using two SAES St 172{sup ®} getters operating at different temperatures. The remaining He within the gas mixture can then be measured directly using a capacitance manometer. The optimum combination involved operating one getter at 650?°C to decompose the methane, and the second at 110?°C to remove the hydrogen. This approach eliminated the need to reactivate the getters between measurements, thereby enabling multiple measurements to be made within a short time interval, with accuracy better than 1%. The authors anticipate that such an approach will be particularly useful for quantifying the He-3 in mixtures that include tritium, tritiated methane, and helium-3. The presence of tritiated methane, generated by tritium activity, often complicates such measurements.

  15. Development of monitoring system of helium leakage from canister

    SciTech Connect (OSTI)

    Toriu, D. [Kyoto University, CERE, Kyoto, 615-8540 (Japan); Ushijima, S. [Kyoto University, ACCMS, Kyoto, 606-8501 (Japan); Takeda, H. [Central Research Institute of Electric Power Industry - CRIEPI, Abiko 1646, 270-1194 (Japan)

    2013-07-01T23:59:59.000Z

    This paper presents a computational method for the helium leakage from a canister. The governing equations for compressible fluids consist of mass conservation equation in Eulerian description, momentum equations and energy equation. The numerical procedures are divided into three phases, advection, diffusion and acoustic phases, and the equations of compressible fluids are discretized with a finite volume method. Thus, the mass conservation law is sufficiently satisfied in the calculation region. In particular, our computational method enables us to predict the change of the temperature distributions around the canister boundaries by calculating the governing equations for the compressible gas flows, which are leaked out from a slight crack on the canister boundary. In order to confirm the validity of our method, it was applied to the basic problem, 2-dimensional natural convection flows in a rectangular cavity. As a result, it was shown that the naturally convected flows can be reasonably simulated by our method. Furthermore, numerical experiments were conducted for the helium leakage from canister and we derived a close relationship between the inner pressure and the boundary temperature distributions.

  16. Large quantum superpositions of a nanoparticle immersed in superfluid helium

    E-Print Network [OSTI]

    Oleg Lychkovskiy

    2015-04-02T23:59:59.000Z

    Preparing and detecting spatially extended quantum superpositions of a massive object comprises an important fundamental test of quantum theory. State-of-the-art experiments demonstrate quantum interference of nanometer-sized molecules with mass $\\sim 10^4$ amu. A number of experiments have been proposed to push the mass limit several orders of magnitude further. All the experimental setups considered up to date require that the nanoparticle is isolated in a sufficiently high vacuum in order to avoid collisional decoherence. We argue that superfluid helium is a viable alternative to vacuum as a low-decoherence medium. Indeed, for an object moving in a pure superfluid at zero temperature with a velocity less than the critical one decoherence is absent since the object can not create any excitations of the superfluid. In real life impurities and thermal excitations will cause decoherence. We show that it is low enough to permit interference experiments with nanoparticles well beyond the current mass limit. While the robustness of spatial superpositions of an objects surrounded by dense medium is remarkable in its own right, performing interference experiments in superfluid helium can provide some practical advantages compared to conventional schemes, e.g. effective cooling and compensation of gravity by the buoyancy force.

  17. Nuclear Reactors and Technology

    SciTech Connect (OSTI)

    Cason, D.L.; Hicks, S.C. [eds.

    1992-01-01T23:59:59.000Z

    This publication Nuclear Reactors and Technology (NRT) announces on a monthly basis the current worldwide information available from the open literature on nuclear reactors and technology, including all aspects of power reactors, components and accessories, fuel elements, control systems, and materials. This publication contains the abstracts of DOE reports, journal articles, conference papers, patents, theses, and monographs added to the Energy Science and Technology Database during the past month. Also included are US information obtained through acquisition programs or interagency agreements and international information obtained through the International Energy Agency`s Energy Technology Data Exchange or government-to-government agreements. The digests in NRT and other citations to information on nuclear reactors back to 1948 are available for online searching and retrieval on the Energy Science and Technology Database and Nuclear Science Abstracts (NSA) database. Current information, added daily to the Energy Science and Technology Database, is available to DOE and its contractors through the DOE Integrated Technical Information System. Customized profiles can be developed to provide current information to meet each user`s needs.

  18. NETL - Chemical Looping Reactor

    ScienceCinema (OSTI)

    None

    2014-06-26T23:59:59.000Z

    NETL's Chemical Looping Reactor unit is a high-temperature integrated CLC process with extensive instrumentation to improve computational simulations. A non-reacting test unit is also used to study solids flow at ambient temperature. The CLR unit circulates approximately 1,000 pounds per hour at temperatures around 1,800 degrees Fahrenheit.

  19. Thermal Reactor Safety

    SciTech Connect (OSTI)

    Not Available

    1980-06-01T23:59:59.000Z

    Information is presented concerning fire risk and protection; transient thermal-hydraulic analysis and experiments; class 9 accidents and containment; diagnostics and in-service inspection; risk and cost comparison of alternative electric energy sources; fuel behavior and experiments on core cooling in LOCAs; reactor event reporting analysis; equipment qualification; post facts analysis of the TMI-2 accident; and computational methods.

  20. Nuclear reactor building

    DOE Patents [OSTI]

    Gou, Perng-Fei (Saratoga, CA); Townsend, Harold E. (Campbell, CA); Barbanti, Giancarlo (Sirtori, IT)

    1994-01-01T23:59:59.000Z

    A reactor building for enclosing a nuclear reactor includes a containment vessel having a wetwell disposed therein. The wetwell includes inner and outer walls, a floor, and a roof defining a wetwell pool and a suppression chamber disposed thereabove. The wetwell and containment vessel define a drywell surrounding the reactor. A plurality of vents are disposed in the wetwell pool in flow communication with the drywell for channeling into the wetwell pool steam released in the drywell from the reactor during a LOCA for example, for condensing the steam. A shell is disposed inside the wetwell and extends into the wetwell pool to define a dry gap devoid of wetwell water and disposed in flow communication with the suppression chamber. In a preferred embodiment, the wetwell roof is in the form of a slab disposed on spaced apart support beams which define therebetween an auxiliary chamber. The dry gap, and additionally the auxiliary chamber, provide increased volume to the suppression chamber for improving pressure margin.

  1. Nuclear reactor building

    DOE Patents [OSTI]

    Gou, P.F.; Townsend, H.E.; Barbanti, G.

    1994-04-05T23:59:59.000Z

    A reactor building for enclosing a nuclear reactor includes a containment vessel having a wetwell disposed therein. The wetwell includes inner and outer walls, a floor, and a roof defining a wetwell pool and a suppression chamber disposed there above. The wetwell and containment vessel define a drywell surrounding the reactor. A plurality of vents are disposed in the wetwell pool in flow communication with the drywell for channeling into the wetwell pool steam released in the drywell from the reactor during a LOCA for example, for condensing the steam. A shell is disposed inside the wetwell and extends into the wetwell pool to define a dry gap devoid of wetwell water and disposed in flow communication with the suppression chamber. In a preferred embodiment, the wetwell roof is in the form of a slab disposed on spaced apart support beams which define there between an auxiliary chamber. The dry gap, and additionally the auxiliary chamber, provide increased volume to the suppression chamber for improving pressure margin. 4 figures.

  2. Fossil fuel furnace reactor

    DOE Patents [OSTI]

    Parkinson, William J. (Los Alamos, NM)

    1987-01-01T23:59:59.000Z

    A fossil fuel furnace reactor is provided for simulating a continuous processing plant with a batch reactor. An internal reaction vessel contains a batch of shale oil, with the vessel having a relatively thin wall thickness for a heat transfer rate effective to simulate a process temperature history in the selected continuous processing plant. A heater jacket is disposed about the reactor vessel and defines a number of independent controllable temperature zones axially spaced along the reaction vessel. Each temperature zone can be energized to simulate a time-temperature history of process material through the continuous plant. A pressure vessel contains both the heater jacket and the reaction vessel at an operating pressure functionally selected to simulate the continuous processing plant. The process yield from the oil shale may be used as feedback information to software simulating operation of the continuous plant to provide operating parameters, i.e., temperature profiles, ambient atmosphere, operating pressure, material feed rates, etc., for simulation in the batch reactor.

  3. NETL - Chemical Looping Reactor

    SciTech Connect (OSTI)

    None

    2013-07-24T23:59:59.000Z

    NETL's Chemical Looping Reactor unit is a high-temperature integrated CLC process with extensive instrumentation to improve computational simulations. A non-reacting test unit is also used to study solids flow at ambient temperature. The CLR unit circulates approximately 1,000 pounds per hour at temperatures around 1,800 degrees Fahrenheit.

  4. Reactor Monitoring with Neutrinos

    E-Print Network [OSTI]

    M. Cribier

    2007-04-06T23:59:59.000Z

    The fundamental knowledge on neutrinos acquired in the recent years open the possibility of applied neutrino physics. Among it the automatic and non intrusive monitoring of nuclear reactor by its antineutrino signal could be very valuable to IAEA in charge of the control of nuclear power plants. Several efforts worldwide have already started.

  5. Laser spectroscopic studies of state-dependent collisional quenching of the lifetimes of metastable antiprotonic helium atoms

    E-Print Network [OSTI]

    Hori, M; Torii, H A; Ishikawa, T; Maas, F E; Yamazaki, T; Eades, John; Widmann, E; Kumakara, M; Morita, N; Sugai, I; Horváth, D; Ketzer, B; Hartmann, F J; Maierl, C; Hasinoff, M D; Von Egidy, T; Tamura, H

    1998-01-01T23:59:59.000Z

    Laser spectroscopic studies of state-dependent collisional quenching of the lifetimes of metastable antiprotonic helium atoms

  6. Atomistic studies of formation and diffusion of helium clusters and bubbles in BCC iron

    SciTech Connect (OSTI)

    Stewart, David M [ORNL; Stoller, Roger E [ORNL; Osetskiy, Yury N [ORNL

    2011-01-01T23:59:59.000Z

    In fusion applications, helium created by transmutation plays an important role in the response of reduced-activation ferritic/martensitic (RAFM) steels to neutron radiation damage. We have performed extensive atomistic simulations using the ORNL 3-body Fe He interatomic potential combined with three interatomic potentials for the iron matrix. Some of the results obtained are summarized in this review. Interstitial helium is very mobile and coalesces together to form interstitial clusters. We have investigated the mobility of these clusters. When an interstitial He cluster reaches sufficient size, it punches out an Fe interstitial, creating an immobile helium vacancy cluster. If more helium atoms join it, more Fe interstitials can be created; the He V defect is a nascent bubble. These mechanisms are investigated together in simulations that examine the nucleation of He defects. Mobile interstitial He clusters and helium bubbles 1 to 6 nm across are also simulated separately. Results are compared based on temperature and interatomic potentials used.

  7. Terracentric Nuclear Fission Reactor: Background, Basis, Feasibility, Structure, Evidence, and Geophysical Implications

    E-Print Network [OSTI]

    J. Marvin Herndon

    2013-12-31T23:59:59.000Z

    The background, basis, feasibility, structure, evidence, and geophysical implications of a naturally occurring Terracentric nuclear fission georeactor are reviewed. For a nuclear fission reactor to exist at the center of the Earth, all of the following conditions must be met: (1) There must originally have been a substantial quantity of uranium within Earth's core; (2) There must be a natural mechanism for concentrating the uranium; (3) The isotopic composition of the uranium at the onset of fission must be appropriate to sustain a nuclear fission chain reaction; (4) The reactor must be able to breed a sufficient quantity of fissile nuclides to permit operation over the lifetime of Earth to the present; (5) There must be a natural mechanism for the removal of fission products; (6) There must be a natural mechanism for removing heat from the reactor; (7) There must be a natural mechanism to regulate reactor power level, and; (8) The location of the reactor or must be such as to provide containment and prevent meltdown. Herndon's georeactor alone is shown to meet those conditions. Georeactor existence evidence based upon helium measurements and upon antineutrino measurements is described. Geophysical implications discussed include georeactor origin of the geomagnetic field, geomagnetic reversals from intense solar outbursts and severe Earth trauma, as well as georeactor heat contributions to global dynamics.

  8. cpp header will be provided by the publisher Properties of Dense Fluid Hydrogen and Helium in Giant Gas

    E-Print Network [OSTI]

    Militzer, Burkhard

    cpp header will be provided by the publisher Properties of Dense Fluid Hydrogen and Helium in Giant molecular dynamics, equation of state, giant gas planets, hydrogen-helium mix- tures PACS 61.20.Ja, 61.25.Em, 61.25.Mv, 61.20.-p Equilibrium properties of hydrogen-helium mixtures under thermodynamic conditions

  9. Helium isotopes in historical lavas from Mount Vesuvius Comment on `Noble gas isotopic ratios from historical lavas

    E-Print Network [OSTI]

    Graham, David W.

    Discussion Helium isotopes in historical lavas from Mount Vesuvius Comment on `Noble gas isotopic. Introduction Helium isotope results recently published by Tedesco et al. [1] appear to show a decrease in 3 He. Results Helium isotope results from our laboratory are reported in Table 1. The 3 He/4 He ratio has been

  10. Helium atom scattering from isolated CO molecules on copper(001) A. P. Graham, F. Hofmann, and J. P. Toennies

    E-Print Network [OSTI]

    Manson, Joseph R.

