How Small Can Fast-Spectrum Space Reactors Get?

Journal Article · Fri Jan 20 04:00:00 EST 2006 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2169220· OSTI ID:20797996

Hatton, Steven A; El-Genk, Mohamed S ^[1]

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

Fast neutron spectrum space reactors are an appropriate choice for high thermal powers, but for low powers, they may not satisfy the excess reactivity requirement while remaining sub-critical when immersed in wet sand and flooded with seawater following a launch abort accident. This paper identifies the smallest size fast spectrum, Sectored, Compact Reactor loaded with Single UN fuel pins (SCoRe-S7), which satisfy the requirements of cold clean excess reactivity > $4.00 and remains at least $1.00 subcritical at shutdown and in submersion conditions. Results indicate that increasing the diameter of the SCoRe-S core reduces its active height and the UN fuel enrichment, but increases the Spectrum-Shift Absorber (SSA) of 157GdN additive to the fuel. All SCoRe-S cores also have a 0.1 mm thick 157Gd2O3 SSA coating on the outer surface of the reactor vessel to reduce the effect of the wet sand reflector, while the SSA fuel additive reduces the effect on the criticality of the flooded reactor caused by thermal neutron fission. The active core height decreases from 42.4 cm for the smallest SCoRe-S7 to as much as to 37.4 cm for the largest core of SCoRe-S11. For a 1.8 MWth reactor thermal power the UN fuel specific power decreases from 17.0 in the SCoRe-S7 to 11.5 Wth/kg in the -S11. The corresponding reactor total mass, including the BeO reflector, increases from 440 kg to 512 kg.

• OSTI ID: 20797996
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 813; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BERYLLIUM OXIDES
CRITICALITY
FAST NEUTRONS
FISSION
FUEL ADDITIVES
FUEL PINS
NESDPS Office of Nuclear Energy Space and Defense Power Systems
NEUTRON SPECTRA
REACTIVITY
REACTOR MATERIALS
REACTOR VESSELS
REACTORS
SPACE
SPACE VEHICLES
THERMAL NEUTRONS
URANIUM NITRIDES