Evaluating the feasibility of new surveillance concept for Dry Storage System through CFD methodology

• Thermal hydraulic behavior of a 3-D dry cask under several off-normal conditions has been numerically investigated by ANSYS/FLUENT.
• The simulation methodology was fully validated by comparing the measured results of VSC-17.
• The results indicated that many design bases accidents can be early detected by the purposed surveillance method.
• A simply determine rule has been developed for future application for dry storage ​monitoring.

Since the Dry Storage System (DSS) has passed into a widespread middle-term storage method for Spent Nuclear Fuels (SNFs), the situation monitoring technology for a DSS should be further improved to ensure the reliability of DSS during storing time. However, a passive cooling mechanism with a full-sealed storage requirement causes that the internal situation cannot be directly monitored by thermocouples inserted into the DSS. In this study, a new surveillance method, therefore, has been proposed to overcome this problem. It can predict the DSS situation through measuring the temperature profile at the Transportable Storage Canister (TSC). A validated CFD methodology has been utilized to confirm the method through simulating the thermal characteristics of the ChinShan DSS (CSDSS). The major factors, such as the thermal loading, accident situation and flaw caused by penetrated hole probably, have been considered in this present work. The result shows that the above-mentioned issues would obviously affect the temperature profile on the TSC and can be identified via detecting the temperature profile difference on of TSC. These results confirm that the indirectly surveillance method has enough capability to replace the original monitored method and provide more system information of DSS vendor for middle-term storage.