Temperature and burnup reactivities and operational lifetime for the submersion-subcritical, safe space (S∧4) reactor

King, Jeffrey C.; El‐Genk, Mohamed S.

doi:10.1016/j.nucengdes.2006.07.008

Cited by 15 publications

(7 citation statements)

References 12 publications

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“…The submersion-subcritical safe space (S^4) reactor [8][9][10] generates up to 471 kW th of steady-state thermal power for up to 12 years, shared equally among the three sectors of the core. Thus, each sector nominally generates up to 157 kW th .…”

Section: S^4 Reactormentioning

confidence: 99%

“…The 151 EuN neutron poison minimally affects the reactivity of the fast neutron energy spectrum, S^4 reactor during nominal operation. However, it effectively absorbs thermal neutrons produced in the submerged and flooded core during a launch abort accident, keeping it subcritical [8][9][10].…”

Section: S^4 Reactormentioning

confidence: 99%

“…For convectively cooled space reactors, an avoidance of singlepoint failures could be accomplished by 1) designing the reactor core with 3-6 sectors that are hydraulically independent but thermally and neutronically coupled, and 2) thermal-hydraulically coupling each reactor sector to a separate energy conversion loop or modules with a separate heat rejection loop and/or heat pipe radiator panels [1][2][3][4][5][6][7][8][9][10]. Thus, a pipe break in one of the energy conversion loops would not compromise the system operation and mission because the reactor fission power would be reduced, and the power generated in the sector with a failed energy conversion loop would be conducted to adjacent sectors where it is removed by the circulating liquid metal or gas coolant in these sectors.…”

mentioning

confidence: 99%

“…2). The reactor core is divided into three sectors that are hydraulically independent, but thermally and neutronically coupled [8][9][10] (Figs. 2a and 2b).…”

mentioning

confidence: 99%

“…It has been optimized for operating at peak thermal efficiency and electrical power of 28.5% and 44:7 kW e , respectively, when operating at turbine and compressor inlet temperatures of 1149 K and 400 K, respectively, shaft rotation speed of 45 krpm, and input thermal power to the turbine Q sec 157 kW th [26]. The corresponding reactor thermal power is 471 kW th , divided equally among the three core sectors [8][9][10].…”

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confidence: 99%

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Dynamic Simulation of a Space Reactor System with Closed Brayton Cycle Loops

El‐Genk

Tournier

Gallo

2010

Journal of Propulsion and Power

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A dynamic simulation model for space reactor power systems with multiple closed Brayton cycle loops for energy conversion is developed and demonstrated for a startup transient. The simulated power system employs a submersion-subcritical safe space S^4 reactor with a negative temperature reactivity feedback and has no singlepoint failures in reactor cooling and energy conversion. The S^4 reactor core is divided into three hydraulically independent sectors, and each sector has a separate closed Brayton cycle loop that is thermal-hydraulically coupled to a circulating liquid NaK-78 secondary loop with two water heat pipe heat rejection radiator panels. Each closed Brayton cycle loop has a Brayton rotating unit designed and optimized for high thermal efficiency and low specific mass (1:16 kg=kW e ). The reactor coolant and the closed Brayton cycle working fluid is a He-Xe binary gas mixture with a molecular weight of 40 g=mol. Results are presented for a startup transient of the S^4 closed Brayton cycle power system to full-power operation at a reactor thermal power 471 kW th , a Brayton rotating unit shaft speed of 45 krpm, and turbine and compressor inlet temperatures of 1149 and 400 K, respectively. At these conditions, the nominal electrical power and thermal efficiency of the power system are 130:8 kW e and 27.8%. NomenclatureC = compressor m = mass flow rate, kg=s m = normalized mass flow rate, kg=s, m m P ref =P o;in T o;in =T ref p P = pressure, Pa; electrical power, kW e P ref = reference pressure, 0.4 MPa T = temperature, K; turbine T ref = reference temperature, 400 K x = bleed fraction of working fluid at exit of Brayton rotating unit compressor = thermal or polytropic efficiency, % = pressure ratio ! = Brayton rotating unit shaft rotation speed, rad=s ! = normalized shaft rotation speed, rad=s, ! ! T ref =T o;in p Subscripts C = compressor e = electric G = generator in = turbine or compressor inlet o = stagnation or total P = polytropic Rx = reactor Sec = reactor sector, or BRU turbine inlet sys = power system th = thermal T = turbine

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Section: S^4 Reactormentioning

confidence: 99%

Section: S^4 Reactormentioning

confidence: 99%

mentioning

confidence: 99%

“…2). The reactor core is divided into three sectors that are hydraulically independent, but thermally and neutronically coupled [8][9][10] (Figs. 2a and 2b).…”

mentioning

confidence: 99%

mentioning

confidence: 99%

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