MELCOR DEC-B transients in a generic integral pressurized water reactor

Within the framework of the Euratom project SASPAM-SA Work packages 2 and 5, a MELCOR input deck for a generic integral Pressurized Water Reactor (iPWR) has been developed. The generic Design 2 is an iPWR, characterized by electric power of 300 MWe, a dry containment and protected by passive safety systems. Three main Design Extended Conditions were considered, all initiating from the rupture of a Direct Vessel Injection line, causing a small break LOCA. The investigations suggested that the scenario postulate different passive systems unavailability, to investigate MELCOR capability to simulate severe accident conditions in iPWR, which is the main aim of the SASPAM-SA project. The MELCOR input deck has been developed by the Sapienza University of Rome (DIEE, NERG research group) according to best practices. The results of the analysis demonstrate that MELCOR can qualitatively replicate the expected dominant phenomena that drive the severe accident sequences. In particular, an accurate evaluation of the containment response and the adequacy of the Filtered Containment Venting System in these scenarios was also investigated.