Safe Shutdown/Appendix R Analysis
EPM has been providing Appendix R/safe shutdown-related engineering services since it was established in 1980. EPM has performed Appendix R review and reanalysis of safe shutdown capabilities for one-third of all U.S. nuclear power plants and for all but four units in Canada. As a result, over 400 exemption requests have been written in the U.S. Of these 400 exemption requests, over 90% were approved.
Given our extensive experience in this area, EPM pioneered a risk-informed/performance-based methodology for safe shutdown and fire hazards analyses when we were tasked with the challenge of addressing these issues for nuclear power plants in Canada. Based on our experience with U.S. plants and the requirements of 10 CFR 50 Appendix R, EPM knew that prescriptive methods would not be practical due to significant lack of separation and physical barriers. As such, we decided to use the techniques that were being developed in NFPA 805 and apply them to the CANDU reactors. EPM’s methodology is centered on identification of an analysis of realistic fire scenarios rather than postulating an “all consuming fire.” EPM’s approach is based on recognized industry methods and techniques for risk assessment and simplified fire modeling.
EPM has performed fire safe shutdown analyses for a variety of reactor types including BWR, PWR, CANDU, SVVR, and RBMK reactors.