Research and application of CANDU6 heavy water reactor spent fuel dry storage technical optimization

The Third Qinshan Nuclear Power Co., Ltd. (TQNPC) has established the first dry spent fuel storage facility (QM-400 module) off the reactor in China, adopting the early gas cooled storage module technology in Canada. The design scheme is too conservative, and the heat shields arranged inside the module may fall and block the air inlets, this case would lead to accidents. Therefore, this paper optimizes the QM-400 module to eliminate its internal heat shields. In this paper, the model of passive air cooling and concrete solid heat conduction of QM-400 module is established by one-dimensional fluid transient program CATHENA. Based on the test data, the model is modified, and the overall safety analysis of QM-400 module after the removal of the internal heat shields is completed. At the same time, the CFD program of three-dimensional fluid calculation is used to model the QM-400 module independently, and the independent checking calculation of CATHENA program is realized. The technical optimization of eliminating the internal heat shields of QM-400 module has been applied to the design and construction of the subsequent spent fuel dry storage module of TQNPC, this technical improves the safety performance of the spent fuel storage facilities and significantly reduces the construction cost. (authors)