Report on the Regulators Experience of NDT Qualification for In-service Inspection of Nuclear Components

In November 1992, the Nuclear Regulators Working Group (NRWG) decided to set up a task force on qualification of non-destructive testing (NDT) systems for pre and in-service inspection of light water reactors. The first task was to agree on the philosophy and principles governing the qualification of techniques, equipment, software, procedures, and personnel for NDT to be used for the inspection of structural components that are important to safety in nuclear power plants; and to establish a common view on essential aspects of NDT qualifications. The first task, which also included a comparison of the common views of the European regulators with the qualification approach outlined in Appendix VIII to Section XI of the ASME Code, was completed in 1996. The result was published in the report ''Common position of European regulators on qualification of NDT systems for pre- and in-service inspection of light water reactor components''2. In parallel, the European nuclear power industries had set up a working group, the European Network for Inspection Qualification (ENIQ), to discuss and agree on how to perform inspection qualifications. In 1995, ENIQ finalized its first version of ''European methodology for qualification of non-destructive tests''3. A second version 4 was then published in 1997. This second version is in relatively close agreement with the principles given in the regulators common position document. With these two basic documents, a platform was established for the further development of qualification strategies in the European countries. The second task of the NRWG Task Force was to follow and evaluate the first ENIQ pilot study from a regulatory point of view. The objective of this pilot study was to explore ways of how to apply the European qualification methodology and to test its feasibility. The pilot study commenced late 1996 and was planned to be finalized a year later. Depending on unforeseen difficulties, the pilot study has been delayed several times, and first in 1999 the main part of the pilot study was completed. However, results from one important part of the pilot study are still missing. This relates to a planned comparison with results from an in-service inspection simulation on cracked piping parts that had been removed from a nuclear power plant. The objective of this third task was to compile a status report with information of actions taken, national developments, and experience since the publication of the common position document EUR 16802 in 1997, to follow the second ENIQ Pilot Study and evaluate the results from a regulatory point of view. The experience exchange started with a questionnaire that was sent to the present task force members 6 and to BCCN in France, who decided to not actively participate in the third task of the Task Force. The present report represents the work product of the experience exchange activities conducted by the Task Force. (author)