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Title: Solid-Core, Gas-Cooled Reactor for Space and Surface Power

Abstract

The solid-core, gas-cooled, Submersion-Subcritical Safe Space (S and 4) reactor is developed for future space power applications and avoidance of single point failures. The Mo-14%Re reactor core is loaded with uranium nitride fuel in enclosed cavities, cooled by He-30%Xe, and sized to provide 550 kWth for seven years of equivalent full power operation. The beryllium oxide reflector disassembles upon impact on water or soil. In addition to decreasing the reactor and shadow shield mass, Spectral Shift Absorber (SSA) materials added to the reactor core ensure that it remains subcritical in the worst-case submersion accident. With a 0.1 mm thick boron carbide coating on the outside surface of the core block and 0.25 mm thick iridium sleeves around the fuel stacks, the reflector outer diameter is 43.5 cm and the combined reactor and shadow shield mass is 935.1 kg. With 12.5 atom% gadolinium-155 added to the fuel, 2.0 mm diameter gadolinium-155 sesquioxide intersititial pins, and a 0.1 mm thick gadolinium-155 sesquioxide coating, the S and 4 reactor has a slightly smaller reflector outer diameter of 43.0 cm, and a total reactor and shield mass of 901.7 kg. With 8.0 atom% europium-151 added to the fuel, 2.0 mm diameter europium-151 sesquioxide interstitialmore » pins, and a 0.1 mm thick europium-151 sesquioxide coating, the reflector's outer diameter and the total reactor and shield mass are further reduced to 41.5 cm and 869.2 kg, respect0011ive.« less

Authors:
;  [1];  [2]
  1. Institute for Space and Nuclear Power Studies, University of New Mexico, Albuquerque, NM 87131 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
20797988
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 813; Journal Issue: 1; Conference: 10. conference on thermophysics applications in microgravity; 23. symposium on space nuclear power and propulsion; 4. conference on human/robotic technology and the national vision for space exploration; 4. symposium on space colonization; 3. symposium on new frontiers and future concepts, Albuquerque, NM (United States), 12-16 Feb 2006; Other Information: DOI: 10.1063/1.2169206; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; BERYLLIUM OXIDES; BORON CARBIDES; EUROPIUM 151; GADOLINIUM 155; GAS COOLED REACTORS; IRIDIUM; POWER GENERATION; POWER SYSTEMS; REACTOR CORES; REACTOR MATERIALS; SHIELDS; SPACE; SPACE VEHICLES; SPECTRAL SHIFT; SURFACES; URANIUM NITRIDES; NESDPS Office of Nuclear Energy Space and Defense Power Systems

