DynMo-TE: Dynamic simulation model of space reactor power system with thermoelectric converters

El‐Genk, Mohamed S.; Tournier, Jean‐Michel

doi:10.1016/j.nucengdes.2006.03.004

Cited by 29 publications

(13 citation statements)

References 33 publications

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“…After operating the reactor for months or years, the decay heat in the reactor core after shutdown would prevent the working fluid in the reactor's heat pipes from freezing for extended periods. In order to prolong the shutdown time of a nuclear reactor without freezing, the diameter of the radiator heat pipes could be made small to induce the sonic limit shortly after reactor shutdown (El-Genk, Buksa and Seo, 1988;Tournier, 2004a and2006b). The resulting decrease in heat rejection would increase the time before the reactor working fluid freezes.…”

Section: Fundamentals Of Heat Pipesmentioning

confidence: 99%

“…(e) Normal operation Figure 16 shows a typical, fully deployed space nuclear reactor power system (El-Genk, 2008a,b;El-Genk and Tournier, 2006b) with a liquidmetal heat pipes radiator. The power systems also has six pairs of primary and secondary loops with circulating liquid-metal working fluids, and thermoelectric energy conversion elements thermally coupled to the primary and secondary loops.…”

Section: Hptam Simulation Of a Water Heat Pipe Startupmentioning

confidence: 99%

“…When the 12 rear segments of the radiator panels are folded onto the 6 forward segments, the stowed power system (Fig. 19) fits in the fairing envelop of the DELTA-IV Heavy launch vehicle, configured in a dual-manifest arrangement (El-Genk and Tournier, 2006b;2006). When the radiator is fully deployed (Figs.…”

Section: Hptam Simulation Of a Water Heat Pipe Startupmentioning

confidence: 99%

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Uses of Liquid-Metal and Water Heat Pipes in Space Reactor Power Systems

El‐Genk¹,

Tournier²

2011

Frontiers in Heat Pipes

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Water and liquid-metal heat pipes are considered for redundant and passive cooling of nuclear reactors and redundant operation of light-weight heat rejection radiators of space reactor power systems. The systems operate continuously for many years independent of the Sun, are enabling of deep space exploration and could provide 10's of kilowatts of electrical power for lunar and Martian outposts. Space reactors typically operate at 900 K -1400 K could be cooled using liquid-metal heat pipes with either sodium (900 -1100 K) or lithium (1100 K-1400 K) working fluids. The heat rejection temperatures dictate the working fluid of the radiator heat pipes; potassium for 600 -800 K, rubidium for 500 -700 K, and water for < 500 K. These working fluids would be frozen prior to starting up the power systems in orbit or at destination. The startup of water and liquid-metal heat pipes from a frozen state is complex, involving a number of non-linear mass and heat transport processes that require implementing appropriate procedures, depending on the type of working fluid. This paper reviews operation and design constraints pertinent to the uses of water and liquidmetal heat pipes in space reactor systems, and the modeling capabilities of the startup from a frozen state. In addition to models validation, results of design optimization of liquid-metal and water heat pipes in a number of space reactor power systems are presented and discussed.

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Section: Fundamentals Of Heat Pipesmentioning

confidence: 99%

Section: Hptam Simulation Of a Water Heat Pipe Startupmentioning

confidence: 99%

Section: Hptam Simulation Of a Water Heat Pipe Startupmentioning

confidence: 99%

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Uses of Liquid-Metal and Water Heat Pipes in Space Reactor Power Systems

El‐Genk¹,

Tournier²

2011

Frontiers in Heat Pipes

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“…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%

“…A number of dynamic simulation models of different space reactor power systems have been developed [4,[14][15][16][17][18][19]. The Space Nuclear Power Systems Analysis Model for the SP-100 system [20,21], with a fast-spectrum reactor heat source and multiple circulating liquid lithium loops with thermoelectric-electromagnetic (TEM) pumps and Silicon-Germanium (SiGe) thermoelectric (TE) conversion modules, had been developed and successfully validated by comparing predictions with reported simulation results by General Electric Company [15][16][17].…”

mentioning

confidence: 99%

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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Thermal‐hydraulic analysis of gas‐cooled space nuclear reactor power system with closed Brayton cycle

et al. 2020

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Summary Space nuclear reactor power system (SNRPS), especially megawatt power level, is very attractive for the future civil and military space demands. The high‐temperature gas‐cooled reactor coupled with closed Brayton cycle (CBC) can achieve high‐power output for space applications. For the gas‐cooled SNRPS with CBC, dynamic models for all components, including reactor, turbine, compressor, alternator, ducting, pump, recuperator, gas cooler and heat pipe radiator, are developed in this article. Then, a transient system analysis code (SAC‐SPACE) is developed to perform the safety characteristics analysis of the SNRPS. In the full‐power steady‐state analysis, the maximum fuel temperature has a margin of 1323 K from the melting point. Moreover, the transient responses of the SNRPS under the mechanical failure of one Brayton loop (MFOBL1) and the reactivity insertion accident (RIA) are simulated and analyzed. During the MFOBL1, the maximum fuel temperature is 1275 K lower than the melting point, and finally, the reactor power stabilizes at 56.8% of the rated power. For the RIA, as long as the reactivity introduced into the core does not exceed 0.61 $, the SNRPS can reach a new steady‐state safely by itself without other protection strategies. It can be concluded that the SNRPS has good self‐stability due to the negative reactivity feedback of the reactor. This article may provide useful theoretical supports for the design and safety analysis of the gas‐cooled SNRPS with CBC.

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DynMo-TE: Dynamic simulation model of space reactor power system with thermoelectric converters

Cited by 29 publications

References 33 publications

Uses of Liquid-Metal and Water Heat Pipes in Space Reactor Power Systems

Uses of Liquid-Metal and Water Heat Pipes in Space Reactor Power Systems

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

Thermal‐hydraulic analysis of gas‐cooled space nuclear reactor power system with closed Brayton cycle

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