    Helium atom scattering from isolated CO molecules on copper(001) A. P. Graham, F. Hofmann, and J. P 1996 Angular distributions have been measured for helium atoms scattering from isolated CO molecules with difficulties. Helium atom scattering HAS , on the other hand, can, at least for simple systems, also detect

  11. Classical Helium Atom with Radiation Reaction Universit`a degli Studi di Milano, Corso di Laurea in Fisica,

    E-Print Network [OSTI]

    Galgani, Luigi

    Classical Helium Atom with Radiation Reaction G. Camelio Universit`a degli Studi di Milano, Corso: November 24, 2011) Abstract We study a classical model of Helium atom in which, in addition to the Coulomb (see for example Refs. 1­8), in this paper we take into account, for the case of the Helium atom

  12. SOLAR WIND HELIUM ABUNDANCE AS A FUNCTION OF SPEED AND HELIOGRAPHIC LATITUDE: VARIATION THROUGH A SOLAR CYCLE

    E-Print Network [OSTI]

    Richardson, John

    SOLAR WIND HELIUM ABUNDANCE AS A FUNCTION OF SPEED AND HELIOGRAPHIC LATITUDE: VARIATION THROUGH of the variation of the relative abundance of helium to hydrogen in the solar wind as a function of solar wind theoretical work in which enhancements of coronal helium lead to stagnation of the escaping proton flux

  13. Helium isotopes on the Pacific-Antarctic ridge (52.541.5S) Manuel A. Moreira,1

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Helium isotopes on the Pacific-Antarctic ridge (52.5°­41.5°S) Manuel A. Moreira,1 Laure Dosso,2; published 24 May 2008. [1] The first isotopic data and concentrations of helium are reported for the Pacific two mantles with slightly different helium isotopic ratios (96,595 ± 1520 and 100,347 ± 2330

  14. Helium atom scattering from isolated CO molecules on copper(001) A. P. Graham, F. Hofmann, and J. P. Toennies

    E-Print Network [OSTI]

    Manson, Joseph R.

    Helium atom scattering from isolated CO molecules on copper(001) A. P. Graham, F. Hofmann, and J. P 1996! Angular distributions have been measured for helium atoms scattering from isolated CO molecules with difficulties. Helium atom scattering ~HAS!, on the other hand, can, at least for simple systems, also detect

  15. RETRACTABLE HELIUM TRANSFER LINES FOR THE FLOATING FUSION Zhukovsky A., Garnier D.T.,* Fishman V., Lations R.

    E-Print Network [OSTI]

    CR06-45 RETRACTABLE HELIUM TRANSFER LINES FOR THE FLOATING FUSION MAGNET Zhukovsky A., Garnier D. When the magnet is low- ered, an inlet line, pre-cooled by liquid helium, is reinserted and re of helium at room temperature to 12.5 MPa. A lead-fiberglass high heat capacity radiation shield surrounds

  16. Reactor vessel support system. [LMFBR

    DOE Patents [OSTI]

    Golden, M.P.; Holley, J.C.

    1980-05-09T23:59:59.000Z

    A reactor vessel support system includes a support ring at the reactor top supported through a box ring on a ledge of the reactor containment. The box ring includes an annular space in the center of its cross-section to reduce heat flow and is keyed to the support ledge to transmit seismic forces from the reactor vessel to the containment structure. A coolant channel is provided at the outside circumference of the support ring to supply coolant gas through the keyways to channels between the reactor vessel and support ledge into the containment space.

  17. Nuclear reactor construction with bottom supported reactor vessel

    DOE Patents [OSTI]

    Sharbaugh, John E. (Bullskin Township, Fayette County, PA)

    1987-01-01T23:59:59.000Z

    An improved liquid metal nuclear reactor construction has a reactor core and a generally cylindrical reactor vessel for holding a large pool of low pressure liquid metal coolant and housing the core within the pool. The reactor vessel has an open top end, a closed flat bottom end wall and a continuous cylindrical closed side wall interconnecting the top end and bottom end wall. The reactor also has a generally cylindrical concrete containment structure surrounding the reactor vessel and being formed by a cylindrical side wall spaced outwardly from the reactor vessel side wall and a flat base mat spaced below the reactor vessel bottom end wall. A central support pedestal is anchored to the containment structure base mat and extends upwardly therefrom to the reactor vessel and upwardly therefrom to the reactor core so as to support the bottom end wall of the reactor vessel and the lower end of the reactor core in spaced apart relationship above the containment structure base mat. Also, an annular reinforced support structure is disposed in the reactor vessel on the bottom end wall thereof and extends about the lower end of the core so as to support the periphery thereof. In addition, an annular support ring having a plurality of inward radially extending linear members is disposed between the containment structure base mat and the bottom end of the reactor vessel wall and is connected to and supports the reactor vessel at its bottom end on the containment structure base mat so as to allow the reactor vessel to expand radially but substantially prevent any lateral motions that might be imposed by the occurrence of a seismic event. The reactor construction also includes a bed of insulating material in sand-like granular form, preferably being high density magnesium oxide particles, disposed between the containment structure base mat and the bottom end wall of the reactor vessel and uniformly supporting the reactor vessel at its bottom end wall on the containment structure base mat so as to insulate the reactor vessel bottom end wall from the containment structure base mat and allow the reactor vessel bottom end wall to freely expand as it heats up while providing continuous support thereof. Further, a deck is supported upon the side wall of the containment structure above the top open end of the reactor vessel, and a plurality of serially connected extendible and retractable annular bellows extend between the deck and the top open end of the reactor vessel and flexibly and sealably interconnect the reactor vessel at its top end to the deck. An annular guide ring is disposed on the containment structure and extends between its side wall and the top open end of the reactor vessel for providing lateral support of the reactor vessel top open end by limiting imposition of lateral loads on the annular bellows by the occurrence of a lateral seismic event.

  18. 05/22/2006 12:33 PMnews @ nature.com -Chaos could keep fusion under control -A leaky magnetic bottle may prove key to making a reactor. Page 1 of 3http://www.nature.com/news/2006/060522/full/060522-2.html

    E-Print Network [OSTI]

    ) achieve its goal of generating net energy from fusion. Fusion occurs when two light elements, usually hydrogen, collide to form a new element, usually helium, releasing an enormous amount of energy and produces less long-lived radioactive waste. Scientists have worked for decades to build a fusion reactor

  19. Nuclear reactor safety device

    DOE Patents [OSTI]

    Hutter, E.

    1983-08-15T23:59:59.000Z

    A safety device is described for use in a nuclear reactor for axially repositioning a control rod with respect to the reactor core in the event of a thermal excursion. It comprises a laminated strip helically configured to form a tube, said tube being in operative relation to said control rod. The laminated strip is formed of at least two materials having different thermal coefficients of expansion, and is helically configured such that the material forming the outer lamina of the tube has a greater thermal coefficient of expansion than the material forming the inner lamina of said tube. In the event of a thermal excursion the laminated strip will tend to curl inwardly so that said tube will increase in length, whereby as said tube increases in length it exerts a force on said control rod to axially reposition said control rod with respect to said core.

  20. Fusion reactor pumped laser

    DOE Patents [OSTI]

    Jassby, D.L.

    1987-09-04T23:59:59.000Z

    A nuclear pumped laser capable of producing long pulses of very high power laser radiation is provided. A toroidal fusion reactor provides energetic neutrons which are slowed down by a moderator. The moderated neutrons are converted to energetic particles capable of pumping a lasing medium. The lasing medium is housed in an annular cell surrounding the reactor. The cell includes an annular reflecting mirror at the bottom and an annular output window at the top. A neutron reflector is disposed around the cell to reflect escaping neutrons back into the cell. The laser radiation from the annular window is focused onto a beam compactor which generates a single coherent output laser beam. 10 figs.

  1. Spherical torus fusion reactor

    DOE Patents [OSTI]

    Peng, Yueng-Kay M. (Oak Ridge, TN)

    1989-01-01T23:59:59.000Z

    A fusion reactor is provided having a near spherical-shaped plasma with a modest central opening through which straight segments of toroidal field coils extend that carry electrical current for generating a toroidal magnet plasma confinement fields. By retaining only the indispensable components inboard of the plasma torus, principally the cooled toroidal field conductors and in some cases a vacuum containment vessel wall, the fusion reactor features an exceptionally small aspect ratio (typically about 1.5), a naturally elongated plasma cross section without extensive field shaping, requires low strength magnetic containment fields, small size and high beta. These features combine to produce a spherical torus plasma in a unique physics regime which permits compact fusion at low field and modest cost.

  2. Measurements of neutral helium density in helicon plasmas

    SciTech Connect (OSTI)

    Houshmandyar, Saeid; Sears, Stephanie H.; Thakur, Saikat Chakraborty; Carr, Jerry Jr.; Galante, Matthew E.; Scime, Earl E. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506-6315 (United States)

    2010-10-15T23:59:59.000Z

    Laser-induced-fluorescence (LIF) is used to measure the density of helium atoms in a helicon plasma source. For a pump wavelength of 587.725 nm (vacuum) and laser injection along the magnetic field, the LIF signal exhibits a signal decrease at the Doppler shifted central wavelength. The drop in signal results from the finite optical depth of the plasma and the magnitude of the decrease is proportional to the density of excited state neutral atoms. Using Langmuir probe measurements of plasma density and electron temperature and a collisional-radiative model, the absolute ground state neutral density is calculated from the optical depth measurements. Optimal plasma performance, i.e., the largest neutral depletion on the axis of the system, is observed for antenna frequencies of 13.0 and 13.5 MHz and magnetic field strengths of 550-600 G.

  3. Options for Cryogenic Load Cooling with Forced Flow Helium Circulation

    SciTech Connect (OSTI)

    Peter Knudsen, Venkatarao Ganni, Roberto Than

    2012-06-01T23:59:59.000Z

    Cryogenic pumps designed to circulate super-critical helium are commonly deemed necessary in many super-conducting magnet and other cooling applications. Acknowledging that these pumps are often located at the coldest temperature levels, their use introduces risks associated with the reliability of additional rotating machinery and an additional load on the refrigeration system. However, as it has been successfully demonstrated, this objective can be accomplished without using these pumps by the refrigeration system, resulting in lower system input power and improved reliability to the overall cryogenic system operations. In this paper we examine some trade-offs between using these pumps vs. using the refrigeration system directly with examples of processes that have used these concepts successfully and eliminated using such pumps

  4. Jaynes-Cummings Models with trapped electrons on liquid Helium

    E-Print Network [OSTI]

    Miao Zhang; H. Y. Jia; L. F. Wei

    2009-09-01T23:59:59.000Z

    Jaynes-Cummings model is a typical model in quantum optics and has been realized with various physical systems (e.g, cavity QED, trapped ions, and circuit QED etc..) of two-level atoms interacting with quantized bosonic fields. Here, we propose a new implementation of this model by using a single classical laser beam to drive an electron floating on liquid Helium. Two lowest levels of the {\\it vertical} motion of the electron acts as a two-level "atom", and the quantized vibration of the electron along one of the {\\it parallel} directions, e.g., $x$-direction, serves the bosonic mode. These two degrees of freedom of the trapped electron can be coupled together by using a classical laser field. If the frequencies of the applied laser fields are properly set, the desirable Jaynes-Cummings models could be effectively realized.

  5. Hyperfine Structure of S-States in Muonic Helium Ion

    E-Print Network [OSTI]

    A. P. Martynenko

    2007-10-17T23:59:59.000Z

    Corrections of orders alpha^5 and alpha^6 are calculated in the hyperfine splittings of 1S and 2S - energy levels in the ion of muonic helium. The electron vacuum polarization effects, the nuclear structure corrections and recoil corrections are taken into account. The obtained numerical values of the hyperfine splittings -1334.56 meV (1S state), -166.62 meV (2S state) can be considered as a reliable estimate for the comparison with the future experimental data. The hyperfine splitting interval Delta_{12}=(8 Delta E^{hfs}(2S)- Delta E^{hfs}(1S)) = 1.64 meV can be used for the check of quantum electrodynamics.

  6. Nuclear fusion in muonic deuterium-helium complex

    E-Print Network [OSTI]

    V. M. Bystritsky; M. Filipowicz; V. V. Gerasimov; P. E. Knowles; F. Mulhauser; N. P. Popov; V. A. Stolupin; V. P. Volnykh; J. Wozniak

    2005-06-22T23:59:59.000Z

    Experimental study of the nuclear fusion reaction in charge-asymmetrical d-mu-3He complex is presented. The 14.6 MeV protons were detected by three pairs of Si(dE-E) telescopes placed around the cryogenic target filled with the deuterium + helium-3 gas at 34 K. The 6.85 keV gamma rays emitted during the de-excitation of d-mu-3He complex were detected by a germanium detector. The measurements were performed at two target densities, 0.0585 and 0.169 (relative to liquid hydrogen density) with an atomic concentration of 3He c=0.0469. The values of the effective rate of nuclear fusion in d-mu-3He was obtained for the first time, and the J=0 nuclear fusion rate in d-mu-3He was derived.

  7. Interactions of mobile helium clusters with surfaces and grain boundaries of plasma-exposed tungsten

    SciTech Connect (OSTI)

    Hu, Lin; Maroudas, Dimitrios, E-mail: maroudas@ecs.umass.edu [Department of Chemical Engineering, University of Massachusetts, Amherst, Massachusetts 01003-9303 (United States); Hammond, Karl D.; Wirth, Brian D. [Department of Nuclear Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States)

    2014-05-07T23:59:59.000Z

    We report results of atomistic computations for the interactions of small mobile helium clusters (He{sub n}) with free surfaces and grain boundaries (GBs) in tungsten toward development of continuum drift-diffusion-reaction models for the dynamics of mobile helium clusters in plasma-exposed tungsten. Molecular-statics (MS) simulations based on reliable many-body interatomic potentials are carried out for He{sub n} (1???n???7) clusters near sinks to obtain the potential energy profiles of the He{sub n} clusters as a function of the clusters' center-of-mass distance from a sink. Sinks investigated include surfaces, GBs, and regions in the vicinity of junctions where GBs intersect free surfaces. Elastic interaction potentials based on elastic inclusion theory provide an excellent description of the MS results for the cluster-sink interactions. The key parameter in the elastic models is the sink segregation strength, which is found to increase with increasing cluster size. Such cluster-sink interactions are responsible for the migration of small helium clusters by drift and for helium segregation on surfaces and grain boundaries in tungsten. Such helium segregation on sinks is observed in large-scale molecular-dynamics simulations of helium aggregation in model polycrystalline tungsten at 933?K upon helium implantation.

