Review on Reactor Coolant Pumps Trip Criteria After Small Break LOCA in PWR

Abstract

The post-accident operation status of reactor coolant pumps (RCP) play an important rule in accident mitigation, especially for the loss of coolant accident (LOCA), the prolonged RCP operation after medium and small LOCA will aggravate the deterioration process of RCS water inventory. This paper first analyzes the adverse influence of delayed trip of RCPs after medium and small break on RCS, then the principle of determining the trip criteria of RCPs is suggested, the trip criteria of RCPs from the worldwide nuclear steam supply system venders are investigated and summarized. From the perspective of prolonging the operator ‘s non-intervention time, reasonable measures to alleviate the consequences of medium and small LOCA, such as the RCP automatic trip logic and RCS fast depressurization by cooling, etc., are of great significance to improving the safety level of the plant.