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Title: Development of Liquid-Vapor Core Reactors with MHD Generator for Space Power and Propulsion Applications

Abstract

Any reactor that utilizes fuel consisting of a fissile material in a gaseous state may be referred to as a gaseous core reactor (GCR). Studies on GCRs have primarily been limited to the conceptual phase, mostly due to budget cuts and program cancellations in the early 1970's. A few scientific experiments have been conducted on candidate concepts, primarily of static pressure fissile gas filling a cylindrical or spherical cavity surrounded by a moderating shell, such as beryllium, heavy water, or graphite. The main interest in this area of nuclear power generation is for space applications. The interest in space applications has developed due to the promise of significant enhancement in fuel utilization, safety, plant efficiency, special high-performance features, load-following capabilities, power conversion optimization, and other key aspects of nuclear power generation. The design of a successful GCR adapted for use in space is complicated. The fissile material studied in the pa st has been in a fluorine compound, either a tetrafluoride or a hexafluoride. Both of these molecules have an impact on the structural material used in the making of a GCR. Uranium hexafluoride as a fuel allows for a lower operating temperature, but at temperatures greater than 900K becomesmore » essentially impossible to contain. This difficulty with the use of UF6 has caused engineers and scientists to use uranium tetrafluoride, which is a more stable molecule but has the disadvantage of requiring significantly higher operating temperatures. Gas core reactors have traditionally been studied in a steady state configuration. In this manner a fissile gas and working fluid are introduced into the core, called a cavity, that is surrounded by a reflector constructed of materials such as Be or BeO. These reactors have often been described as cavity reactors because the density of the fissile gas is low and criticality is achieved only by means of the reflector to reduce neutron leakage from the core. Still there are problems of containment since many of the proposed vessel materials such as W or Mo have high neutron cross sections making the design of a critical system difficult. There is also the possibility for a GCR to remain in a subcritical state, and by the use of a shockwave mechanism, increase the pressure and temperature inside the core to achieve criticality. This type of GCR is referred to as a shockwave-driven pulsed gas core reactor. These two basic designs were evaluated as advance concepts for space power and propulsion.« less

Authors:
Publication Date:
Research Org.:
University of Florida (US)
Sponsoring Org.:
(US)
OSTI Identifier:
799231
Report Number(s):
DOE/ID/13635
TRN: US0204970
DOE Contract Number:
FG07-98ID13635
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 13 Aug 2002
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; 29 ENERGY PLANNING, POLICY AND ECONOMY; 30 DIRECT ENERGY CONVERSION; BUILDING MATERIALS; CROSS SECTIONS; FISSILE MATERIALS; FLUORINE COMPOUNDS; HEAVY WATER; MHD GENERATORS; NEUTRON LEAKAGE; NUCLEAR POWER; PROPULSION; URANIUM HEXAFLUORIDE; URANIUM TETRAFLUORIDE; WORKING FLUIDS; NESDPS Office of Nuclear Energy Space and Defense Power Systems

