Thermal analysis of CASTOR RBMK-1500 casks during long-term storage of spent nuclear fuel

In this paper, thermal analysis of German CASTOR RBMK-1500 casks for long-term (up to 300 years) storage of spent nuclear fuel at the Ignalina Nuclear Power Plant was performed. The numerical modeling code ALGOR (USA) which allows modeling temperature and heat flux distributions inside a cask (in fuel load) and in a cask body, was used. The modeling was performed for a cask in an open storage facility in summer and winter conditions. A detailed analysis was performed including previous results about casks with just loaded fuel (pre-stored in water pools for 5 years) and after 50 years of interim cask storage. Also, a local sensitivity analysis of parameters that mostly influence the temperature distribution was performed.