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.
How Small Can Fast‐Spectrum Space Reactors Get?
SPACE TECH.& APPLIC.INT.FORUM-STAIF 2006: 10th Conf Thermophys Applic Microgravity; 23rd Symp Space Nucl Pwr & Propulsion; 4th Conf Human/Robotic Tech & Nat'l Vision for Space Explor.; 4th Symp Space Coloniz.; 3rd Symp on New Frontiers & Future Concepts ; 2006 ; Albuquerque, New Mexico (USA)
AIP Conference Proceedings ; 813 , 1 ; 426-436
2006-01-20
11 pages
Conference paper
Electronic Resource
English
How Small Can Fast-Spectrum Space Reactors Get?
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