  8. Chemical reactions studied at ultra-low temperature in liquid helium clusters

    SciTech Connect (OSTI)

    Huisken, Friedrich; Krasnokutski, Serge A. [Laboratory Astrophysics Group of the Max Planck Institute for Astronomy at the University of Jena, Institute of Solid State Physics, Helmholtzweg 3, D-07743 Jena (Germany)

    2012-11-27T23:59:59.000Z

    Low-temperature reaction rates are important ingredients for astrophysical reaction networks modeling the formation of interstellar matter in molecular clouds. Unfortunately, such data is difficult to obtain by experimental means. In an attempt to study low-temperature reactions of astrophysical interest, we have investigated relevant reactions at ultralow temperature in liquid helium droplets. Being prepared by supersonic expansion of helium gas at high pressure through a nozzle into a vacuum, large helium clusters in the form of liquid droplets constitute nano-sized reaction vessels for the study of chemical reactions at ultra-low temperature. If the normal isotope {sup 4}He is used, the helium droplets are superfluid and characterized by a constant temperature of 0.37 K. Here we present results obtained for Mg, Al, and Si reacting with O{sub 2}. Mass spectrometry was employed to characterize the reaction products. As it may be difficult to distinguish between reactions occurring in the helium droplets before they are ionized and ion-molecule reactions taking place after the ionization, additional techniques were applied to ensure that the reactions actually occurred in the helium droplets. This information was provided by measuring the chemiluminescence light emitted by the products, the evaporation of helium atoms by the release of the reaction heat, or by laser-spectroscopic identification of the reactants and products.

  9. Nuclear reactor sealing system

    DOE Patents [OSTI]

    McEdwards, James A. (Calabasas, CA)

    1983-01-01T23:59:59.000Z

    A liquid metal-cooled nuclear reactor sealing system. The nuclear reactor includes a vessel sealed at its upper end by a closure head. The closure head comprises at least two components, one of which is rotatable; and the two components define an annulus therebetween. The sealing system includes at least a first and second inflatable seal disposed in series in an upper portion of the annulus. The system further includes a dip seal extending into a body of insulation located adjacent a bottom portion of the closure head. The dip seal comprises a trough formed by a lower portion of one of the components, and a seal blade pendently supported from the other component and extending downwardly into the trough. A body of liquid metal is contained in the trough which submerges a portion of the seal blade. The seal blade is provided with at least one aperture located above the body of liquid metal for providing fluid communication between the annulus intermediate the dip seal and the inflatable seals, and a body of cover gas located inside the vessel. There also is provided means for introducing a purge gas into the annulus intermediate the inflatable seals and the seal blade. The purge gas is introduced in an amount sufficient to substantially reduce diffusion of radioactive cover gas or sodium vapor up to the inflatable seals. The purge gas mixes with the cover gas in the reactor vessel where it can be withdrawn from the vessel for treatment and recycle to the vessel.

  10. Strategic Need for Multi-Purpose Thermal Hydraulic Loop for Support of Advanced Reactor Technologies

    SciTech Connect (OSTI)

    James E. O'Brien; Piyush Sabharwall; Su-Jong Yoon; Gregory K. Housley

    2014-09-01T23:59:59.000Z

    This report presents a conceptual design for a new high-temperature multi fluid, multi loop test facility for the INL to support thermal hydraulic, materials, and thermal energy storage research for nuclear and nuclear-hybrid applications. In its initial configuration, the facility will include a high-temperature helium loop, a liquid salt loop, and a hot water/steam loop. The three loops will be thermally coupled through an intermediate heat exchanger (IHX) and a secondary heat exchanger (SHX). Research topics to be addressed with this facility include the characterization and performance evaluation of candidate compact heat exchangers such as printed circuit heat exchangers (PCHEs) at prototypical operating conditions, flow and heat transfer issues related to core thermal hydraulics in advanced helium-cooled and salt-cooled reactors, and evaluation of corrosion behavior of new cladding materials and accident-tolerant fuels for LWRs at prototypical conditions. Based on its relevance to advanced reactor systems, the new facility has been named the Advanced Reactor Technology Integral System Test (ARTIST) facility. Research performed in this facility will advance the state of the art and technology readiness level of high temperature intermediate heat exchangers (IHXs) for nuclear applications while establishing the INL as a center of excellence for the development and certification of this technology. The thermal energy storage capability will support research and demonstration activities related to process heat delivery for a variety of hybrid energy systems and grid stabilization strategies. Experimental results obtained from this research will assist in development of reliable predictive models for thermal hydraulic design and safety codes over the range of expected advanced reactor operating conditions. Proposed/existing IHX heat transfer and friction correlations and criteria will be assessed with information on materials compatibility and instrumentation needs. The experimental database will guide development of appropriate predictive methods and be available for code verification and validation (V&V) related to these systems.

  11. The Helium abundance and Delta Y / Delta Z in Lower Main Sequence stars

    E-Print Network [OSTI]

    Luca Casagrande; Chris Flynn; Laura Portinari; Leo Girardi; Raul Jimenez

    2007-12-10T23:59:59.000Z

    We use nearby K dwarf stars to measure the helium-to-metal enrichment ratio, a diagnostic of the chemical history of the Solar Neighbourhood. Our sample of K dwarfs has homogeneously determined effective temperatures, bolometric luminosities and metallicities, allowing us to fit each star to the appropriate stellar isochrone and determine its helium content indirectly. We use a newly computed set of Padova isochrones which cover a wide range of helium and metal content. Our theoretical isochrones have been checked against a congruous set of main sequence binaries with accurately measured masses, to discuss and validate their range of applicability. We find that the stellar masses deduced from the isochrones are usually in excellent agreement with empirical measurements. Good agreement is also found with empirical mass-luminosity relations. Despite fitting the masses of the stars very well, we find that anomalously low helium content (lower than primordial helium) is required to fit the luminosities and temperatures of the metal poor K dwarfs, while more conventional values of the helium content are derived for the stars around solar metallicity. We have investigated the effect of diffusion in stellar models and LTE assumption in deriving metallicities. Neither of these is able to resolve the low helium problem alone and only marginally if the cumulated effects are included, unless we assume a mixing-length which is strongly decreasing with metallicity. Further work in stellar models is urgently needed. The helium-to-metal enrichment ratio is found to be Delta Y / Delta Z = 2.1 +/- 0.9 around and above solar metallicity, consistent with previous studies, whereas open problems still remain at the lowest metallicities. Finally, we determine the helium content for a set of planetary host stars.

  12. THE EFFECTS OF CURVATURE AND EXPANSION ON HELIUM DETONATIONS ON WHITE DWARF SURFACES

    SciTech Connect (OSTI)

    Moore, Kevin; Bildsten, Lars [Department of Physics, University of California, Santa Barbara, CA (United States); Townsley, Dean M. [Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL (United States)

    2013-10-20T23:59:59.000Z

    Accreted helium layers on white dwarfs have been highlighted for many decades as a possible site for a detonation triggered by a thermonuclear runaway. In this paper, we find the minimum helium layer thickness that will sustain a steady laterally propagating detonation and show that it depends on the density and composition of the helium layer, specifically {sup 12}C and {sup 16}O. Detonations in these thin helium layers have speeds slower than the Chapman-Jouget (CJ) speed from complete helium burning, v{sub CJ} = 1.5 × 10{sup 9} cm s{sup –1}. Though gravitationally unbound, the ashes still have unburned helium (?80% in the thinnest cases) and only reach up to heavy elements such as {sup 40}Ca, {sup 44}Ti, {sup 48}Cr, and {sup 52}Fe. It is rare for these thin shells to generate large amounts of {sup 56}Ni. We also find a new set of solutions that can propagate in even thinner helium layers when {sup 16}O is present at a minimum mass fraction of ?0.07. Driven by energy release from ? captures on {sup 16}O and subsequent elements, these slow detonations only create ashes up to {sup 28}Si in the outer detonated He shell. We close by discussing how the unbound helium burning ashes may create faint and fast 'Ia' supernovae as well as events with virtually no radioactivity, and speculate on how the slower helium detonation velocities impact the off-center ignition of a carbon detonation that could cause a Type Ia supernova in the double detonation scenario.

  13. Experimental evidence for the suitability of ELMing H-mode operation in ITER with regard to core transport of helium

    SciTech Connect (OSTI)

    Wade, M.R.; Hillis, D.L. [Oak Ridge National Lab., TN (United States); Burrell, K.H. [General Atomics, San Diego, CA (United States)] [and others

    1996-09-01T23:59:59.000Z

    Studies have been conducted in DIII-D to assess the viability of the ITER design with regard to helium ash removal, including both global helium exhaust studies and detailed helium transport studies. With respect to helium ash accumulation, the results are encouraging for successful operation of ITER in ELMing H-mode plasmas with conventional high-recycling divertor operation. Helium can be removed from the plasma core with a characteristic time constant of {approximately} 8 energy confinement times, even with a central source of helium. Furthermore, the exhaust rate is limited by the pumping efficiency of the system and not by transport of helium within the plasma core. Helium transport studies have shown that D{sub He}/X{sub eff} {approximately} 1 in all confinement regimes studied to date and there is little dependence of D{sub He}/X{sub eff} on normalized gyroradius in dimensionless scaling studies, suggesting that D{sub He}/X{sub eff} will be {approximately} 1 in ITER. These observations suggest that helium transport within the plasma core should be sufficient to prevent unacceptable fuel dilution in ITER. However, helium exhaust is also strongly dependent on many factors (e.g., divertor plasma conditions, plasma and baffling geometry, flux amplification, pumping speed, etc.) that are difficult to extrapolate. Studies have revealed the helium diffusivity decreases as the plasma density increases, which is unfavorable to ITER`s extremely high density operation.

  14. Helium effects on the reweldability and low cycle fatigue properties of welded joints for type Cr16Ni11Mo3Ti and 316L(N) stainless steels

    SciTech Connect (OSTI)

    Fabritsiev, S.A. [D.V. Efremov Inst. of Electrophysical Apparatus, St. Petersburg (Russian Federation); Laan, J.G. van der [Netherlands Energy Research Foundation, Petten (Netherlands)

    1996-12-31T23:59:59.000Z

    The feasibility of welding neutron irradiated modules and tubes for repair or replacement purposes is one of the key problems in life time estimates for austenitic steel, intended for use as structural material in the first wall , blanket and vacuum vessel of the International Thermonuclear Experimental Reactor (ITER). Here, the reweldability of austenitic alloys has been studied for flat specimens of Cr16Ni11Mo3Ti (Russian) and 316L(N)-SPH (European Union) which have been implanted with helium using cyclotron facilities. Specimens with typical thicknesses of 1 mm have been implanted up the helium concentrations of 50, 100, 300 and 860 appm on both sides. Electron beam welding of Cr16Ni11Mo3Ti resulted in weld cracking for specimens with the highest helium concentration of 860 appm, unlike the 316L-SPH material in similar conditions. A reduction in fatigue life in low cycle fatigue was found to be more significant for welded joints of Cr16Ni11Mo3Ti material.

  15. The muonic helium atom as a classical three-body problem T.J.Stuchi 1 , A.C.B.Antunes 1 and M.A.Andreu 2

    E-Print Network [OSTI]

    Barcelona, Universitat de

    The muonic helium atom as a classical three-body problem T.J.Stuchi 1 , A.C.B.Antunes 1 and M problem of the muonic helium atom, a helium atom with one of its electrons replaced by a muon. Firstly, we establish the connection of the model with the one-dimensional frozen planetary approximation of the helium

  16. Nuclear reactor engineering: Reactor systems engineering. Fourth edition, Volume Two

    SciTech Connect (OSTI)

    Glasstone, S.; Sesonske, A.

    1994-12-31T23:59:59.000Z

    This new edition of this classic reference combines broad yet in-depth coverage of nuclear engineering principles with practical descriptions of their application in the design and operation of nuclear power plants. Extensively updated, the fourth edition includes new materials on reactor safety and risk analysis, regulation, fuel management, waste management and operational aspects of nuclear power. This volume contains the following: the systems concept, design decisions, and information tools; energy transport; reactor fuel management and energy cost considerations; environmental effects of nuclear power and waste management; nuclear reactor safety and regulation; power reactor systems; plant operations; and advanced plants and the future.

  17. Modular Pebble Bed Reactor High Temperature Gas Reactor

    E-Print Network [OSTI]

    Built · Site Assembled · On--line Refueling · Modules added to meet demand. · No Reprocessing · High Experiments · Non-Proliferation · Safeguards · Waste Disposal · Reactor Research/ Demonstration Facility

  18. Development of a Mass Flowmeter based on the Coriolis Acceleration for Liquid, Supercritical and Superfluid Helium

    E-Print Network [OSTI]

    De Jonge, T; Rivetti, A; Serio, L

    2002-01-01T23:59:59.000Z

    Beginning in the 1980's, Coriolis meters have gained generalised acceptance in liquid applications with a worldwide installed base of over 300,000 units. To meet the demands of cryogenic applications below 20 K, off-the-shelf Coriolis meters have been used, with minor design modifications and operational changes. The meters were originally calibrated on water and tested on liquid helium at 4.5 K, supercritical helium around 5 K and superfluid helium below 2 K. The meters maintain their intrinsic robustness and accuracy of better than 1% of measured value; accuracy is independent of density and temperature.

  19. Effects of helium content of microstructural development in Type 316 stainless steel under neutron irradiation

    SciTech Connect (OSTI)

    Maziasz, P.J.

    1985-11-01T23:59:59.000Z

    This work investigated the sensitivity of microstructural evolution, particularly precipitate development, to increased helium content during thermal aging and during neutron irradiation. Helium (110 at. ppM) was cold preinjected into solution annealed (SA) DO-heat type 316 stainess steel (316) via cyclotron irradiation. These specimens were then exposed side by side with uninjected samples. Continuous helium generation was increased considerably relative to EBR-II irradiation by irradiation in HFIR. Data were obtained from quantitative analytical electron microscopy (AEM) in thin foils and on extraction replicas. 480 refs., 86 figs., 19 tabs.

