A spectrum of different break sizes

A spectrum of different break sizes at cold leg along with SBO are studied to understand the progression of the accident. It is observed that hydrogen generation is maximum for small break LOCA with HA injection and corium mass generation is maximum for large break LOCA without HA. Ejection of melt from the reactor vessel is found to be at atmospheric pressure except a slightly higher pressure melt ejection is observed for small break LOCA with HA injection. RCS is found to arrest majority of semi volatile and volatile fission products and acts like a filter thus reducing the load of filters in the containment.The calculation results are used to evaluate the SAMG recommendations and it is found for in-core injection pumps are required with minimum head of 4.06 MPa, which can be managed by making available the high pressure safety injection pumps with mobile diesel generator. Overall the time margin available to switch over from EOP to SAMG for low pressure event is assessed. The time margin available to activate the in-core injection pump is found to be much smaller with marginal core damage for large break LOCA as compared to sufficient time margin for medium and small break LOCA.