Research on the key design of emergency core cooling scheme for Tsinghua high flux reactor

Abstract

This paper introduces the updated emergency core cooling scheme for Tsinghua High Flux Reactor. The corresponding Relap5 model is established and key designs are studied by simulating the corresponding loss-of-coolant accidents. These key designs specifically involve ACC internal pressure, ACC coolant temperature, ACC liquid fraction, ACC location, emergency pumps, check valves at pressure vessel inlets, the design of pressure vessel outlet, connection between the dry pool and the reactor pool, and operation pressure. Through analysis, some general conclusions are obtained, which can be used to guide the design of emergency core cooling system in the near future. Critical heat flux is predicted by Sudo correlations during loss-of-coolant accidents. According to minimum departure from nucleate boiling ratio, core safety margin is evaluated. By studying these key designs, the current scheme can be better understood and more safety margins can be found.