Research on Severe Accident Mitigation Strategy of Injecting Into the OTSG of ACP100

The China multipurpose module small reactor named ACP100 is developed by the China National Nuclear Corporation (CNNC). The severe accident management guidelines (SAMGs) of ACP100 reactor is necessary to be developed to mitigate the severe accident induced by in the multi-cause extreme conditions. Inject into the steam generators (SGs) is one of the most significant strategies, this strategy aims at protecting the SGs tubes from creep rupture, removing the heat from the reactor coolant system (RCS) and depressurizing the RCS. The entry condition of the severe accident guideline of injecting into the SGs, as usual, is low SG Water level in the most of the present pressurized water reactors that adopt the inverted U-tubes SGs. The integral reactor of ACP100 adopts the design of annular tube once-through SGs. In the normal conditions, the secondary side of the OTSGs is operating in a given steady pressure, any water level measure tool is impossibly set in the OTSGs. Therefore, on the basis of the design features of ACP100, the strategy of injecting into the OTSG at severe accident is studied, the potential entry condition of the corresponding guideline is discussed. And the validity and feasibility of the strategy is validated by the analysis of the integral systems analysis code.