Abstract: Space nuclear reactor power supply has the advantages of self-generating energy，high power density，and long service life，suitable for high-power deep space exploration missions.Aiming at the heat dissipation system in space nuclear reactor power supply，a new structure of “contact-heat conduction” heat pipe radiator was designed，a heat transfer calculation model of “divided nodes-layered coupling” was put forward，and its radiation heat dissipation performance was calculated.Taking JIMO（Jupiter icy moon orbiter）space exploration mission as the background，the performance of whole heat dissipation system was analyzed and compared.The conclusions are as follows：in order to improve the heat dissipation performance of a single radiant panel and the whole system，besides increasing the inlet temperature of NaK78，the method of increasing the circulating mass flow of NaK78 can also be adopted.For a single radiant panel，when the mass flow of NaK78 is increased from 1kg/s to 10kg/s with a fixed heat dissipation area，the heat dissipation capacity of radiant panel can be increased by 14.14%;while for the whole system，when the mass flow of NaK78 is increased from 1kg/s to 10kg/s with a fixed heat dissipation capacity，the total area of radiant panel required can be reduced by 67.73%.The increase of cycle mass flow can be achieved by using the “series-parallel” combination of radiation plate connection.The JIMO heat dissipation system adopts a new type of radiating plate structure，which can reduce the total radiating area by 59.06% and the total mass of the radiating plate by 4.24%.The new type of radiating plate structure has high efficiency and lightweight.The conclusions are of guiding significance in the optimal design of heat pipe radiator of space reactor power system.

Key words: space nuclear reactor power, heat pipe radiant radiator, optimization design, coupled heat transfer calculation, performance analysis, comparative study