  20. Thermionic Reactor Design Studies

    SciTech Connect (OSTI)

    Schock, Alfred

    1994-06-01T23:59:59.000Z

    During the 1960's and early 70's the author performed extensive design studies, analyses, and tests aimed at thermionic reactor concepts that differed significantly from those pursued by other investigators. Those studies, like most others under Atomic Energy Commission (AEC and DOE) and the National Aeronautics and Space Administration (NASA) sponsorship, were terminated in the early 1970's. Some of this work was previously published, but much of it was never made available in the open literature. U.S. interest in thermionic reactors resumed in the early 80's, and was greatly intensified by reports about Soviet ground and flight tests in the late 80's. This recent interest resulted in renewed U.S. thermionic reactor development programs, primarily under Department of Defense (DOD) and Department of Energy (DOE) sponsorship. Since most current investigators have not had an opportunity to study all of the author's previous work, a review of the highlights of that work may be of value to them. The present paper describes some of the author's conceptual designs and their rationale, and the special analytical techniques developed to analyze their performance. The basic designs, first published in 1963, are based on single-cell converters, either double-ended diodes extending over the full height of the reactor core or single-ended diodes extending over half the core height. In that respect they are similar to the thermionic fuel elements employed in the Topaz-2 reactor subsequently developed in the Soviet Union, copies of which were recently imported by the U.S. As in the Topaz-2 case, electrically heated steady-state performance tests of the converters are possible before fueling. Where the author's concepts differed from the later Topaz-2 design was in the relative location of the emitter and the collector. Placing the fueled emitter on the outside of the cylindrical diodes permits much higher axial conductances to reduce ohmic losses in the electrodes of full-core-height diodes. Moreover, placing the fuel on the outside of the diode makes possible reactors with much higher fuel volume fractions, which enable power-flattened fast reactors scalable to very low power levels without the need for life-limiting hydride moderators or the use of efficiency-limiting driver fuel. In addition, with the fuel on the outside its swelling does not increase the emitter diameter or reduce the interelectrode gap. This should permit long lifetimes even with closer spacings, which can significantly improve the system efficiences. This was confirmed by coupled neutronic, thermal, thermionic, and electrical system analyses - some of which are presented in this paper - and by subsequent experiments. A companion paper presented next describes the fabrication and testing of full-scale converter elements, both fueled and unfueled, and summarizes the test results obtained. There is a duplicate copy in the file.

  1. Status of EC solid breeder blanket designs and R&D for DEMO fusion reactors

    SciTech Connect (OSTI)

    Dalle Donne, M. [INR, Karlsruhe (Russian Federation); Anziedi, L.A. [C.R.E., Franscati (Italy); Kwast, H. [ECN, Petten (Netherlands)] [and others

    1994-12-31T23:59:59.000Z

    In the framework of the European Community Fusion Technology Program four blanket concepts for a DEMO reactor are being investigated. DEMO is the next step after ITER. It should ensure tritium self-sufficiency and operate at coolant temperatures high enough to have a reasonable plant efficiency. Further requirements have been specified for the four concepts, namely an average neutron wall load of 2.2 MW/m{sup 2}, a blanket lifetime of 20000 hours and the capability of the blanket segment to withstand the forces caused by a rapid distribution of the plasma current (20 MA to zero in 20 ms), so that after the disruption the segment can still allow a comparison of the various options, in view of reducing this number to two in 1995 and to design and develop modules and articles representative of the chosen blankets to be tested in ITER. The present paper deals with two solid breeder concepts. They have many features in common: both use high pressure helium as coolant and helium to purge the tritium from the breeder material, martensitic steel as structural material and beryllium as neutron multiplier. The configuration of the two blankets are however different: in the B.I.T. (Breeder Inside Tube) concept the breeder material is LiAlO{sub 2} or LiZrO{sub 3} in the form of annular pellets contained in tubes surrounded by beryllium blocks, the coolant helium being outside the tubes, whereas in the B.O.T. (Breeder out of Tube) the breeder and multiplier material are Li{sub 4}SiO{sub 4} and beryllium pebbles forming a mixed bed placed outside the tubes containing the coolant helium.

  2. Enhancement of the helium resonance lines in the solar atmosphere by suprathermal electron excitation I: non-thermal transport of helium ions

    E-Print Network [OSTI]

    G. R. Smith; C. Jordan

    2002-08-16T23:59:59.000Z

    Models of the solar transition region made from lines other than those of helium cannot account for the strength of the helium lines. However, the collisional excitation rates of the helium resonance lines are unusually sensitive to the energy of the exciting electrons. Non-thermal motions in the transition region could drive slowly-ionizing helium ions rapidly through the steep temperature gradient, exposing them to excitation by electrons characteristic of higher temperatures than those describing their ionization state. We present the results of calculations which use a more physical representation of the lifetimes of the ground states of He I and He II than was adopted in earlier work on this process. New emission measure distributions are used to calculate the temperature variation with height. The results show that non-thermal motions can lead to enhancements of the He I and He II resonance line intensities by factors that are comparable with those required. Excitation by non-Maxwellian electron distributions would reduce the effects of non-thermal transport. The effects of non-thermal motions are more consistent with the observed spatial distribution of helium emission than are those of excitation by non-Maxwellian electron distributions alone. In particular, they account better for the observed line intensity ratio I(537.0 A)/I(584.3 A), and its variation with location.

  3. Designing Reactors to Facilitate Decommissioning

    SciTech Connect (OSTI)

    Richard H. Meservey

    2006-06-01T23:59:59.000Z

    Critics of nuclear power often cite issues with tail-end-of-the-fuel-cycle activities as reasons to oppose the building of new reactors. In fact, waste disposal and the decommissioning of large nuclear reactors have proven more challenging than anticipated. In the early days of the nuclear power industry the design and operation of various reactor systems was given a great deal of attention. Little effort, however, was expended on end-of-the-cycle activities, such as decommissioning and disposal of wastes. As early power and test reactors have been decommissioned difficulties with end-of-the-fuel-cycle activities have become evident. Even the small test reactors common at the INEEL were not designed to facilitate their eventual decontamination, decommissioning, and dismantlement. The results are that decommissioning of these facilities is expensive, time consuming, relatively hazardous, and generates large volumes of waste. This situation clearly supports critics concerns about building a new generation of power reactors.

  4. Fast quench reactor and method

    DOE Patents [OSTI]

    Detering, B.A.; Donaldson, A.D.; Fincke, J.R.; Kong, P.C.

    1998-05-12T23:59:59.000Z

    A fast quench reactor includes a reactor chamber having a high temperature heating means such as a plasma torch at its inlet and a restrictive convergent-divergent nozzle at its outlet end. Reactants are injected into the reactor chamber. The resulting heated gaseous stream is then rapidly cooled by passage through the nozzle. This ``freezes`` the desired end product(s) in the heated equilibrium reaction stage. 7 figs.

  5. Optical diagnostic instrument for monitoring etch uniformity during plasma etching of polysilicon in a chlorine-helium plasma

    SciTech Connect (OSTI)

    Hareland, W.A.; Buss, R.J.

    1993-06-01T23:59:59.000Z

    Nonuniform etching is a serious problem in plasma processing of semiconductor materials and has important consequences in the quality and yield of microelectronic components. In many plasmas, etching occurs at a faster rate near the periphery of the wafer, resulting in nonuniform removal of specific materials over the wafer surface. This research was to investigate in situ optical diagnostic techniques for monitoring etch uniformity during plasma processing of microelectronic components. We measured 2-D images of atomic chlorine at 726 nm in a chlorine-helium plasma during plasma etching of polysilicon in a parallel-plate plasma etching reactor. The 3-D distribution of atomic chlorine was determined by Abel inversion of the plasma image. The experimental results showed that the chlorine atomic emission intensity is at a maximum near the outer radius of the plasma and decreases toward the center. Likewise, the actual etch rate, as determined by profilometry on the processed wafer, was approximately 20% greater near the edge of the wafer than at its center. There was a direct correlation between the atomic chlorine emission intensity and the etch rate of polysilicon over the wafer surface. Based on these analyses, 3-D imaging would be a useful diagnostic technique for in situ monitoring of etch uniformity on wafers.

  6. Neutrino Oscillation Studies with Reactors

    E-Print Network [OSTI]

    Petr Vogel; Liangjian Wen; Chao Zhang

    2015-03-03T23:59:59.000Z

    Nuclear reactors are one of the most intense, pure, controllable, cost-effective, and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavors are quantum mechanical mixtures. Over the past several decades reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle $\\theta_{13}$. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.

  7. Neutrino Oscillation Studies with Reactors

    E-Print Network [OSTI]

    Petr Vogel; Liangjian Wen; Chao Zhang

    2015-04-27T23:59:59.000Z

    Nuclear reactors are one of the most intense, pure, controllable, cost-effective, and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavors are quantum mechanical mixtures. Over the past several decades reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle $\\theta_{13}$. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.

  8. Neutrino Oscillation Studies with Reactors

    E-Print Network [OSTI]

    Vogel, Petr; Zhang, Chao

    2015-01-01T23:59:59.000Z

    Nuclear reactors are one of the most intense, pure, controllable, cost-effective, and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavors are quantum mechanical mixtures. Over the past several decades reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle $\\theta_{13}$. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.

  9. Progress Update: Reactor Disassembly Grouting

    ScienceCinema (OSTI)

    Cody, Tom

    2012-06-14T23:59:59.000Z

    Grouting the P&R reactors in order to remove these basins as an environmental threat. This will end the Cold War legacy and end the environmental footprint.

  10. Progress Update: Reactor Disassembly Grouting

    SciTech Connect (OSTI)

    Cody, Tom

    2010-01-01T23:59:59.000Z

    Grouting the P&R reactors in order to remove these basins as an environmental threat. This will end the Cold War legacy and end the environmental footprint.

  11. Neutrino oscillation studies with reactors

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Vogel, P. [California Inst. of Technology (CalTech), Pasadena, CA (United States). Kellog Radiation Lab.; Wen, L.J. [Chinese Academy of Sciences (CAS), Beijing (China). Inst. of High Energy Physics (IHEP); Zhang, C. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-04-27T23:59:59.000Z

    Nuclear reactors are one of the most intense, pure, controllable, cost-effective and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavours are quantum mechanical mixtures. Over the past several decades, reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle ?13. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.

  12. Thermonuclear Reflect AB-Reactor

    E-Print Network [OSTI]

    Alexander Bolonkin

    2008-03-26T23:59:59.000Z

    The author offers a new kind of thermonuclear reflect reactor. The remarkable feature of this new reactor is a three net AB reflector, which confines the high temperature plasma. The plasma loses part of its energy when it contacts with the net but this loss can be compensated by an additional permanent plasma heating. When the plasma is rarefied (has a small density), the heat flow to the AB reflector is not large and the temperature in the triple reflector net is lower than 2000 - 3000 K. This offered AB-reactor has significantly less power then the currently contemplated power reactors with magnetic or inertial confinement (hundreds-thousands of kW, not millions of kW). But it is enough for many vehicles and ships and particularly valuable for tunnelers, subs and space apparatus, where air to burn chemical fuel is at a premium or simply not available. The author has made a number of innovations in this reactor, researched its theory, developed methods of computation, made a sample computation of typical project. The main point of preference for the offered reactor is its likely cheapness as a power source. Key words: Micro-thermonuclear reactor, Multi-reflex AB-thermonuclear reactor, Self-magnetic AB-thermonuclear reactor, aerospace thermonuclear engine.

  13. Analysis of a direct energy conversion system using medium energy helium ions

    E-Print Network [OSTI]

    Carter, Jesse James

    2006-08-16T23:59:59.000Z

    A scaled direct energy conversion device was built to convert kinetic energy of singly ionized helium ions into an electric potential by the process of direct conversion. The experiments in this paper aimed to achieve higher potentials and higher...

  14. Helium and lead isotope geochemistry of oceanic volcanic rocks from the East Pacific and South Atlantic

    E-Print Network [OSTI]

    Graham, David W. (David William)

    1987-01-01T23:59:59.000Z

    The isotopic evolution of helium and lead in the Earth is coupled by virtue of their common radioactive parents uranium and thorium. The isotopic signatures in oceanic volcanic rocks provide constraints on the temporal ...

  15. THERMAL PERFORMANCE OF A DUAL-CHANNEL, HELIUM-COOLED, TUNGSTEN HEAT EXCHANGER

    E-Print Network [OSTI]

    California at Los Angeles, University of

    high heat fluxes. The high temperature helium can then be used to power a gas turbine for high the high efficiency power conversion available from new generation gas turbines. It is envisioned

  16. axial-flow helium gas: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    per atom (dpa) and helium production levels as a function of position within the high flux regions of a recent conceptual model for the "next-step" fusion device DEMO....

  17. A Concept for A Dark Matter Detector Using Liquid Helium-4

    E-Print Network [OSTI]

    Wei Guo; Daniel N. McKinsey

    2013-02-19T23:59:59.000Z

    Direct searches for light dark matter particles (mass $Helium-4 as a target material, taking advantage of the favorable kinematic matching of the Helium nucleus to light dark matter particles. Monte Carlo simulations are performed to calculate the charge, scintillation, and triplet helium molecule signals produced by recoil He ions, for a variety of energies and electric fields. We show that excellent background rejection can be achieved based on the ratios between different signal channels. We also present some concepts for a liquid-helium-based dark matter detector. Key to the proposed approach is the use of a large electric field to extract electrons from the event site, and the amplification of this charge signal, through proportional scintillation, liquid electroluminescence, or roton emission. The sensitivity of the proposed detector to light dark matter particles is estimated for various electric fields and light collection efficiencies.

  18. Helium diffusion during the evolution of solar-type stars : asteroseismic tests

    E-Print Network [OSTI]

    M. Castro; S. Vauclair

    2005-10-20T23:59:59.000Z

    The element diffusion, described by Michaud (1970), is now recognized to occur in all kinds of stars. We attempt to give evidence of signatures of helium diffusion below the convective zone by the way of asteroseismology.

  19. A note on the ultracold neutrons production by neutron deceleration on clusters in liquid helium

    E-Print Network [OSTI]

    Yu. N. Pokotilovski

    2008-12-04T23:59:59.000Z

    An evaluation of slow neutrons deceleration through their interaction with nanoclusters in liquid helium is performed. It is shown that process is strongly suppresed if the clusters are bound by the van der Waals interaction.

