Transport Properties of He-N{sub 2} Binary Gas Mixtures for CBC Space Applications

Journal Article · Mon Jan 21 00:00:00 EST 2008 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2845025· OSTI ID:21049486

Tournier, Jean-Michel P; El-Genk, Mohamed S ^[1]

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1. Institute for Space and Nuclear Power Studies and Chemical and Nuclear Engineering Department, University of New Mexico, Albuquerque, NM 87131 (United States)

In order to reduce the size and mass of the single-shaft turbo-machines, with little impact on the size of the heat transfer components in the CBC loop, He-Xe binary mixture with a molecular weight of 40 g/mole has been the working fluid of choice in space nuclear reactor power systems with Close Brayton Cycle (CBC) for energy conversion. This working fluid is also a suitable coolant for the fission reactors heat source designed with fast neutron energy spectra. For space nuclear reactors with thermal neutron energy spectra, however, the high capture neutron cross-section of Xe will reduce the beginning-of-life excess reactivity of the reactor, decreasing its effective operation lifetime. In addition, the neutron activation of Xe in the reactor will introduce a radioactivity source term in the CBC loop. Alternative working fluids with no activation concerns and comparable performance are N{sub 2} and the binary mixtures of He-N{sub 2}. This paper calculates the transport properties of these working fluids and compares their values to those of noble gas binary mixtures at the temperatures and pressures expected in CBC space reactor power system applications. Also investigated is the impact of using these working fluids on the pressure losses, heat transfer coefficient, and the aerodynamic loading of the blades in the CBC turbo-machines.

• OSTI ID: 21049486
• Journal Information: AIP Conference Proceedings, Vol. 969, Issue 1; Conference: Space Technology and Applications International Forum-STAIF 2008: 12. conference on thermophysics applications in microgravity; 1. symposium on space resource utilization; 25. symposium on space nuclear power and propulsion; 6. conference on human/robotic technology and the vision for space exploration; 6. symposium on space colonization; 5. symposium on new frontiers and future concept, Albuquerque, NM (United States), 10-14 Feb 2008; Other Information: DOI: 10.1063/1.2845025; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
BINARY MIXTURES
BRAYTON CYCLE
CAPTURE
COMPARATIVE EVALUATIONS
CROSS SECTIONS
DIRECT ENERGY CONVERSION
FAST NEUTRONS
FISSION
HEAT TRANSFER
HELIUM
LIFETIME
MASS
MOON
NEON
POWER GENERATION
REACTOR OPERATION
REACTORS
SPACE
THERMAL NEUTRONS
WORKING FLUIDS
NESDPS Office of Nuclear Energy Space and Defense Power Systems