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Title: Passive Safety Features in Sodium Cooled Super-Safe,Small and Simple Reactor

Abstract

This paper describes the passive safety features utilized in the updated sodium cooled Super-Safe, Small and Simple fast reactor, which is the improved 4S reactor. This reactor can operate up to ten years without refueling and neutron reflector regulates the reactivity. One of the design requirements is to secure the core against all anticipated transients without reactor scram. Therefore, the reactor concept is to design to enhance the passive safety features. All temperature reactivity feedback coefficients including whole core sodium void worth are negative. Also, introducing of RVACS (Reactor Vessel Auxiliary Cooling System) can enhance the passive decay heat removal capability. Safety analyses are carried out to simulate various transient sequences, which are loss of flow events, transient overpower events and loss of heat sink events, in order to evaluate the passive safety capabilities. A calculation tool for plant dynamics analyses for fast reactors has been modified to model the 4S including the unique plant system, which are reflector control system, circulation pumps and RVACS. The analytical results predict that the designed passive features improve the safety in which temperature variation in transients are satisfied with the safety criteria for the fuel element and the structure of the primary coolantmore » boundary. (authors)« less

Authors:
; ; ;  [1]; ;  [2]
  1. Central Research Institute of Electric Power Industry - CRIEPI (Japan)
  2. Toshiba Corporation (Japan)
Publication Date:
Research Org.:
The ASME Foundation, Inc., Three Park Avenue, New York, NY 10016-5990 (United States)
OSTI Identifier:
21064556
Resource Type:
Conference
Resource Relation:
Conference: ICONE-10: 10. international conference on nuclear engineering, Arlington - Virginia (United States), 14-18 Apr 2002; Other Information: Country of input: France
Country of Publication:
United States
Language:
English
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; AFTER-HEAT REMOVAL; CONTROL SYSTEMS; DESIGN; FAST REACTORS; FUEL ELEMENTS; HEAT SINKS; LOSS OF FLOW; NEUTRON REFLECTORS; PRIMARY COOLANT CIRCUITS; REACTIVITY; REACTIVITY COEFFICIENTS; REACTOR SAFETY; REACTOR VESSELS; SAFETY ANALYSIS; SCRAM; SODIUM

Citation Formats

Ueda, N., Kinoshita, I., Nishi, Y., Minato, A., Matsumiya, H., and Nishiguchi, Y. Passive Safety Features in Sodium Cooled Super-Safe,Small and Simple Reactor. United States: N. p., 2002. Web.
Ueda, N., Kinoshita, I., Nishi, Y., Minato, A., Matsumiya, H., & Nishiguchi, Y. Passive Safety Features in Sodium Cooled Super-Safe,Small and Simple Reactor. United States.
Ueda, N., Kinoshita, I., Nishi, Y., Minato, A., Matsumiya, H., and Nishiguchi, Y. 2002. "Passive Safety Features in Sodium Cooled Super-Safe,Small and Simple Reactor". United States. doi:.
@article{osti_21064556,
title = {Passive Safety Features in Sodium Cooled Super-Safe,Small and Simple Reactor},
author = {Ueda, N. and Kinoshita, I. and Nishi, Y. and Minato, A. and Matsumiya, H. and Nishiguchi, Y.},
abstractNote = {This paper describes the passive safety features utilized in the updated sodium cooled Super-Safe, Small and Simple fast reactor, which is the improved 4S reactor. This reactor can operate up to ten years without refueling and neutron reflector regulates the reactivity. One of the design requirements is to secure the core against all anticipated transients without reactor scram. Therefore, the reactor concept is to design to enhance the passive safety features. All temperature reactivity feedback coefficients including whole core sodium void worth are negative. Also, introducing of RVACS (Reactor Vessel Auxiliary Cooling System) can enhance the passive decay heat removal capability. Safety analyses are carried out to simulate various transient sequences, which are loss of flow events, transient overpower events and loss of heat sink events, in order to evaluate the passive safety capabilities. A calculation tool for plant dynamics analyses for fast reactors has been modified to model the 4S including the unique plant system, which are reflector control system, circulation pumps and RVACS. The analytical results predict that the designed passive features improve the safety in which temperature variation in transients are satisfied with the safety criteria for the fuel element and the structure of the primary coolant boundary. (authors)},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2002,
month = 7
}

