Snubber Reliability Improvement Study. Final Report

摘要

As evidenced by the many problems documented since 1973, there has been concern for the reliability of piping system snubbers. Reliability can be improved when the recommendations of this report are followed; these recommendations were developed as a result of investigations of the problems. Hydraulic fluid leakage was first identified by the NRC as a widespread problem but has been substantially reduced by new seal materials. A later problem, failure of operability tests, is now the leading cause of snubber failure. The failure rate due to functional test failures can often be reduced if the acceptance criteria used for the test are relaxed without compromising the technical integrity of the snubber or the restraint function for which it is installed. The acceptance criteria can often be relaxed, but a thorough understanding of major snubber parameters must first be gained. A discussion of each snubber parameter is provided. Additional recommendations are made for qualification and acceptance testing, environmental testing, and maintenance practices. (ERA citation 07:043328)