Dynamic simulation of a space gas-cooled reactor power system with a closed Brayton cycle

Abstract

Space nuclear reactor power (SNRP) using a gas-cooled reactor (GCR) and a closed Brayton cycle (CBC) is the ideal choice for future high-power space missions. To investigate the safety characteristics and develop the control strategies for gas-cooled SNRP, transient models for GCR, energy conversion unit, pipes, heat exchangers, pump and heat pipe radiator are established and a system analysis code is developed in this paper. Then, analyses of several operation conditions are performed using this code. In full-power steady-state operation, the core hot spot of 1293 K occurs near the upper part of the core. If 0.4 $ reactivity is introduced into the core, the maximum temperature that the fuel can reach is 2059 K, which is 914 K lower than the fuel melting point. The system finally has the ability to achieve a new steady-state with a higher reactor power. When the GCR is shut down in an emergency, the residual heat of the reactor can be removed through the conduction of the core and radiation heat transfer. The results indicate that the designed GCR is inherently safe owing to its negative reactivity feedback and passive decay heat removal. This paper may provide valuable references for safety design and analysis of the gas-cooled SNRP coupled with CBC.

Graphical abstract

Keywords

gas-cooled space nuclear reactor power / closed Brayton cycle / system startup and shutdown / positive reactivity insertion accident

References

[1] Wu W R, Liu J Z, Zhao X, System engineering research and application foreground of space nuclear reactor power generators. Scientia Sinica Technologica, 2019, 49(1): 1–12 (in Chinese)

[2] Akimov V N, Koroteev A A, Koroteev A S. Space nuclear power systems: yesterday, today, and tomorrow. Thermal Engineering, 2012, 59(13): 953–959

[3] Poston D I. The heat pipe-operated mars exploration reactor (HOMER). In: AIP Conference Proceedings 2001. American Institute of Physics, 2001, 552: 797–804

[4] Gibson M A, Poston D I, McClure P R, Heat transport and power conversion of the Kilopower reactor test. Nuclear Technology, 2020, 206(sup1): 31–42

[5] Staub D W. SNAP reactor programs: summary report. INIS Report AI-AEC-13067, 1973

[6] Demuth S F. SP100 space reactor design. Progress in Nuclear Energy, 2003, 42(3): 323–359

[7] Voss S S. TOPAZ-II design evolution. In: AIP Conference Proceedings 1994. American Institute of Physics, 1994, 301: 791–802

[8] Levine B L. Space nuclear power plant pre-conceptual design report, for information. INIS Report SPP-67210–0010, 2006

[9] Dragunov Y G. Fast-neutron gas-cooled reactor for the megawatt-class space bimodal nuclear thermal system. Engineering and Automation Problems, 2015, 2: 117–120 (in Russian)

[10] Hu G, Zhao S Z. Overview of space nuclear reactor power technology. Journal of Deep Space Exploration, 2017, 4(5): 430–443 (in Chinese)

[11] Li Y W, Zhang B L, Li Y H, Applications and prospects of magnetohydrodynamics in aeronautical engineering. Advances in Mechanics, 2017, 47: 452–502 (in Chinese)

[12] Ludewig H, Powell J R, Todosow M, Design of particle bed reactors for the space nuclear thermal propulsion program. Progress in Nuclear Energy, 1996, 30(1): 1–65

[13] El-Genk M S, Morley N J, Pelaccio D G, Pellet bed reactor concepts for nuclear propulsion applications. Journal of Propulsion and Power, 1994, 10(6): 817–827

[14] Li Z G, Sun J, Liu M L, Design of a hundred-kilowatt level integrated gas-cooled space nuclear reactor for deep space application. Nuclear Engineering and Design, 2020, 361: 110569

[15] Stewart M E M, Schnitzler B G. Thermal, fluid, and structural analysis of a cermet fuel element. In: Proceedings of the 48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, Atlanta, Georgia, USA, 2012

[16] Kruger G B, Lobach J. Application of cermet fueled reactors to multimegawatt space power systems. In: Proceedings of the 24th Intersociety Energy Conversion Engineering Conference, Washington, USA, 1989: 1125–1130

[17] Webb J A, Gross B J. A conceptual multi-megawatt system based on a tungsten cermet reactor. In: Proceedings of Nuclear and Emerging Technologies for Space 2011, Albuquerque, NM, USA, 2011: INL/CON-10–20348

[18] Jahshan S N, Kammash T. Multimegawatt nuclear reactor design for plasma propulsion systems. Journal of Propulsion and Power, 2005, 21(3): 385–391

[19] Meng T, Zhao F L, Cheng K, Neutronics analysis of megawatt-class gas-cooled space nuclear reactor design. Journal of Nuclear Science and Technology, 2019, 56(12): 1120–1129

[20] King J C, El-Genk M S. Submersion-Subcritical Safe Space (S⁴) reactor. Nuclear Engineering and Design, 2006, 236(17): 1759–1777

[21] Morley N J, El-Genk M S. Neutronics and thermal-hydraulics analyses of the pellet bed reactor for nuclear thermal propulsion. Nuclear Technology, 1995, 109(1): 87–107

[22] Zhang R, Liang Y, Liu X, Thermal-hydraulic analysis of pellet bed reactor for space nuclear electric propulsion. Annals of Nuclear Energy, 2020, 143: 107482

[23] King J C, El-Genk M S. Thermal-hydraulic and neutronic analyses of the submersion-subcritical, safe space (S⁴) reactor. Nuclear Engineering and Design, 2009, 239(12): 2809–2819

[24] Schillo K J, Kumar A, Harris K E, Neutronics and thermal hydraulics analysis of a low-enriched uranium cermet fuel core for a Mars surface power reactor. Annals of Nuclear Energy, 2016, 96: 307–312

[25] El-Genk M S, Tournier J P, Gallo B M. Dynamic simulation of a space reactor system with closed Brayton cycle loops. Journal of Propulsion and Power, 2010, 26(3): 394–406

[26] Zhang R, Guo K L, Wang C L, Thermal-hydraulic analysis of gas-cooled space nuclear reactor power system with closed Brayton cycle. International Journal of Energy Research, 2020, online,

[27] Wright S A, Lipinski R J, Vernon M E, Closed Brayton cycle power conversion systems for nuclear reactors: modeling, operations, and validation. New Mexico: Sandia National Laboratories, 2006

[28] Qin H, Zhang R, Guo K L, Thermal-hydraulic analysis of an open-grid megawatt gas-cooled space nuclear reactor core. International Journal of Energy Research, 2020, online, doi:10.1002/er.5329

[29] Gear C W. Numerical Initial Value Problems in Ordinary Differential Equations. Englewood Cliffs, NJ: Prentice-Hall, 1971

RIGHTS & PERMISSIONS

Higher Education Press