Thermal Analysis of Concrete Cask in Normal and Accident Conditions

Concrete cask used in the storage of spent nuclear fuel must be designed, erected and utilized safely according to appropriate standards and regulations. In this paper, a three dimensional finite element model simulating a quarter of concrete cask is established using the commercial Computational Fluid Dynamic (CFD) Code ANSYS to ensure that the system will satisfy the safety requirements. The analysis and the temperature distribution due to the air flow are analyzed in normal ambient temperature and at temperature of 800 degree C representing a fire. accident condition for a duration of 30 minutes Calculation results in the annulus region of air in normal condition are compared with test results for validation. Thermal analysis results in fire condition indicate small variation of temperature in the Stainless steel canister with a maximum variation relative to normal condition of 5.7 degree K and large variation in temperature distribution in the annulus region of air with a maximum variation from normal condition of 37 degree K. This variation will not exceed the safety limits