Fast Diagnosis and Treatment of Cracklife Defect Injuriousness in Nuclear Power Plant Equipment

Increasingly stringent safety requirements governing the nuclear industry have made it essential to gain in-depth knowledge of the injuriousness of cracking phenomena in auxiliary and secondary nuclear power plant systems, and to devise methods of rapidly evaluating potentially injurious flaws. The defect injuriousness diagnosis and treatment package (DIDTP) was developed by Framatome, a French-based PWR builder, with this goal in mind. A general description of the DIDTP, which is made up of tables and nomographs illustrating the injuriousness of flaws liable to be encountered in the most severely loaded regins of plant systems is given. The basic principles underlying the DIDTP, together with computational methods and application procedure, are detailed. Two practical examples illustrating the use of the diagnostic system, one applied to the main steam line, the other to gate valve wedges are presented. The types of results obtained and the usefulness of the system as both a treatment and a diagnostic tool are explored. 17 ref.--AA