Method and apparatus for suppressing water-solid over-pressurization of coolant in nuclear reactor power apparatus.

摘要

Malfunction under water-solid conditions responsive either to increase in mass flow or increase in heat flow into the reactor coolant is suppressed. A reactorcoolant relief valve (67) is opened for increase in mass influx if the rate of change of coolant pressure exceeds a setpoint during a predetermined interval, if, during this interval, the coolant temperature is less than a setpoint and if the level of the fluid in the pressurizer (15) is above a predetermined setpoint (water-solid state). The relief valve (67) is opened responsive to increased influx of heat to the coolant only while the coolant pump operates for a predetermined interval after it starts, if the level of the fluid in the pressurizer is above a setpoint, if either the difference between the temperature of the secondary fluid in the steam generator and the temperature of the coolant is above a predetermined setpoint or the difference between the temperature of the coolant and of the coolant in the loop seal is greater than a predetermined setpoint and if the coolant temperature is less than the setpoint.