  20. Nanostructuring of molybdenum and tungsten surfaces by low-energy helium ions

    SciTech Connect (OSTI)

    De Temmerman, Gregory; Bystrov, Kirill; Zielinski, Jakub J.; Balden, Martin; Matern, Gabriele; Arnas, Cecile; Marot, Laurent [FOM Institute DIFFER, Ducth Institute For Fundamental Energy Research, Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, 3430 BE Nieuwegein (Netherlands); Max Planck Institute for Plasma Physics, EURATOM Association, 85748 Garching (Germany); Laboratoire PIIM, CNRS/Aix-Marseille Universit, 13397 Marseille (France); Department of Physics, University of Basel, Basel, CH-4056 (Switzerland)

    2012-07-15T23:59:59.000Z

    The formation of metallic nanostructures by exposure of molybdenum and tungsten surfaces to high fluxes of low energy helium ions is studied as a function of the ion energy, plasma exposure time, and surface temperature. Helium plasma exposure leads to the formation of nanoscopic filaments on the surface of both metals. The size of the helium-induced nanostructure increases with increasing surface temperature while the thickness of the modified layer increases with time. In addition, the growth rate of the nanostructured layer also depends on the surface temperature. The size of the nanostructure appears linked with the size of the near-surface voids induced by the low energy ions. The results presented here thus demonstrate that surface processing by low-energy helium ions provides an efficient route for the formation of porous metallic nanostructures.

  1. Helium release rates and ODH calculations from RHIC magnet cooling line failure

    SciTech Connect (OSTI)

    Liaw, C.J.; Than, Y.; Tuozzolo, J.

    2011-03-28T23:59:59.000Z

    A catastrophic failure of the magnet cooling lines, similar to the LHC superconducting bus failure incident, could discharge cold helium into the RHIC tunnel and cause an Oxygen Deficiency Hazard (ODH) problem. A SINDA/FLUINT{reg_sign} model, which simulated the 4.5K/4 atm helium flowing through the magnet cooling system distribution lines, then through a line break into the insulating vacuum volumes and discharging via the reliefs into the RHIC tunnel, had been developed. Arc flash energy deposition and heat load from the ambient temperature cryostat surfaces are included in the simulations. Three typical areas: the sextant arc, the Triplet/DX/D0 magnets, and the injection area, had been analyzed. Results, including helium discharge rates, helium inventory loss, and the resulting oxygen concentration in the RHIC tunnel area, are reported. Good agreement had been achieved when comparing the simulation results, a RHIC sector depressurization test measurement, and some simple analytical calculations.

  2. Analysis of a direct energy conversion system using medium energy helium ions 

    E-Print Network [OSTI]

    Carter, Jesse James

    2006-08-16T23:59:59.000Z

    A scaled direct energy conversion device was built to convert kinetic energy of singly ionized helium ions into an electric potential by the process of direct conversion. The experiments in this paper aimed to achieve ...

  3. Reactor coolant pump flywheel

    DOE Patents [OSTI]

    Finegan, John Raymond; Kreke, Francis Joseph; Casamassa, John Joseph

    2013-11-26T23:59:59.000Z

    A flywheel for a pump, and in particular a flywheel having a number of high density segments for use in a nuclear reactor coolant pump. The flywheel includes an inner member and an outer member. A number of high density segments are provided between the inner and outer members. The high density segments may be formed from a tungsten based alloy. A preselected gap is provided between each of the number of high density segments. The gap accommodates thermal expansion of each of the number of segments and resists the hoop stress effect/keystoning of the segments.

  4. Reactor refueling containment system

    DOE Patents [OSTI]

    Gillett, J.E.; Meuschke, R.E.

    1995-05-02T23:59:59.000Z

    A method of refueling a nuclear reactor is disclosed whereby the drive mechanism is disengaged and removed by activating a jacking mechanism that raises the closure head. The area between the barrier plate and closure head is exhausted through the closure head penetrations. The closure head, upper drive mechanism, and bellows seal are lifted away and transported to a safe area. The barrier plate acts as the primary boundary and each drive and control rod penetration has an elastomer seal preventing excessive tritium gases from escaping. The individual instrumentation plugs are disengaged allowing the corresponding fuel assembly to be sealed and replaced. 2 figs.

  5. Nuclear reactor control assembly

    SciTech Connect (OSTI)

    Negron, S.B.

    1991-06-11T23:59:59.000Z

    This patent describes an assembly for providing global power control in a nuclear reactor having the core split into two halves. It comprises a disk assembly formed from at least two disks each machined with an identical surface hole pattern such that rotation of one disk relative to the other causes the hole pattern to open or close, the disk assembly being positioned substantially at the longitudinal center of and coaxial with the core halves; and means for rotating at least one of the disks relative to the other.

  6. Nuclear reactor control apparatus

    SciTech Connect (OSTI)

    Sridhar, B.N.

    1981-08-28T23:59:59.000Z

    Nuclear reactor core safety rod release apparatus comprises a control rod having a detent notch in the form of an annular peripheral recess at its upper end, a control rod support tube for raising and lowering the control rod under normal conditions, latches pivotally mounted on the control support tube with free ends thereof normally disposed in the recess in the control rod, and cam means for pivoting the latches out of the recess in the control rod when a scram condition occurs. One embodiment of the invention comprises an additonal magnetically-operated latch for releasing the control rod under two different conditions, one involving seismic shock.

  7. Biparticle fluidized bed reactor

    DOE Patents [OSTI]

    Scott, C.D.; Marasco, J.A.

    1996-02-27T23:59:59.000Z

    A fluidized bed reactor system is described which utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary and tertiary particulate phases, continuously introduced and removed simultaneously in the cocurrent and countercurrent mode, act in a role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Means for introducing and removing the sorbent phases include feed screw mechanisms and multivane slurry valves. 3 figs.

  8. Biparticle fluidized bed reactor

    DOE Patents [OSTI]

    Scott, Charles D. (Oak Ridge, TN)

    1993-01-01T23:59:59.000Z

    A fluidized bed reactor system which utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary particulate phase, continuously introduced and removed in either cocurrent or countercurrent mode, acts in a secondary role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Introduction and removal of the sorbent phase is accomplished through the use of feed screw mechanisms and multivane slurry valves.

  9. Biparticle fluidized bed reactor

    DOE Patents [OSTI]

    Scott, Charles D. (Oak Ridge, TN); Marasco, Joseph A. (Kingston, TN)

    1995-01-01T23:59:59.000Z

    A fluidized bed reactor system utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary particulate phase, continuously introduced and removed in either cocurrent or countercurrent mode, acts in a secondary role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Introduction and removal of the sorbent phase is accomplished through the use of feed screw mechanisms and multivane slurry valves.

  10. Biparticle fluidized bed reactor

    DOE Patents [OSTI]

    Scott, Charles D. (Oak Ridge, TN); Marasco, Joseph A. (Kingston, TN)

    1996-01-01T23:59:59.000Z

    A fluidized bed reactor system which utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary and tertiary particulate phases, continuously introduced and removed simultaneously in the cocurrent and countercurrent mode, act in a role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Means for introducing and removing the sorbent phases include feed screw mechanisms and multivane slurry valves.

  11. Biparticle fluidized bed reactor

    DOE Patents [OSTI]

    Scott, C.D.

    1993-12-14T23:59:59.000Z

    A fluidized bed reactor system which utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase is described. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary particulate phase, continuously introduced and removed in either cocurrent or countercurrent mode, acts in a secondary role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Introduction and removal of the sorbent phase is accomplished through the use of feed screw mechanisms and multivane slurry valves. 3 figures.

  12. Reactor refueling containment system

    DOE Patents [OSTI]

    Gillett, James E. (Greensburg, PA); Meuschke, Robert E. (Pittsburgh, PA)

    1995-01-01T23:59:59.000Z

    A method of refueling a nuclear reactor whereby the drive mechanism is disengaged and removed by activating a jacking mechanism that raises the closure head. The area between the barrier plate and closure head is exhausted through the closure head penetrations. The closure head, upper drive mechanism, and bellows seal are lifted away and transported to a safe area. The barrier plate acts as the primary boundary and each drive and control rod penetration has an elastomer seal preventing excessive tritium gases from escaping. The individual instrumentation plugs are disengaged allowing the corresponding fuel assembly to be sealed and replaced.

  13. Biparticle fluidized bed reactor

    DOE Patents [OSTI]

    Scott, C.D.; Marasco, J.A.

    1995-04-25T23:59:59.000Z

    A fluidized bed reactor system utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary particulate phase, continuously introduced and removed in either cocurrent or countercurrent mode, acts in a secondary role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Introduction and removal of the sorbent phase is accomplished through the use of feed screw mechanisms and multivane slurry valves. 3 figs.

  14. Nuclear reactor control apparatus

    DOE Patents [OSTI]

    Sridhar, Bettadapur N. (Cupertino, CA)

    1983-11-01T23:59:59.000Z

    Nuclear reactor core safety rod release apparatus comprises a control rod having a detent notch in the form of an annular peripheral recess at its upper end, a control rod support tube for raising and lowering the control rod under normal conditions, latches pivotally mounted on the control support tube with free ends thereof normally disposed in the recess in the control rod, and cam means for pivoting the latches out of the recess in the control rod when a scram condition occurs. One embodiment of the invention comprises an additional magnetically-operated latch for releasing the control rod under two different conditions, one involving seismic shock.

  15. N Reactor - Hanford Site

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your1 SECTIONES2008-54174MoreMuseum Day atMyNERSCVanN Reactor

  16. Fast Reactor Fuel Type and Reactor Safety Performance

    SciTech Connect (OSTI)

    R. Wigeland; J. Cahalan

    2009-09-01T23:59:59.000Z

    Fast Reactor Fuel Type and Reactor Safety Performance R. Wigeland , Idaho National Laboratory J. Cahalan, Argonne National Laboratory The sodium-cooled fast neutron reactor is currently being evaluated for the efficient transmutation of the highly-hazardous, long-lived, transuranic elements that are present in spent nuclear fuel. One of the fundamental choices that will be made is the selection of the fuel type for the fast reactor, whether oxide, metal, carbide, nitride, etc. It is likely that a decision on the fuel type will need to be made before many of the related technologies and facilities can be selected, from fuel fabrication to spent fuel reprocessing. A decision on fuel type should consider all impacts on the fast reactor system, including safety. Past work has demonstrated that the choice of fuel type may have a significant impact on the severity of consequences arising from accidents, especially for severe accidents of low probability. In this paper, the response of sodium-cooled fast reactors is discussed for both oxide and metal fuel types, highlighting the similarities and differences in reactor response and accident consequences. Any fast reactor facility must be designed to be able to successfully prevent, mitigate, or accommodate all consequences of potential events, including accidents. This is typically accomplished by using multiple barriers to the release of radiation, including the cladding on the fuel, the intact primary cooling system, and most visibly the reactor containment building. More recently, this has also included the use of ‘inherent safety’ concepts to reduce or eliminate the potential for serious damage in some cases. Past experience with oxide and metal fuel has demonstrated that both fuel types are suitable for use as fuel in a sodium-cooled fast reactor. However, safety analyses for these two fuel types have also shown that there can be substantial differences in accident consequences due to the neutronic and thermophysical properties of the fuel and their compatibility with the reactor coolant, with corresponding differences in the challenges presented to the reactor developers. Accident phenomena are discussed for the sodium-cooled fast reactor based on the mechanistic progression of conditions from accident initiation to accident termination, whether a benign state is achieved or more severe consequences are expected. General principles connecting accident phenomena and fuel properties are developed from the oxide and metal fuel safety analyses, providing guidelines that can be used as part of the evaluation for selection of fuel type for the sodium-cooled fast reactor.

  17. An apparatus to measure fourth sound interactions with helium II in rotation 

    E-Print Network [OSTI]

    Burrin, Stephen Eller

    1968-01-01T23:59:59.000Z

    . Sound Cavity and Transducers Figure 7. Basic Diagram of Transducer Electronics 12 14 17 19 22 CHAPTER I IKTRODUCTIOiV Although H. Ksmerlingh Onnes liquefied helium gas, which con- sists almost completely of the isotope He, in 1908... Regulator Ballast Tank Higg Capacity Vacuum Pump Large Vacuum Line to Reduce Impedance Large Valve Roughing Pump Hitrogcn Deuar . '-'. annmctet Helium Dcmar RICURU 4 HRLIUH HURRI"?'( SYSTPH 15 atmospheric pressure) could be obtained...

  18. A Conceptual Multi-Megawatt System Based on a Tungsten CERMET Reactor

    SciTech Connect (OSTI)

    Jonathan A. Webb; Brian Gross

    2011-02-01T23:59:59.000Z

    Abstract. A conceptual reactor system to support Multi-Megawatt Nuclear Electric Propulsion is investigated within this paper. The reactor system consists of a helium cooled Tungsten-UN fission core, surrounded by a beryllium neutron reflector and 13 B4C control drums coupled to a high temperature Brayton power conversion system. Excess heat is rejected via carbon reinforced heat pipe radiators and the gamma and neutron flux is attenuated via segmented shielding consisting of lithium hydride and tungsten layers. Turbine inlet temperatures ranging from 1300 K to 1500 K are investigated for their effects on specific powers and net electrical outputs ranging from 1 MW to 100 MW. The reactor system is estimated to have a mass, which ranges from 15 Mt at 1 MWe and a turbine inlet temperature of 1500 K to 1200 Mt at 100 MWe and a turbine temperature of 1300 K. The reactor systems specific mass ranges from 32 kg/kWe at a turbine inlet temperature of 1300 K and a power of 1 MWe to 9.5 kg/kW at a turbine temperature of 1500 K and a power of 100 MWe.