Conference:
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  • CRIEPI has been exploring to realize a small-sized nuclear reactor for the needs of dispersed energy source and multi-purpose reactor. And a conceptual design of 4S (Super-Safe, Small and Simple) reactor was proposed to meet the following design requirements: (1) All temperature feedback reactivity coefficients including whole core sodium void coefficient are negative; (2) The core integrity is secured against all anticipated transient without reactor scram; (3) No emergency power nor active mitigating system is required; (4) The reactivity core life time is more than 10 years; (5) Its construction, maintenance and operation are expected to be very simple bymore » eliminating active components from inside of a reactor vessel. The 4S reactor is a sodium cooled fast reactor and its reactivity is not controlled by neutron absorber rods but by neutron reflectors. An electrical output is 50 MW. This paper describes a design modification to enhance the feasibility from the previous 4S design. A core active height can be shortened to 1.5 m from 4.0 m to keep the reactivity characteristics. An averaged fuel burn-up is up to 70 GWD/ton and a pressure drop at the core region is less than 0.1 MPa. A reactivity control system is modified according with the core design change. As for the steam generator design, sodium-water reaction accidents must be taken into account as a design basis event for the utilization of the secondary sodium coolant. Therefore, a modified plate type heat exchanger is proposed as a steam generator. It may be possible to develop a compact steam generator, which is free from sodium-water reaction accidents and to eliminate the secondary sodium systems. The 4S reactor without secondary system has been proposed as a candidate design. (authors)« less
  • A study has been performed on the passive safety features of low-sodium-void-worth metallic-fueled reactors with emphasis on using a bottom-supported reactor vessel design. The reactor core designs included self-sufficient types as well as actinide burners. The analyses covered the reactor response to the unprotected, i.e. unscrammed, transient overpower accident and the loss-of-flow accident. Results are given demonstrating the safety margins that were attained. 4 refs., 4 figs., 2 tabs.
  • Lands as large as 6 million ha (Ref. 1) are devastated annually to an unrecoverable extent in the world by desertification. Most desertification is concentrated in areas with low annual precipitation. To control desertification, a grassland or green bell must be made at the front of the desertification area. It is obvious that fresh water is needed in the required quantities at the proper times. A dual-purpose plant for electric power and water is significant in this case because desalination can be made available by power production, and supplying power to desertification areas leads to preservation of forests (when energymore » requirements in the area are met by wood fuel), preventing desertification in a double sense. This super-safe, small, and simple (4S) liquid-metal reactor with very low maintenance can be used to create a green belt at the front of a desertification area in conjunction with a module desalination system. In the green belt, a soil environment with adequate power to grow plants will be formed along with the development of surface soils that contain a significant quantity of organic materials. Desertification will eventually cease at this location and a vast green area will result.« less
  • As part of the Plateau Remediation Project at US Department of Energy's Hanford, Washington site, CH2M Hill Plateau Remediation Company (CHPRC) contracted with IMPACT Services, LLC to receive and deactivate approximately 28 cubic meters of sodium metal contaminated debris from two sodium-cooled research reactors (Enrico Fermi Unit 1 and the Fast Flux Test Facility) which had been stored at Hanford for over 25 years. CHPRC found an off-site team composed of IMPACT Services and Commodore Advanced Sciences, Inc., with the facilities and technological capabilities to safely and effectively perform deactivation of this sodium metal contaminated debris. IMPACT Services provided themore » licensed fixed facility and the logistical support required to receive, store, and manage the waste materials before treatment, and the characterization, manifesting, and return shipping of the cleaned material after treatment. They also provided a recycle outlet for the liquid sodium hydroxide byproduct resulting from removal of the sodium from reactor parts. Commodore Advanced Sciences, Inc. mobilized their patented AMANDA unit to the IMPACT Services site and operated the unit to perform the sodium removal process. Approximately 816 Kg of metallic sodium were removed and converted to sodium hydroxide, and the project was accomplished in 107 days, from receipt of the first shipment at the IMPACT Services facility to the last outgoing shipment of deactivated scrap metal. There were no safety incidents of any kind during the performance of this project. The AMANDA process has been demonstrated in this project to be both safe and effective for deactivation of sodium and NaK. It has also been used in other venues to treat other highly reactive alkali metals, such as lithium (Li), potassium (K), NaK and Cesium (Cs). (authors)« less
  • Public concern about the safety of nuclear power plants has resulted in a search for inherently safe plants. The concept of an inherently safe reactor presented in this paper responds to that need. The plant, rated at 340 MW(e), is based on the state-of-the-art technology of light water reactors and the high-temperature gas-cooled reactors (HTGRs). The reactor core uses shortened assemblies of the boiling water reactor (BWR)/6 design. The steam delivered to the turbines is generated in a secondary system similar to that in a pressurized concrete reactor vessel (PCRV) as in the HTGRs.