Study on the minimum number of SRVs required for emergency depressurization in EOP of BWR power plants

The minimum number of safety/relief valves (SRVs) required for emergency depressurization (MNSRED) is an important reactor pressure vessel (RPV) parameter described in the appendix C of BWR Owners’ Group, Emergency Procedure Guidelines and Severe Accident Guidelines (BWROG, EPG/SAGs). It is directly related to the emergency depressurization if there are less SRVs available. MNSRED is always coupled with decay heat removal pressure (DHRP) in emergency depressurization. DHRP is used as the depressurization low-pressure end to ensure the decay heat can be removed.