  19. Granular Dynamics in Pebble Bed Reactor Cores

    E-Print Network [OSTI]

    Laufer, Michael Robert

    2013-01-01T23:59:59.000Z

    in a pebble-bed nuclear reactor,” Phys. Rev. E, vol. 74, no.cycles of the pebble bed reactor,” Nuclear Engineering andoptimization of pebble-bed reactors,” Annals of Nuclear

  20. Slow isocharged sequence ions with helium collisions: Projectile core dependence

    SciTech Connect (OSTI)

    Yu Deyang; Cai Xiaohong; Shao Caojie; Lu Jun; Yang Zhihu [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Lu Rongchun; Ruan Fangfang [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Zhang Hongqiang; Cui Ying; Xu Xu; Shao Jianxiong; Ding Baowei; Chen Ximeng; Liu Zhaoyuan [Department of Modern Physics, Lanzhou University, Lanzhou 730000 (China)

    2007-08-15T23:59:59.000Z

    The collisions of the isocharged sequence ions of q=6 (C{sup 6+}, N{sup 6+}, O{sup 6+}, F{sup 6+}, Ne{sup 6+}, Ar{sup 6+}, and Ca{sup 6+}), q=7 (F{sup 7+}, Ne{sup 7+}, S{sup 7+}, Ar{sup 7+}, and Ca{sup 7+}), q=8 (F{sup 8+}, Ne{sup 8+}, Ar{sup 8+}, and Ca{sup 8+}), q=9 (F{sup 9+}, Ne{sup 9+}, Si{sup 9+}, S{sup 9+}, Ar{sup 9+}, and Ca{sup 9+}) and q=11 (Si{sup 11+}, Ar{sup 11+}, and Ca{sup 11+}) with helium at the same velocities were investigated. The cross-section ratios of the double-electron transfer (DET) to the single-electron capture (SEC) {sigma}{sup DET}/{sigma}{sup SEC} and the true double-electron capture (TDC) to the double-electron transfer {sigma}{sup TDC}/{sigma}{sup DET} were measured. It shows that for different ions in an isocharged sequence, the experimental cross-section ratio {sigma}{sup DET}/{sigma}{sup SEC} varies by a factor of 3. The results confirm that the projectile core is another dominant factor besides the charge state and the collision velocity in slow (0.35-0.49v{sub 0}; v{sub 0} denotes the Bohr velocity) highly charged ions (HCIs) with helium collisions. The experimental cross-section ratio {sigma}{sup DET}/{sigma}{sup SEC} is compared with the extended classical over-barrier model (ECBM) [A. Barany et al., Nucl. Instrum. Methods Phys. Res. B 9, 397 (1985)], the molecular Coulombic barrier model (MCBM) [A. Niehaus, J. Phys. B 19, 2925 (1986)], and the semiempirical scaling laws (SSL) [N. Selberg et al., Phys. Rev. A 54, 4127 (1996)]. It also shows that the projectile core properties affect the initial capture probabilities as well as the subsequent relaxation of the projectiles. The experimental cross-section ratio {sigma}{sup TDC}/{sigma}{sup DET} for those lower isocharged sequences is dramatically affected by the projectile core structure, while for those sufficiently highly isocharged sequences, the autoionization always dominates, hence the cross-section ratio {sigma}{sup TDC}/{sigma}{sup DET} is always small.

  1. CONDITIONS FOR SUCCESSFUL HELIUM DETONATIONS IN ASTROPHYSICAL ENVIRONMENTS

    SciTech Connect (OSTI)

    Holcomb, Cole; Guillochon, James; De Colle, Fabio; Ramirez-Ruiz, Enrico [TASC, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

    2013-07-01T23:59:59.000Z

    Several models for Type Ia-like supernova events rely on the production of a self-sustained detonation powered by nuclear reactions. In the absence of hydrogen, the fuel that powers these detonations typically consists of either pure helium (He) or a mixture of carbon and oxygen (C/O). Studies that systematically determine the conditions required to initiate detonations in C/O material exist, but until now no analogous investigation of He matter has been conducted. We perform one-dimensional reactive hydrodynamical simulations at a variety of initial density and temperature combinations and find critical length scales for the initiation of He detonations that range between 1 and 10{sup 10} cm. A simple estimate of the length scales over which the total consumption of fuel will occur for steady-state detonations is provided by the Chapman-Jouguet (CJ) formalism. Our initiation lengths are consistently smaller than the corresponding CJ length scales by a factor of {approx}100, providing opportunities for thermonuclear explosions in a wider range of low-mass white dwarfs (WDs) than previously thought possible. We find that virialized WDs with as little mass as 0.24 M{sub Sun} can be detonated, and that even less massive WDs can be detonated if a sizable fraction of their mass is raised to a higher adiabat. That the initiation length is exceeded by the CJ length implies that certain systems may not reach nuclear statistical equilibrium within the time it takes a detonation to traverse the object. In support of this hypothesis, we demonstrate that incomplete burning will occur in the majority of He WD detonations and that {sup 40}Ca, {sup 44}Ti, or {sup 48}Cr, rather than {sup 56}Ni, is the predominant burning product for many of these events. We anticipate that a measure of the quantity of the intermediate-mass elements and {sup 56}Ni produced in a helium-rich thermonuclear explosion can potentially be used to constrain the nature of the progenitor system.

  2. THE GREEN BANK TELESCOPE H II REGION DISCOVERY SURVEY. IV. HELIUM AND CARBON RECOMBINATION LINES

    SciTech Connect (OSTI)

    Wenger, Trey V.; Bania, T. M. [Astronomy Department, 725 Commonwealth Avenue, Boston University, Boston, MA 02215 (United States)] [Astronomy Department, 725 Commonwealth Avenue, Boston University, Boston, MA 02215 (United States); Balser, Dana S. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA, 22903-2475 (United States)] [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA, 22903-2475 (United States); Anderson, L. D. [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States)] [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States)

    2013-02-10T23:59:59.000Z

    The Green Bank Telescope H II Region Discovery Survey (GBT HRDS) found hundreds of previously unknown Galactic regions of massive star formation by detecting hydrogen radio recombination line (RRL) emission from candidate H II region targets. Since the HRDS nebulae lie at large distances from the Sun, they are located in previously unprobed zones of the Galactic disk. Here, we derive the properties of helium and carbon RRL emission from HRDS nebulae. Our target sample is the subset of the HRDS that has visible helium or carbon RRLs. This criterion gives a total of 84 velocity components (14% of the HRDS) with helium emission and 52 (9%) with carbon emission. For our highest quality sources, the average {sup 4}He{sup +}/H{sup +} abundance ratio by number, (y {sup +}), is 0.068 {+-} 0.023(1{sigma}). This is the same ratio as that measured for the sample of previously known Galactic H II regions. Nebulae without detected helium emission give robust y {sup +} upper limits. There are 5 RRL emission components with y {sup +} less than 0.04 and another 12 with upper limits below this value. These H II regions must have either a very low {sup 4}He abundance or contain a significant amount of neutral helium. The HRDS has 20 nebulae with carbon RRL emission but no helium emission at its sensitivity level. There is no correlation between the carbon RRL parameters and the 8 {mu}m mid-infrared morphology of these nebulae.

  3. Modeling the pressure increase in liquid helium cryostats after failure of the insulating vacuum

    SciTech Connect (OSTI)

    Heidt, C.; Grohmann, S. [Karlsruhe Institute of Technology, Institute for Technical Physics, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany and Karlsruhe Institute of Technology, Institute for Technical Thermodynamics and Refrigeration, Engler-Bunte (Germany); Süßer, M. [Karlsruhe Institute of Technology, Institute for Technical Physics, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)

    2014-01-29T23:59:59.000Z

    The pressure relief system of liquid helium cryostats requires a careful design, due to helium's low enthalpy of vaporization and due to the low operating temperature. Hazard analyses often involve the failure of the insulating vacuum in the worst-case scenario. The venting of the insulating vacuum and the implications for the pressure increase in the helium vessel, however, have not yet been fully analyzed. Therefore, the dimensioning of safety devices often requires experience and reference to very few experimental data. In order to provide a better foundation for the design of cryogenic pressure relief systems, this paper presents an analytic approach for the strongly dynamic process induced by the loss of insulating vacuum. The model is based on theoretical considerations and on differential equation modeling. It contains only few simplifying assumptions, which will be further investigated in future experiments. The numerical solutions of example calculations are presented with regard to the heat flux into the helium vessel, the helium pressure increase and the helium flow rate through the pressure relief device. Implications concerning two-phase flow and the influence of kinetic energy are discussed.

  4. AM Canum Venaticorum Progenitors with Helium Star Donors and the resultant Explosions

    E-Print Network [OSTI]

    Brooks, Jared; Marchant, Pablo; Paxton, Bill

    2015-01-01T23:59:59.000Z

    We explore the outcome of mass transfer via Roche lobe overflow (RLOF) of $M_{\\rm He}\\lesssim0.51 M_\\odot$ pure helium burning stars in close binaries with white dwarfs (WDs). The evolution is driven by the loss of angular momentum through gravitational wave radiation (GWR), and both stars are modeled using Modules for Experiments in Stellar Astrophysics (MESA). The donors have masses of $M_{\\rm He}=0.35, 0.4, \\&\\ 0.51M_\\odot$ and accrete onto WDs of mass $M_{\\rm WD}$ from $0.6M_\\odot$ to $1.26M_\\odot$. The initial orbital periods ($P_{\\rm{orb}}$) span 20 to 80 minutes. For all cases, the accretion rate onto the WD is below the stable helium burning range, leading to accumulation of helium followed by unstable ignition. The mass of the convective core in the donors is small enough so that the WD accretes enough helium-rich matter to undergo a thermonuclear runaway in the helium shell before any carbon-oxygen enriched matter is transferred. The mass of the accumulated helium shell depends on $M_{\\rm WD}$ a...

  5. Gaseous reactor control system

    SciTech Connect (OSTI)

    Abdel-Khalik, S.

    1991-09-03T23:59:59.000Z

    This paper describes a nuclear reactor control system for controlling the reactivity of the core of a nuclear reactor. It includes a control gas having a high neutron cross-section; a first tank containing a first supply of the control gas; a first conduit providing a first fluid passage extending into the core, the first conduit being operatively connected to communicate with the first tank; a first valve operatively connected to regulate the flow of the control gas between the first tank and the first conduit; a second conduit concentrically disposed around the first conduit such that a second fluid passage is defined between the outer surface of the first conduit and the inner surface of the second conduit; a second tank containing a second supply of the control gas, the second tank being operatively connected to communicate with the second fluid passage; a second supply valve operatively connected to regulate the flow of the control gas between the second tank and the second fluid passage.

  6. Solvent refined coal reactor quench system

    DOE Patents [OSTI]

    Thorogood, R.M.

    1983-11-08T23:59:59.000Z

    There is described an improved SRC reactor quench system using a condensed product which is recycled to the reactor and provides cooling by evaporation. In the process, the second and subsequent reactors of a series of reactors are cooled by the addition of a light oil fraction which provides cooling by evaporation in the reactor. The vaporized quench liquid is recondensed from the reactor outlet vapor stream. 1 fig.

  7. Design modification for the modular helium reactor for higher temperature operation and reliability studies for nuclear hydrogen production processes 

    E-Print Network [OSTI]

    Reza, S.M. Mohsin

    2009-05-15T23:59:59.000Z

    of graphite removed from the PSR to create this inlet path. With the removal of ~10% of the graphite from PSR the PVT is reduced from 541 0C to 421 0C. A new design for the graphite block core has been evaluated and optimized to reduce the inlet coolant...

  8. Reactor Neutrino Physics -- An Update

    E-Print Network [OSTI]

    Felix Boehm

    1999-06-18T23:59:59.000Z

    We review the status and the results of reactor neutrino experiments. Long baseline oscillation experiments at Palo Verde and Chooz have provided limits for the oscillation parameters while the recently proposed Kamland experiment at a baseline of more than 100km is now in the planning stage. We also describe the status of neutrino magnetic moment experiments at reactors.

  9. Radiation Shielding for Fusion Reactors

    SciTech Connect (OSTI)

    Santoro, R.T.

    1999-10-01T23:59:59.000Z

    Radiation shielding requirements for fusion reactors present different problems than those for fission reactors and accelerators. Fusion devices, particularly tokamak reactors, are complicated by geometry constraints that complicate disposition of fully effective shielding. This paper reviews some of these shielding issues and suggested solutions for optimizing the machine and biological shielding. Radiation transport calculations are essential for predicting and confirming the nuclear performance of the reactor and, as such, must be an essential part of the reactor design process. Development and optimization of reactor components from the first wall and primary shielding to the penetrations and containment shielding must be carried out in a sensible progression. Initial results from one-dimensional transport calculations are used for scoping studies and are followed by detailed two- and three-dimensional analyses to effectively characterize the overall radiation environment. These detail model calculations are essential for accounting for the radiation leakage through ports and other penetrations in the bulk shield. Careful analysis of component activation and radiation damage is cardinal for defining remote handling requirements, in-situ replacement of components, and personnel access at specific locations inside the reactor containment vessel. Radiation shielding requirements for fusion reactors present different problems than those for fission reactors and accelerators. Fusion devices, particularly tokamak reactors, are complicated by geometry constraints that complicate disposition of fully effective shielding. This paper reviews some of these shielding issues and suggested solutions for optimizing the machine and biological shielding. Radiation transport calculations are essential for predicting and confirming the nuclear performance of the reactor and, as such, must be an essential part of the reactor design process. Development and optimization of reactor components from the first wall and primary shielding to the penetrations and containment shielding must be carried out in a sensible progression. Initial results from one-dimensional transport calculations are used for scoping studies and are followed by detailed two- and three-dimensional analyses to effectively characterize the overall radiation environment. These detail model calculations are essential for accounting for the radiation leakage through ports and other penetrations in the bulk shield. Careful analysis of component activation and radiation damage is cardinal for defining remote handling requirements, in-situ replacement of components, and personnel access at specific locations inside the reactor containment vessel.

  10. Granular Dynamics in Pebble Bed Reactor Cores

    E-Print Network [OSTI]

    Laufer, Michael Robert

    2013-01-01T23:59:59.000Z

    gas reactors with the effective heat transfer of a molten salt coolant and the passive natural circulation safety systems of sodium fast reactors.