Citation Formats

Samim Anghaie. Development of Liquid-Vapor Core Reactors with MHD Generator for Space Power and Propulsion Applications. United States: N. p., 2002. Web. doi:10.2172/799231.
Samim Anghaie. Development of Liquid-Vapor Core Reactors with MHD Generator for Space Power and Propulsion Applications. United States. doi:10.2172/799231.
Samim Anghaie. Tue . "Development of Liquid-Vapor Core Reactors with MHD Generator for Space Power and Propulsion Applications". United States. doi:10.2172/799231. https://www.osti.gov/servlets/purl/799231.
@article{osti_799231,
title = {Development of Liquid-Vapor Core Reactors with MHD Generator for Space Power and Propulsion Applications},
author = {Samim Anghaie},
abstractNote = {Any reactor that utilizes fuel consisting of a fissile material in a gaseous state may be referred to as a gaseous core reactor (GCR). Studies on GCRs have primarily been limited to the conceptual phase, mostly due to budget cuts and program cancellations in the early 1970's. A few scientific experiments have been conducted on candidate concepts, primarily of static pressure fissile gas filling a cylindrical or spherical cavity surrounded by a moderating shell, such as beryllium, heavy water, or graphite. The main interest in this area of nuclear power generation is for space applications. The interest in space applications has developed due to the promise of significant enhancement in fuel utilization, safety, plant efficiency, special high-performance features, load-following capabilities, power conversion optimization, and other key aspects of nuclear power generation. The design of a successful GCR adapted for use in space is complicated. The fissile material studied in the pa st has been in a fluorine compound, either a tetrafluoride or a hexafluoride. Both of these molecules have an impact on the structural material used in the making of a GCR. Uranium hexafluoride as a fuel allows for a lower operating temperature, but at temperatures greater than 900K becomes essentially impossible to contain. This difficulty with the use of UF6 has caused engineers and scientists to use uranium tetrafluoride, which is a more stable molecule but has the disadvantage of requiring significantly higher operating temperatures. Gas core reactors have traditionally been studied in a steady state configuration. In this manner a fissile gas and working fluid are introduced into the core, called a cavity, that is surrounded by a reflector constructed of materials such as Be or BeO. These reactors have often been described as cavity reactors because the density of the fissile gas is low and criticality is achieved only by means of the reflector to reduce neutron leakage from the core. Still there are problems of containment since many of the proposed vessel materials such as W or Mo have high neutron cross sections making the design of a critical system difficult. There is also the possibility for a GCR to remain in a subcritical state, and by the use of a shockwave mechanism, increase the pressure and temperature inside the core to achieve criticality. This type of GCR is referred to as a shockwave-driven pulsed gas core reactor. These two basic designs were evaluated as advance concepts for space power and propulsion.},
doi = {10.2172/799231},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Aug 13 00:00:00 EDT 2002},
month = {Tue Aug 13 00:00:00 EDT 2002}
}

Technical Report:

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  • A nuclear driven magnetohydrodynamic (MHD) generator system is proposed for the space nuclear applications of few hundreds of megawatts. The MHD generator is coupled to a vapor-droplet core reactor that delivers partially ionized fissioning plasma at temperatures in range of 3,000 to 4,000 K. A detailed MHD model is developed to analyze the basic electrodynamics phenomena and to perform the design analysis of the nuclear driven MHD generator. An incompressible quasi one dimensional model is also developed to perform parametric analyses.
  • An innovative reactor core design based on advanced, mixed carbide fuels was analyzed for nuclear space power applications. Solid solution, mixed carbide fuels such as (U,Zr,Nb)c and (U,Zr, Ta)C offer great promise as an advanced high temperature fuel for space power reactors.
  • During the period covered by this report (October 1988--March 1989), the following work was done: the mixing stream condensation process was analyzed, and a theoretical model for simulating this process was modified. A parametric study is being conducted at the present time; the separation processes were analyzed; and the experimental system was specified and its design is at present in an advanced stage. The mixing stream condensation process was analyzed. For the parameters defined in the SOW of this project the process was found to be a mist flow direct contact condensation, where the hot gas mixture consisting of inertmore » gas and vapor is the continuous phase, and the subcooled liquid on which the vapor is condensed if the droplets dispersed phase. Two possibilities of creating the mist flow were considered. The first, injecting the cold Liquid Metal (LM) into the Mixing Streams Condenser (MSC) entrance as a jet and breaking it into LM fragments and the fragments into droplets by momentum transfer breakup mechanism. The second, atomizing the cooled LM stream into little droplets (approximately 100 {mu}m in diameter) and accelerating them by the gas. The second possibility was preferred due to its much higher heat and mass transfer surface and coefficients relative to the first one. 3 refs., 13 figs.« less
  • A feasibility study for the approval of liquid metal seeds recovery from a liquid metal vapor-inert gas mixture was conducted and presented in this report. The research activity included background studies on processes relating to mixing stream condenser performance, parametric studies and its experimental validation. The condensation process under study includes mass transfer phenomena combined with heat transfer and phase change. Numerical methods were used in order to solve the dynamic equations and to carry out the parametric study as well as the experimental data reduction. The MSC performance is highly effected by droplet diameter, thus the possibility of atomizingmore » liquid metals were experimentally investigated. The results are generalized and finally used for a set of recommendations by which the recovery of seeds is expected to be feasible.« less