Abstract: Heat storage system is one of the core systems in a CSP plant. During the commissioning，overhaul or under continuous poor weather conditions，storage tanks will encounter long-period shutdowns，resulting in thermal stratification which will affect the storage tank security. Intensifying the disturbance in storage tanks is the most effective means to eliminating the thermal stratification phenomenon，but there is little research on this method in storage tank design.The thermal stratification elimination realized by recirculation disturbance after the formation of thermal stratification in molten salt storage tanks was analyzed by CFD simulation. The results show that the molten salt recirculating inside the tanks can be fully mixed in 2.8 h when it is disturbed by a 100 kg/s flow. In a cold tank with a circulation pipe，it takes 3.1 h for mixing，and the maximum temperature difference of the molten salt in the storage tank drops to 14.5 ℃.Therefore，this flow can be regarded as the recirculating disturbance flow after thermal stratification in the operation phase of the project.

Key words: CSP, molten salt storage tank, thermal stratification, CFD, circulation pipe, heat storage system