  11. MOOSE simulating nuclear reactor CRUD buildup

    ScienceCinema (OSTI)

    None

    2014-07-21T23:59:59.000Z

    This simulation uses multiple physical models to show how the buildup of boron deposits on reactor fuel can affect performance and the reactor's power profile.

  12. MOOSE simulating nuclear reactor CRUD buildup

    SciTech Connect (OSTI)

    None

    2014-02-06T23:59:59.000Z

    This simulation uses multiple physical models to show how the buildup of boron deposits on reactor fuel can affect performance and the reactor's power profile.

  13. The Endurance Bioenergy Reactor | Argonne National Laboratory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    The Endurance Bioenergy Reactor Share Description Argonne biophysicist Dr. Philip Laible and Air Force Major Matt Michaud talks about he endurance bioenergy reactor-a device that...

  14. Fast reactors and nuclear nonproliferation

    SciTech Connect (OSTI)

    Avrorin, E.N. [Russian Federal Nuclear Center - Zababakhin Institute of Applied Physics, Snezhinsk (Russian Federation); Rachkov, V.I.; Chebeskov, A.N. [State Scientific Center of the Russian Federation - Institute for Physics and Power Engineering, Bondarenko Square, 1, Obninsk, Kaluga region, 249033 (Russian Federation)

    2013-07-01T23:59:59.000Z

    Problems are discussed with regard to nuclear fuel cycle resistance in fast reactors to nuclear proliferation risk due to the potential for use in military programs of the knowledge, technologies and materials gained from peaceful nuclear power applications. Advantages are addressed for fast reactors in the creation of a more reliable mode of nonproliferation in the closed nuclear fuel cycle in comparison with the existing fully open and partially closed fuel cycles of thermal reactors. Advantages and shortcomings are also discussed from the point of view of nonproliferation from the start with fast reactors using plutonium of thermal reactor spent fuel and enriched uranium fuel to the gradual transition using their own plutonium as fuel. (authors)

  15. Advanced gas cooled nuclear reactor materials evaluation and development program. Progress report, October 1, 1979-December 31, 1979

    SciTech Connect (OSTI)

    Not Available

    1980-04-18T23:59:59.000Z

    This report presents the results of work performed from October 1, 1979 through December 31, 1979. Work covered in this report includes the activities associated with the status of the simulated reactor helium supply system, testing equipment and gas chemistry analysis instrumentation and equipment. The progress in the screening test program is described. This includes: screening creep results, weight gain and post-exposure mechanical properties for materials thermally exposed at 750/sup 0/ and 850/sup 0/C (1382/sup 0/ and 1562/sup 0/F). In addition, the status of the data management system is described.

  16. Fission Product Impact Reduction via Protracted In-core Retention in Very High Temperature Reactor (VHTR) Transmutation Scenarios 

    E-Print Network [OSTI]

    Alajo, Ayodeji Babatunde

    2011-08-08T23:59:59.000Z

    of HTGR by improvements in thermal efficiency and deployment for high-temperature applications such as hydrogen production, sea-water desalination and industrial process heat supply [17]. The VHTR is a graphite-moderated helium-cooled reactor...-based transmutation concept takes advantage of the higher number of steps it takes for a neutron to slow-down to thermal energies in graphite than the steps required in conventional LWR. The reduced slowing-down rate in graphite media favors the attainment...

  17. The primordial Helium-4 abundance determination: systematic effects

    E-Print Network [OSTI]

    T. X. Thuan; Y. I. Izotov

    2001-12-14T23:59:59.000Z

    By extrapolating to O/H = N/H = 0 the empirical correlations Y-O/H and Y-N/H defined by a relatively large sample of ~ 45 Blue Compact Dwarfs (BCDs), we have obtained a primordial 4Helium mass fraction Yp= 0.2443+/-0.0015 with dY/dZ = 2.4+/-1.0. This result is in excellent agreement with the average Yp= 0.2452+/-0.0015 determined in the two most metal-deficient BCDs known, I Zw 18 (Zsun/50) and SBS 0335-052 (Zsun/41), where the correction for He production is smallest. The quoted error (1sigma) of < 1% is statistical and does not include systematic effects. We examine various systematic effects including collisional excitation of Hydrogen lines, ionization structure and temperature fluctuation effects, and underlying stellar HeI absorption, and conclude that combining all systematic effects, our Yp may be underestimated by ~ 2-4%. Taken at face value, our Yp implies a baryon-to-photon number ratio eta = 4.7x10^-10 and a baryon mass fraction Omega_b h^2_{100} = 0.017+/-0.005 (2sigma), consistent with the values obtained from deuterium and Cosmic Microwave Background measurements. Correcting Yp upward by 2-4% would make the agreement even better.

  18. Helium/solid powder O-ring leakage correlation experiments

    SciTech Connect (OSTI)

    Leisher, W.B.; Weissman, S.H.; Tallant, D.R.; Kubo, M.

    1983-01-01T23:59:59.000Z

    We have developed a method to test powder leakage that has passed O-ring seals. To validate this method we have spiked a test fixture with 98 ng of U and recovered 130 +- 25 ng of U. We did not detect U at a detection limit of 26 ng in a fixture which was treated as a blank. This method has been applied to the leakage of UO/sub 2/ powder passing the type of EPDM O-ring seals used in a SNM shipping cask belonging to PNC. Considering the three experimental tests in which no or very small quantities of U were detected as effective blank test, it appears that the level of external contamination is negligible. Therefore, we believe that the U quantities greater than 26 ng (6 tests) passed the primary O-ring seal. From this limited quantity of data, we observe no apparent correlation between the amount of U measured and either helium leak rate or equivalent tube diameter. The data for the 130/sup 0/C tests indicate the possibility of a U/time relationship; however, more data are needed for verification.

  19. Communication: Helium nanodroplet isolation and rovibrational spectroscopy of hydroxymethylene

    SciTech Connect (OSTI)

    Leavitt, Christopher M.; Moradi, Christopher P.; Douberly, Gary E., E-mail: douberly@uga.edu [Department of Chemistry, University of Georgia, Athens, Georgia 30602 (United States); Stanton, John F. [Institute for Theoretical Chemistry, Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712 (United States)] [Institute for Theoretical Chemistry, Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712 (United States)

    2014-05-07T23:59:59.000Z

    Hydroxymethylene (HCOH) and its d{sub 1}-isotopologue (HCOD) are isolated in low temperature helium nanodroplets following pyrolysis of glyoxylic acid. Transitions identified in the infrared spectrum are assigned exclusively to the trans-conformation based on previously reported anharmonic frequency computations [P. R. Schreiner, H. P. Reisenauer, F. C. Pickard, A. C. Simmonett, W. D. Allen, E. Mátyus, and A. G. Császár, Nature 453, 906 (2008); L. Koziol, Y. M. Wang, B. J. Braams, J. M. Bowman, and A. I. Krylov, J. Chem. Phys. 128, 204310 (2008)]. For the OH(D) and CH stretches, a- and b-type transitions are observed, and when taken in conjunction with CCSD(T)/cc-pVTZ computations, lower limits to the vibrational band origins are determined. The relative intensities of the a- and b-type transitions provide the orientation of the transition dipole moment in the inertial frame. The He nanodroplet data are in excellent agreement with anharmonic frequency computations reported here and elsewhere, confirming an appreciable Ar-matrix shift of the OH and OD stretches and strong anharmonic resonance interactions in the high-frequency stretch regions of the mid-infrared.

  20. Oscillatory superfluid Ekman pumping in Helium II and neutron stars

    E-Print Network [OSTI]

    van Eysden, C Anthony

    2015-01-01T23:59:59.000Z

    The linear response of a superfluid, rotating uniformly in a cylindrical container and threaded with a large number of vortex lines, to an impulsive increase in the angular velocity of the container is investigated. At zero temperature and with perfect pinning of vortices to the top and bottom of the container, we demonstrate that the system oscillates persistently with a frequency proportional to the vortex line tension parameter to the quarter power. This low-frequency mode is generated by a secondary flow analogous to classical Ekman pumping that is periodically reversed by the vortex tension in the boundary layers. We compare analytic solutions to the two-fluid equations of Chandler & Baym (1986) with the spin-up experiments of Tsakadze & Tsakadze (1980) in helium II and find the frequency agrees within a factor of four, although the experiment is not perfectly suited to the application of the linear theory. We argue that this oscillatory Ekman pumping mode, and not Tkachenko modes provide a natur...

  1. Quantum computing with single electron bubbles in helium

    E-Print Network [OSTI]

    Weijun Yao

    2005-10-27T23:59:59.000Z

    An electron inside liquid helium forms a bubble of 17 \\AA in radius. In an external magnetic field, the two-level system of a spin 1/2 electron is ideal for the implementation of a qubit for quantum computing. The electron spin is well isolated from other thermal reservoirs so that the qubit should have very long coherence time. By confining a chain of single electron bubbles in a linear RF quadrupole trap, a multi-bit quantum register can be implemented. All spins in the register can be initialized to the ground state either by establishing thermal equilibrium at a temperature around 0.1 K and at a magnetic field of 1 T or by sorting the bubbles to be loaded into the trap with magnetic separation. Schemes are designed to address individual spins and to do two-qubit CNOT operations between the neighboring spins. The final readout can be carried out through a measurement similar to the Stern-Gerlach experiment.

  2. Helium Behavior in Oxide Nuclear Fuels: First Principles Modeling

    SciTech Connect (OSTI)

    D. Gryaznov; S. Rashkeev; E. A. Kotomin; E. Heifets; Y. Zhukovskii

    2010-10-01T23:59:59.000Z

    UO2 and (U, Pu)O2 solid solutions (the so-called MOX) nowadays are used as commercial nuclear fuels in many countries. One of the safety issues during the storage of these fuels is related to their self-irradiation that produces and accumulates point defects and helium therein. We present density functional theory (DFT) calculations for UO2, PuO2 and MOX containing He atoms in octahedral interstitial positions. In particular, we calculated basic MOX properties and He incorporation energies as functions of Pu concentration within the spin-polarized, generalized gradient approximation (GGA) DFT calculations. We also included the on-site electron correlation corrections using the Hubbard model (in the framework of the so-called DFT + U approach). We found that PuO2 remains semiconducting with He in the octahedral position while UO2 requires a specific lattice distortion. Both materials reveal a positive energy for He incorporation, which, therefore, is an exothermic process. The He incorporation energy increases with the Pu concentration in the MOX fuel.

  3. Microsoft Word - 12-9155160-000 - Pebble Bed Reactor Assessment...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    core, and internals. * Primary circuit components * Confinement envelope * Decay heat removal * Helium purification system * Fuel handling and storage * Emergency power...

  4. MIT PEBBLE BED REACTOR PROJECT ANDREW C. KADAK

    E-Print Network [OSTI]

    to helium heat exchanger (IHX). The outlet of the IHX is input to a three shaft horizontal Brayton Cycle

  5. Automatic reactor power control for a pressurized water reactor

    SciTech Connect (OSTI)

    Jungin Choi (Kyungwon Univ. (Korea, Republic of)); Yungjoon Hah (Korea Atomic Energy Research Inst., Daejeon (Korea, Republic of)); Unchul Lee (Seoul National Univ. (Korea, Republic of))

    1993-05-01T23:59:59.000Z

    An automatic reactor power control system is presented for a pressurized water reactor (PWR). The associated reactor control strategy is called mode K.' The new system implements a heavy-worth bank dedicated to axial shape control, independent of the existing regulating banks. The heavy bank provides a monotonic relationship between its motion and the axial shape change, which allows automatic control of the axial power distribution. Thus, the mode K enables precise regulation of both the reactivity and the power distribution, by using double closed-loop control of the reactor coolant temperature and the axial power difference. Automatic reactor power control permits the nuclear power plant to accommodate the load-follow operations, including frequency control, to respond to the grid requirements. The mode K reactor control concepts were tested using simulation responses of a Korean standardized 1,000-MW (electric) PWR. The simulation results illustrate that the mode K would be a practical reactor power control strategy for the increased automation of nuclear plants.

  6. Transmutation of high-level radioactive waste and production of {sup 233}U using an accelerator-driven reactor

    SciTech Connect (OSTI)

    Takahashi, Hiroshi; Takashita, Hirofumi; Chen, Xinyi

    1994-08-01T23:59:59.000Z

    Reactor safety, the disposal of high-level nuclear waste, and nonproliferation of nuclear material for military purposes are the problems of greatest concern for nuclear energy. Technologies for accelerators developed in the field of high-energy physics can contribute to solving these problems. For reactor safety, especially for that of a Na-cooled fast reactor, the use of an accelerator, even a small one, can enhance the safety using a slightly subcritical reactor. There is growing concern about how we can deal with weapons-grade Pu, and about the large amount of Pu accumulating from the operation of commercial reactors. It has been suggested that this Pu could be incinerated, using the reactor and a proton accelerator. However, because Pu is a very valuable material with future potential for generating nuclear energy, we should consider transforming it into a proliferation-resistant material that cannot be used for making bombs, rather than simply eliminating the Pu. An accelerator-driven fast reactor (700 MWt), run in a subcritical condition, and fueled with MOX can generate {sup 233}U more safely and efficiently than can a critical reactor. We evaluate the production of {sup 233}U, {sup 239}Pu, and the transmutation of the long-lived fission products of {sup 99}Tc and {sup 129}I, which are loaded with YH{sub 1.7} between the fast core and blanket, by reducing the conversion factor of Pu to {sup 233}U. And we assessed the rates of radiation damage, hydrogen production, and helium production in a target window and in the surrounding vessel.

  7. Nuclear reactor engineering: Reactor design basics. Fourth edition, Volume One

    SciTech Connect (OSTI)

    Glasstone, S.; Sesonske, A.

