Document: NUREG-0800
Document ID: 4d7d277e-c006-45d6-94df-c84845dd68d0
Document Type: srp
Title: INADVERTENT OPENING OF A PWR PRESSURIZER PRESSURE RELIEF VALVE OR A BWR
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350144.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.6.1
CFR Part: 
CFR Title: 

Content:
nt pressure, pressure.rellef valve flow rate, and flow rate from the reactor coolant system to the containment system (if applicable) are reviewed. Values of the more important of these parameters for the transient caused by the inadvertent pressure refief valve opening are compared to those predicted for other similar plants to confirm that they are within the expected range. Upon request from the RSB reviewer, other branches will provide input for the areas of review stated in subsection I of this SRP section. The RSB reviewer obtains and uses the input requested as required to assure that the review procedure is complete. IV. EVALUATION FINDINGS The reviewer verifies that the SAR contains sufficient information and that the review supports the following kinds of statements and conclusions, which should be included in the staff's safety evaluation report (SER): A number of plant transients can result in a decrease of reactor coolant inventory. Those that might be expected to occur with moderate frequency are Pressure relief valve openings, minor primary pipe breaks, and (in BWRs) loss of feedwater.* All of these postulated transients have been reviewed. It was found that the most limiting in regard to core thermal margins and pressure within the reactor coolant and main steam systems was the transient. This transient was evaluated by the applicant using a mathematical model that had been previously reviewed and found acceptable by the staff. The parameters used as input to this model were reviewed and found to be suitably conservative. The results of the analysis of the transient showed that the specified acceptable fuel design limits were maintained by ensuring that the minimum departure from nucleate boiling ratio (DNBR)** did not decrease below and that the maximum pressure within the reactor coolant and main steam systems did not exceed 110% of the design pressures. The staff concludes that the plant design in regards to transients that are expected to occur