A numerical study of thermal behavior of CASTOR RBMK-1500 cask under fire conditions

Abstract

Casks are widely used for interim storage of spent nuclear fuel after its pre-storage in water pools. Interim storage of spent nuclear fuel is a very important part in the whole cycle of nuclear energy generation, so the casks must be designed according to relevant safety standards. Like criticality and doses, thermal safety is an important condition for spent nuclear fuel storage in a dry spent nuclear fuel storage facility and should be analyzed thoroughly. During the entire period of interim storage of spent nuclear fuel, normal operation and emergency situations should be investigated. Analysis of various accident scenarios is one of the means to prevent damage of storage casks and spent nuclear fuel. There are many publications on thermal cask behavior during normal operation conditions, yet publications on cask behavior during accidents are rather limited. There are a few publications presenting fire impact analysis of thermal behavior of casks during transportation. Therefore, this paper presents a numerical study that has been performed to evaluate thermal behavior of a cask under fire condition loaded with spent nuclear fuel stored in an open type dry storage facility pre-stored in a water pool for five years. Thermal performance of a 2D vertical CASTOR RBMK-1500 cask under such conditions (steady-state, fire, post-fire) has been numerically studied by using the ANSYS Fluent code. Also, a local sensitivity analysis of parameters that mostly influence the cask’s temperature was performed.