Citation Formats

King, Jeffrey C., El-Genk, Mohamed S., and Chemical and Nuclear Engineering Dept., University of New Mexico, Albuquerque, NM 87131. Solid-Core, Gas-Cooled Reactor for Space and Surface Power. United States: N. p., 2006. Web. doi:10.1063/1.2169206.
King, Jeffrey C., El-Genk, Mohamed S., & Chemical and Nuclear Engineering Dept., University of New Mexico, Albuquerque, NM 87131. Solid-Core, Gas-Cooled Reactor for Space and Surface Power. United States. doi:10.1063/1.2169206.
King, Jeffrey C., El-Genk, Mohamed S., and Chemical and Nuclear Engineering Dept., University of New Mexico, Albuquerque, NM 87131. Fri . "Solid-Core, Gas-Cooled Reactor for Space and Surface Power". United States. doi:10.1063/1.2169206.
@article{osti_20797988,
title = {Solid-Core, Gas-Cooled Reactor for Space and Surface Power},
author = {King, Jeffrey C. and El-Genk, Mohamed S. and Chemical and Nuclear Engineering Dept., University of New Mexico, Albuquerque, NM 87131},
abstractNote = {The solid-core, gas-cooled, Submersion-Subcritical Safe Space (S and 4) reactor is developed for future space power applications and avoidance of single point failures. The Mo-14%Re reactor core is loaded with uranium nitride fuel in enclosed cavities, cooled by He-30%Xe, and sized to provide 550 kWth for seven years of equivalent full power operation. The beryllium oxide reflector disassembles upon impact on water or soil. In addition to decreasing the reactor and shadow shield mass, Spectral Shift Absorber (SSA) materials added to the reactor core ensure that it remains subcritical in the worst-case submersion accident. With a 0.1 mm thick boron carbide coating on the outside surface of the core block and 0.25 mm thick iridium sleeves around the fuel stacks, the reflector outer diameter is 43.5 cm and the combined reactor and shadow shield mass is 935.1 kg. With 12.5 atom% gadolinium-155 added to the fuel, 2.0 mm diameter gadolinium-155 sesquioxide intersititial pins, and a 0.1 mm thick gadolinium-155 sesquioxide coating, the S and 4 reactor has a slightly smaller reflector outer diameter of 43.0 cm, and a total reactor and shield mass of 901.7 kg. With 8.0 atom% europium-151 added to the fuel, 2.0 mm diameter europium-151 sesquioxide interstitial pins, and a 0.1 mm thick europium-151 sesquioxide coating, the reflector's outer diameter and the total reactor and shield mass are further reduced to 41.5 cm and 869.2 kg, respect0011ive.},
doi = {10.1063/1.2169206},
journal = {AIP Conference Proceedings},
number = 1,
volume = 813,
place = {United States},
year = {Fri Jan 20 00:00:00 EST 2006},
month = {Fri Jan 20 00:00:00 EST 2006}
}
  • Reactor dynamics and system stability studies are performed on a conceptual burst-mode gaseous core reactor space nuclear power system. This concept operates on a closed Brayton cycle in the burst mode (on the order of 100-MW output for a few thousand seconds) using a disk magnetohydrodynamic generator for energy conversion. The fuel is a gaseous mixture of UF[sub 4] or UF[sub 6] and helium. Nonlinear dynamic analysis is performed using circulating-fuel, point-reactor-kinetics equations along with thermodynamic, lumped-parameter heat transfer and one-dimensional isentropic flow equations. The gaseous nature of the fuel plus the fact that the fuel is circulating lead tomore » dynamic behavior that is quite different from that of conventional solid-core systems. For the transients examined, Doppler fuel temperature and moderator temperature feedbacks are insignificant when compared with reactivity feedback associated with fuel gas density variations. The gaseous fuel density power coefficient of reactivity is capable of rapidly stabilizing the system, within a few seconds, even when large positive reactivity insertions are imposed; however, because of the strength of this feedback, standard external reactivity insertions alone are inadequate to bring about significant power level changes during normal reactor operation. Additional methods of reactivity control, such as changes in the gaseous of fuel mass flow rate or core inlet pressure, are required to achieve desired power level control. Finally, linear stability analysis gives results that are qualitatively in agreement with the nonlinear analysis.« less
  • This paper reports that cermet fuel elements, when integrated in a cylindrical core along with reflectors and safety and control components, constitute a very rugged reactor assembly capable of delivering hundreds of megawatts of power at power densities of several gigawatts per cubic metre (several megawatts per litre). The cermet fuel is a ceramic uranium oxide or uranium nitride fuel in a refractory metal matrix fuel element. The fuel element is hexagonal with a flat-to-flat dimension of 20 to 30 mm. Coolant channels of {approximately}1-mm diam are bored along the hexagonal fuel element. A typical cylindrical active core would havemore » a volume of {approximately}6 {times} 10{sup {minus}2} m{sup 3} (420 mm in height and diameter) with the core, reflectors, control and safety elements, core support, vessel, and reentry shield cone under 2000 kg. Depending on the particular choice of materials and desired performance characteristics, this reactor can operate at an exit temperature of up to 2700 K. The broad applications of this reactor type include steady-state space platform or lunar base power sources, burst power sources hundreds of megawatts (thermal) power on demand within 100 s for periods of minutes, and other applications.« less
  • A human outpost on Mars requires plentiful power to assure survival of the astronauts. Anywhere from 50 to 500 kW of electric power (kWe) will be needed, depending on the number of astronauts, level of scientific activity, and life-cycle closure desired. This paper describes a 250-kWe power system based on a gas-cooled nuclear reactor with a recuperated closed Brayton cycle conversion system. The design draws upon the extensive data and engineering experience developed under the various high-temperature gas cooled reactor programs and under the SP-100 program. The reactor core is similar in power and size to the research reactors foundmore » on numerous university campuses. The fuel is uranium nitride clad in Nb1{percent}Zr, which has been extensively tested under the SP-100 program. The fuel rods are arranged in a hexagonal array within a BeO block. The BeO softens the spectrum, allowing better use of the fuel and stabilizing the geometry against deformation during impact or other loadings. The system has a negative temperature feedback coefficient so that the power level will automatically follow a variable load without the need for continuous adjustment of control elements. Waste heat is removed by an air-cooled heat exchanger using cold Martian air. The amount of radioactivity in the reactor at launch is very small (less than a Curie, and about equal to a truckload of uranium ore). The system will need to be engineered so that criticality can not occur for any launch accident. This system is also adaptable for electric propulsion or life-support during transit to and from Mars. {copyright} {ital 1999 American Institute of Physics.}« less
  • The heat transfer properties vary considerably along the length of polyzonal spiral fuel elements. These variations result in hot spots, which limit reactor output. A largescale model cam, constructed to allow a detailed survey to be made of fluid flow and heat transfer patterns, is scribed together with the experimental techniques employed. The experimentel results enable an analysis to be made of the factors contributing towards the pattern of axial heat transfer variation, and allow an approach to be adopted towards its elimination or reduction. (auth)
  • A human outpost on Mars requires plentiful power to assure survival of the astronauts. Anywhere from 50 to 500 kW of electric power (kWe) will be needed, depending on the number of astronauts, level of scientific activity, and life-cycle closure desired. This paper describes a 250-kWe power system based on a gas-cooled nuclear reactor with a recuperated closed Brayton cycle conversion system. The design draws upon the extensive data and engineering experience developed under the various high-temperature gas cooled reactor programs and under the SP-100 program. The reactor core is similar in power and size to the research reactors foundmore » on numerous university campuses. The fuel is uranium nitride clad in Nb1%Zr, which has been extensively tested under the SP-100 program. The fuel rods are arranged in a hexagonal array within a BeO block. The BeO softens the spectrum, allowing better use of the fuel and stabilizing the geometry against deformation during impact or other loadings. The system has a negative temperature feedback coefficient so that the power level will automatically follow a variable load without the need for continuous adjustment of control elements. Waste heat is removed by an air-cooled heat exchanger using cold Martian air. The amount of radioactivity in the reactor at launch is very small (less than a Curie, and about equal to a truckload of uranium ore). The system will need to be engineered so that criticality can not occur for any launch accident. This system is also adaptable for electric propulsion or life-support during transit to and from Mars.« less