Statistical Performance Evaluation of Spring Operated Pressure Relief Valve Reliability Improvements 2004 to 2014

The United States Department of Energy’s Savannah River Site (SRS) in Aiken, South Carolina, is dedicated to promoting site-level risk-based inspection (RBI) practices in order to maintain a safe and productive work environment. Inspecting component parts of operational systems, such as pressure relief valves (PRVs), is a vital part of SRS’s safe operating envelope. This paper is a continuation of a SRS program to minimize the risks associated with PRV failures. Spring operated pressure relief valve (SOPRV) test data accumulated over the past ten years resulted in over 11,000 proof tests of both new and used valves. Improved performance is seen for air service valves resulting from changes to the maintenance program. Although, statistically significant improvement was not seen for liquid, gas, or steam service valves, analysis shows that the overall probability of failure on demand is trending down. Current SRS practices are reviewed and the reasons for improved performance are explored.