Failure experience as a tool for evaluation of nuclear structures

Abstract

High reliability in nuclear structures is attainable only because previous failure experience with comparable installations can be factored into structural evaluations in such a way that unsatisfactory experience is forestalled. The use of corrective techniques to eliminate in-service faults in consumer products as a means of improving the characteristics of future products is a well-known quality control principle. This principle is only applicable to nuclear structures if the nature and causes of structural failure are fully understood. The development of some well-established structural practices that evolved through the correlation of failure experience with structural evaluation methods is discussed in this paper. Attention is then directed to the use of analogous experience in nuclear applications as an approach to the attainment of suitable structural failure characteristics. A recognized shortcoming in the use of failure experience as a basis for judging structural adequacy is the paucity of statistical data to support the evaluation process. The use of calculational and experimental methods that simulate failure characteristics as a substitute for real experience is a valuable adjunct to such statistical data. The correlation between actual failure experience and simulation techniques is set forth as a crucial feature of nuclear structural evaluations with careful interpretation of actual failure causes and effects as the prime control on structural evaluation methods.