In order to solve the problem that Qinshan No.3 Nuclear Power Co., Ltd. (hereinafter referred to as TQNPC) plans to extend the service life of the nuclear reactor, resulting in the increase of spent fuel and insufficient capacity of existing spent fuel dry storage module, an intensive spent fuel dry storage facility (M1 spent fuel storage module) is developed based on the original No.1~6 (QM-400) spent fuel storage modules. Compared with QM-400 spent fuel storage module, M1 spent fuel storage module has larger storage capacity and higher energy density. In order to demonstrate the thermal safety of M1 spent fuel storage module, RELAP5/MOD3 program is used to establish the thermal analysis model of M1 spent fuel storage module according to the conservative initial assumptions. The temperature of each part of the module under normal operation and accident analysis under extreme weather conditions is calculated. The 3D computational fluid dynamics (CFD) program is used to verify the result of RELAP5 program. The thermal safety of M1 spent fuel storage module is verified according to the calculation results from RELAP5 and CFD programs. Copyright ©2022 Nuclear Power Engineering. All rights reserved.