Status of Boiler Effect for Safety-Related Gate Valves and Its Improvement

Based on international experimental and research results for Boiler Effect,this paper describes the analysis principle and method for Daya Bay Ling'ao nuclear power stations to confirm which gate valves are affected by boiler effect.Further analysis with PSA and detailed safety functions is to define finally RIS063/064VP and PTR022VB need to be modified.The solution avoiding Boiler Effect for RIS063/064VP is adding a bypass line with double-directional check valve,and drilling a hole on the upstream disk of PTR022VB is adopted.