Evaluation of filtered containment venting system (FCVS) effects on severe accident of a WWER1000 plant

Abstract

To mitigate radioactive material release in nuclear facilities, some effective approaches have been suggested such as using filtered venting system (FCVS). For a nuclear containment, the FCVS reduces the overall environmental contamination. This work uses MELCOR for severe accident analysis, ORIGEN for isotope production and depletion calculation and HotSpot for health physics analysis to evaluate the progression of radionuclide release and containment structural stability during station blackout accident (SBO). In this analysis, the performance of a containment with a filter venting system is evaluated. The overall goals are assessment of FCVS effects on radionuclide release into environment and to evaluate containment integrity. In this research, three scenarios of radionuclide releases are considered. In the unmitigated case, no filtered venting system is employed. For the mitigated accident, a proper filtered venting path is considered for decontamination of the released material, and in the unfiltered case, there is a venting path but no filter is provided to absorb radionuclides. Also, the radiation dose produced after the radionuclide release based on the site meteorological condition is estimated. The main results include study of mass and decay heat of deposited radionuclides on filter and fission products release. This research proves, using FCVS saves public health and containment safety during SBO by mitigation mechanism.