    1994-12-31T23:59:59.000Z

    This new edition of this classic reference combines broad yet in-depth coverage of nuclear engineering principles with practical descriptions of their application in design and operation of nuclear power plants. Extensively updated, the fourth edition includes new material on reactor safety and risk analysis, regulation, fuel management, waste management, and operational aspects of nuclear power. This volume contains the following: energy from nuclear fission; nuclear reactions and radiations; neutron transport; nuclear design basics; nuclear reactor kinetics and control; radiation protection and shielding; and reactor materials.

  8. University Reactor Conversion Lessons Learned Workshop for Purdue University Reactor

    SciTech Connect (OSTI)

    Eric C. Woolstenhulme; Dana M. Hewit

    2008-09-01T23:59:59.000Z

    The Department of Energy’s Idaho National Laboratory, under its programmatic responsibility for managing the University Research Reactor Conversions, has completed the conversion of the reactor at Purdue University Reactor. With this work completed and in anticipation of other impending conversion projects, the INL convened and engaged the project participants in a structured discussion to capture the lessons learned. The lessons learned process has allowed us to capture gaps, opportunities, and good practices, drawing from the project team’s experiences. These lessons will be used to raise the standard of excellence, effectiveness, and efficiency in all future conversion projects.

  9. Economic Analysis of a Nuclear Reactor Powered High-Temperature Electrolysis Hydrogen Production Plant

    SciTech Connect (OSTI)

    E. A. Harvego; M. G. McKellar; M. S. Sohal; J. E. O'Brien; J. S. Herring

    2008-08-01T23:59:59.000Z

    A reference design for a commercial-scale high-temperature electrolysis (HTE) plant for hydrogen production was developed to provide a basis for comparing the HTE concept with other hydrogen production concepts. The reference plant design is driven by a high-temperature helium-cooled nuclear reactor coupled to a direct Brayton power cycle. The reference design reactor power is 600 MWt, with a primary system pressure of 7.0 MPa, and reactor inlet and outlet fluid temperatures of 540°C and 900°C, respectively. The electrolysis unit used to produce hydrogen includes 4,009,177 cells with a per-cell active area of 225 cm2. The optimized design for the reference hydrogen production plant operates at a system pressure of 5.0 MPa, and utilizes an air-sweep system to remove the excess oxygen that is evolved on the anode (oxygen) side of the electrolyzer. The inlet air for the air-sweep system is compressed to the system operating pressure of 5.0 MPa in a four-stage compressor with intercooling. The alternating-current, AC, to direct-current, DC, conversion efficiency is 96%. The overall system thermal-to-hydrogen production efficiency (based on the lower heating value of the produced hydrogen) is 47.12% at a hydrogen production rate of 2.356 kg/s. An economic analysis of this plant was performed using the standardized H2A Analysis Methodology developed by the Department of Energy (DOE) Hydrogen Program, and using realistic financial and cost estimating assumptions. The results of the economic analysis demonstrated that the HTE hydrogen production plant driven by a high-temperature helium-cooled nuclear power plant can deliver hydrogen at a competitive cost. A cost of $3.23/kg of hydrogen was calculated assuming an internal rate of return of 10%.

  10. Nuclear reactor control

    DOE Patents [OSTI]

    Cawley, William E. (Phoenix, AZ); Warnick, Robert F. (Pasco, WA)

    1982-01-01T23:59:59.000Z

    1. In a nuclear reactor incorporating a plurality of columns of tubular fuel elements disposed in horizontal tubes in a mass of graphite wherein water flows through the tubes to cool the fuel elements, the improvement comprising at least one control column disposed in a horizontal tube including fewer fuel elements than in a normal column of fuel elements and tubular control elements disposed at both ends of said control column, and means for varying the horizontal displacement of the control column comprising a winch at the upstream end of the control column and a cable extending through the fuel and control elements and attached to the element at the downstream end of the column.

  11. Nuclear reactor control apparatus

    DOE Patents [OSTI]

    Sridhar, Bettadapur N. (Cupertino, CA)

    1983-10-25T23:59:59.000Z

    Nuclear reactor safety rod release apparatus comprises a ring which carries detents normally positioned in an annular recess in outer side of the rod, the ring being held against the lower end of a drive shaft by magnetic force exerted by a solenoid carried by the drive shaft. When the solenoid is de-energized, the detent-carrying ring drops until the detents contact a cam surface associated with the lower end of the drive shaft, at which point the detents are cammed out of the recess in the safety rod to release the rod from the drive shaft. In preferred embodiments of the invention, an additional latch is provided to release a lower portion of a safety rod under conditions that may interfere with movement of the entire rod.

  12. Nuclear reactor control

    SciTech Connect (OSTI)

    Cawley, W.E.; Warnick, R.F.

    1982-03-30T23:59:59.000Z

    In a nuclear reactor incorporating a plurality of columns of tubular fuel elements disposed in horizontal tubes in a mass of graphite wherein water flows through the tubes to cool the fuel elements, the improvement comprising at least one control column disposed in a horizontal tube including fewer fuel elements than in a normal column of fuel elements and tubular control elements disposed at both ends of said control column, and means for varying the horizontal displacement of the control column comprising a winch at the upstream end of the control column and a cable extending through the fuel and control elements and attached to the element at the downstream end of the column.

  13. High Temperature Reactor (HTR) Deep Burn Core and Fuel Analysis: Design Selection for the Prismatic Block Reactor

    SciTech Connect (OSTI)

    Francesco Venneri; Chang-Keun Jo; Jae-Man Noh; Yonghee Kim; Claudio Filippone; Jonghwa Chang; Chris Hamilton; Young-Min Kim; Ji-Su Jun; Moon-Sung Cho; Hong-Sik Lim; MIchael A. Pope; Abderrafi M. Ougouag; Vincent Descotes; Brian Boer

    2010-09-01T23:59:59.000Z

    The Deep Burn (DB) Project is a U.S. Department of Energy sponsored feasibility study of Transuranic Management using high burnup fuel in the high temperature helium cooled reactor (HTR). The DB Project consists of seven tasks: project management, core and fuel analysis, spent fuel management, fuel cycle integration, TRU fuel modeling, TRU fuel qualification, and HTR fuel recycle. In the Phase II of the Project, we conducted nuclear analysis of TRU destruction/utilization in the HTR prismatic block design (Task 2.1), deep burn fuel/TRISO microanalysis (Task 2.3), and synergy with fast reactors (Task 4.2). The Task 2.1 covers the core physics design, thermo-hydraulic CFD analysis, and the thermofluid and safety analysis (low pressure conduction cooling, LPCC) of the HTR prismatic block design. The Task 2.3 covers the analysis of the structural behavior of TRISO fuel containing TRU at very high burnup level, i.e. exceeding 50% of FIMA. The Task 4.2 includes the self-cleaning HTR based on recycle of HTR-generated TRU in the same HTR. Chapter IV contains the design and analysis results of the 600MWth DB-HTR core physics with the cycle length, the average discharged burnup, heavy metal and plutonium consumptions, radial and axial power distributions, temperature reactivity coefficients. Also, it contains the analysis results of the 450MWth DB-HTR core physics and the analysis of the decay heat of a TRU loaded DB-HTR core. The evaluation of the hot spot fuel temperature of the fuel block in the DB-HTR (Deep-Burn High Temperature Reactor) core under full operating power conditions are described in Chapter V. The investigated designs are the 600MWth and 460MWth DB-HTRs. In Chapter VI, the thermo-fluid and safety of the 600MWth DB-HTRs has been analyzed to investigate a thermal-fluid design performance at the steady state and a passive safety performance during an LPCC event. Chapter VII describes the analysis results of the TRISO fuel microanalysis of the 600MWth and 450MWth DB-HTRs. The TRISO fuel microanalysis covers the gas pressure buildup in a coated fuel particle including helium production, the thermo-mechanical behavior of a CFP, the failure probabilities of CFPs, the temperature distribution in a CPF, and the fission product (FP) transport in a CFP and a graphite. In Chapter VIII, it contains the core design and analysis of sodium cooled fast reactor (SFR) with deep burn HTR reactor. It considers a synergistic combination of the DB-MHR and an SFR burner for a safe and efficient transmutation of the TRUs from LWRs. Chapter IX describes the design and analysis results of the self-cleaning (or self-recycling) HTR core. The analysis is considered zero and 5-year cooling time of the spent LWR fuels.

  14. Extreme helium stars: non-LTE matters Helium and hydrogen spectra of the unique objects V652 Her and HD144941

    E-Print Network [OSTI]

    N. Przybilla; K. Butler; U. Heber; C. S. Jeffery

    2005-10-03T23:59:59.000Z

    Quantitative analyses of low-mass hydrogen-deficient (super-)giant stars - so-called extreme helium stars - to date face two major difficulties. First, theory fails to reproduce the observed helium lines in their entirety, wings and line cores. Second, a general mismatch exists for effective temperatures derived from ionization equilibria and from spectral energy distributions. Here, we demonstrate how the issue can be resolved using state-of-the-art non-LTE line-formation for these chemically peculiar objects. Two unique high-gravity B-type objects are discussed in detail, the pulsating variable V652 Her and the metal-poor star HD144941. In the first case atmospheric parameters from published LTE analyses are largely recovered, in the other a systematic offset is found. Hydrogen abundances are systematically smaller than previously reported, by up to a factor ~2. Extreme helium stars turn out to be important testbeds for non-LTE model atoms for helium. Improved non-LTE computations show that analyses assuming LTE or based on older non-LTE model atoms can predict equivalent widths, for the HeI 10830A transition in particular, in error by up to a factor ~3.

  15. PHYSICAL REVIEW A 84, 062512 (2011) XUV frequency-comb metrology on the ground state of helium

    E-Print Network [OSTI]

    2011-01-01T23:59:59.000Z

    PHYSICAL REVIEW A 84, 062512 (2011) XUV frequency-comb metrology on the ground state of helium in a scheme of direct-frequency-comb excitation of helium atoms from the ground state to the 1s4p and 1s5p 1 P with a modulation contrast of up to 55%. Analysis of the visibility of this comb structure, thereby using the helium

  16. United States Domestic Research Reactor Infrastrucutre TRIGA Reactor Fuel Support

    SciTech Connect (OSTI)

    Douglas Morrell

    2011-03-01T23:59:59.000Z

    The United State Domestic Research Reactor Infrastructure Program at the Idaho National Laboratory manages and provides project management, technical, quality engineering, quality inspection and nuclear material support for the United States Department of Energy sponsored University Reactor Fuels Program. This program provides fresh, unirradiated nuclear fuel to Domestic University Research Reactor Facilities and is responsible for the return of the DOE-owned, irradiated nuclear fuel over the life of the program. This presentation will introduce the program management team, the universities supported by the program, the status of the program and focus on the return process of irradiated nuclear fuel for long term storage at DOE managed receipt facilities. It will include lessons learned from research reactor facilities that have successfully shipped spent fuel elements to DOE receipt facilities.

  17. Reactor protection system design alternatives for sodium fast reactors

    E-Print Network [OSTI]

    DeWitte, Jacob D. (Jacob Dominic)

    2011-01-01T23:59:59.000Z

    Historically, unprotected transients have been viewed as design basis events that can significantly challenge sodium-cooled fast reactors. The perceived potential consequences of a severe unprotected transient in a ...

  18. Reactor physics design of supercritical CO?-cooled fast reactors

    E-Print Network [OSTI]

    Pope, Michael A. (Michael Alexander)

    2004-01-01T23:59:59.000Z

    Gas-Cooled Fast Reactors (GFRs) are among the GEN-IV designs proposed for future deployment. Driven by anticipated plant cost reduction, the use of supercritical CO? (S-CO?) as a Brayton cycle working fluid in a direct ...

  19. Nuclear reactor downcomer flow deflector

    DOE Patents [OSTI]

    Gilmore, Charles B. (Greensburg, PA); Altman, David A. (Pittsburgh, PA); Singleton, Norman R. (Murrysville, PA)

    2011-02-15T23:59:59.000Z

    A nuclear reactor having a coolant flow deflector secured to a reactor core barrel in line with a coolant inlet nozzle. The flow deflector redirects incoming coolant down an annulus between the core barrel and the reactor vessel. The deflector has a main body with a front side facing the fluid inlet nozzle and a rear side facing the core barrel. The rear side of the main body has at least one protrusion secured to the core barrel so that a gap exists between the rear side of the main body adjacent the protrusion and the core barrel. Preferably, the protrusion is a relief that circumscribes the rear side of the main body.

  20. Conceptual design study on very small long-life gas cooled fast reactor using metallic natural Uranium-Zr as fuel cycle input

    SciTech Connect (OSTI)

    Monado, Fiber, E-mail: fiber.monado@gmail.com [Nuclear Physics and Biophysics Research Group, Dept. of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Bandung, Indonesia and Dept. of Physics, Faculty of Mathematics and Natural Sciences, Sriwijaya University (Indonesia); Ariani, Menik [Dept. of Physics, Faculty of Mathematics and Natural Sciences, Sriwijaya University (Indonesia); Su'ud, Zaki; Waris, Abdul; Basar, Khairul; Permana, Sidik [Nuclear Physics and Biophysics Research Group, Dept. of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Bandung (Indonesia); Aziz, Ferhat [National Nuclear Energy Agency of Indonesia (BATAN) (Indonesia); Sekimoto, Hiroshi [CRINES, Tokyo Institute of Technology, O-okoyama, Meguro-ku, Tokyo 152-8550 (Japan)

    2014-02-12T23:59:59.000Z

    A conceptual design study of very small 350 MWth Gas-cooled Fast Reactors with Helium coolant has been performed. In this study Modified CANDLE burn-up scheme was implemented to create small and long life fast reactors with natural Uranium as fuel cycle input. Such system can utilize natural Uranium resources efficiently without the necessity of enrichment plant or reprocessing plant. The core with metallic fuel based was subdivided into 10 regions with the same volume. The fresh Natural Uranium is initially put in region-1, after one cycle of 10 years of burn-up it is shifted to region-2 and the each region-1 is filled by fresh Natural Uranium fuel. This concept is basically applied to all axial regions. The reactor discharge burn-up is 31.8% HM. From the neutronic point of view, this design is in compliance with good performance.