Pressure Behavior of CANDU Reactor Building and Estimation for Safe Depressurization during Station Blackout Accident

After the Fukushima nuclear power plant accidents, it has been one of the key issues to maintain reactor building integrity as a fission product barrier. Currently, we can use active containment heat removal system or depressurization strategy through the filtered venting system for that purpose. In the case of SBO accidents, active components including pumps cannot be used. Therefore, in provision of most severe cases of the accident progression, we need to have venting strategy to protect reactor building integrity. In this paper, we briefly discuss the results of Wolsong CANDU PSA and severe accident sequence analysis and present the results of a parametric study on the venting flow rate for successful depressurization. Filtering or scrubbing of radioactive material for the process is not treated in this paper