Design and characteristics analysis of various residual heat removal schemes and shutdown control strategies for helium-xenon cooled reactor system

As one of the fourth generation advanced reactor technologies, helium-xenon cooled reactor Brayton cycle system has excellent application prospects in small nuclear power plants due to its remarkable advantages of small size, light weight, high stability, simple structure and rapid construction. The design and characteristic research of residual heat removal scheme and shutdown control strategy is of great significance to ensure the safe shutdown of reactor system and continuous removal of residual heat from reactor core. Therefore, this paper designs two kinds of residual heat removal schemes for the active and passive residual heat removal methods respectively, and designs the corresponding shutdown control strategy for each kind of residual heat removal schemes. Based on the self-developed system transient analysis program Bresa, the system shutdown transient process under four schemes and strategies is simulated and the transient characteristics are analyzed. Finally, the comparative analysis of various schemes and strategies is carried out. The results show that under the four schemes and strategies, the transient response changes of reactor system key parameters during shutdown reflect that the reactor system can shut down safely and continuously remove residual heat, which verifies the feasibility of the four schemes and strategies. After the evaluation of the control strategy complexity, actual operation difficulty, system size, security, economy and accident hazard level. For the active residual heat removal method, scheme 2 is the best scheme and is shown in fig. 1 (b). For the passive residual heat removal method, scheme 1 is the best scheme and is shown in fig. 2 (a). The relevant research results provide theoretical reference and support for the design and research of residual heat removal scheme and shutdown control strategy of helium-xenon cooled reactor Brayton cycle system.