Construction NDT and PSI for CPR1000 nuclear island main equipment

During pre-service inspection (PSI) of CPR1000 nuclear primary components, "unacceptable defect" was found in the welds which were complying with the requirements of nondestructive testing during construction. To solve the problem, the NDT requirements between construction and PSI have been analyzed, typical engineering cases have been also demonstrated, and the feasible reconciliation engineering solutions have been developed. On account of PSI being considered to act as a "zero point" for in-service inspection, the following view point is hence postulated that "suspected unacceptable defects" found during PSI, if possible, should be re-examined and evaluated in accordance with the testing method and acceptance criteria during construction. If the re-examination result meets the requirement, the welds with the above-mentioned defects should be categorized as acceptable.