The Sensitivity of the Addition of Low-Low Pressurizer Pressure in Coincidence With High Containment Pressure on M310 Type Nuclear Power Plant

Due to the new security system that the operator intervention is assumed to occur in 20 minutes is not acceptable, for the current M310 type nuclear power plant. The loss of coolant accident with Intermediate breaks in primary loop is the only one of design basis accident which need operator action in 20 minutes. For certain size break, the consequences are very sensitive to the pump stop time. According to deterministic analysis that for a certain size break, if stop the pump in 20 minutes after accident, the peak cladding temperature will exceed the limit value of 1204°C. Therefore, it is necessary to add low-low pressurizer pressure in coincidence with high containment pressure signal to stop pump automatically on M310 type nuclear power plant.