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

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:
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
Research Org:
University of Florida (US)
Sponsoring Org:
(US)
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