Modelling and simulation of containment retention factor for can-type containment

Abstract

Severe accidents cause the failure of fission product barriers and allow the fission products to escape into the environment. The containment is the last barrier for fission products. Thus, containment spray system, heat removal system, recirculation filtration system, Containment Filtered Venting System (CFVS) and containment exhaust filtration system are installed in the containment to mitigate the exposure to environment. In this work, modelling and simulation of the Containment Retention Factor (CRF) have been carried out for the can-type PWR containment considering a 1000 MWe PWR. Computational modelling and simulation have been carried out by developing a kinetic code in MATLAB, which uses the containment-specific activity available after the accident. The kinetic dependency of CRF in terms of containment filtration systems and spray system with caustic and boric acid spray has been carried out. For noble gases, iodine and aerosols, the CRF increases with the increase in exhaust rate, while with the containment spray flow rate, the CRF for iodine first increases and then starts reducing with significant magnitude.