Numerical Simulation and Analysis for the Decay Heat Exchanger of China Prototype Fast Reactor

Decay heat exchanger (DHX) is an essential piece of equipment of the decay heat removal system (DHRS) in a pool-type sodium-cooled fast reactor. The main function of DHX is to transfer heat from primary circuit fluid (liquid sodium) to secondary circuit fluid (liquid sodium) of DHRS, which can reduce the high temperature caused by decay heat in the reactor core. In this paper, CFD method was used to simulate the statistic three-dimensional flow field of DHX which is used in China Prototype Fast Reactor under several different operating conditions. The numerical results under rated operating conditions were compared with the design values and the comparison was fit in with expectation, which demonstrated the validity of the numerical model. The study of the flow field of DHX under designed operating conditions was conducted to obtain the heat transfer features and the flow characteristics. The results show that the design of DHX in China Prototype Fast Reactor is sufficient to the purpose to timely bring the decay heat out of the reactor core and DHX meets the safety design requirements from the perspective of heat transfer. The work in this paper provided references for further design improvement of the DHX in a pool-type sodium-cooled fast reactor. (paper)