A study of large break LOCA in the AP1000 reactor containment

In this paper, one of the most dangerous accidents in reactor containments known as Loss of Coolant Accident (LOCA) in its worst condition called large LOCA has been modelled. The specific type of large LOCA is DECL (Double Ended Cold Leg) break which means a total guillotine type of break in cold leg pipe. When ‘LOCA’ occurs, the coolant itself is lost, then in this case that happens with pipe break or any kind of losing, the danger of core melting is possible. This modelling is performed in two volumes method in AP1000 reactor which is one of the most sophisticated safe reactors that has ever been built. Its safety systems provide a large variety of safety margins. One of the most important safety features in AP1000 is its passivity. This advantage provides many simplifications to enhance the safety, reliability, construction, operation, maintenance, investment, protection and plant costs. Therefore, it is worthwhile and makes sense to perform the analysis of a most dangerous accident in one of the most secure reactors. The modelling software applied in our analysis is MATLAB, and the results are compared with the AP1000 safety, security and environmental reports.

► In this paper, LOCA has been modeled in the AP1000 Reactor Containment.
► The specific type of LOCA is DECL (Double Ended Cold Leg) break.
►  We have used equations of Mass, Energy and Momentum conservation for this modelling.
► The results are compared with the AP1000 safety reports.