Evaluation of Sampling Plans for In-Service Inspection of Steam Generator Tubes. Modeling of Eddy-Current Reliability Data, Analytical Evaluations, and Initial Monte Carlo Simulations.

摘要

The Steam Generator Group Project was a multi-task effort using the retired-from-service Surry 2A pressurized water reactor steam generator as a test bed to investigate the reliability and effectiveness of in-service nondestructive eddy-current (EC) inspection equipment and procedures. The information that was developed provided the technical basis for recommendations for improved in-service inspection methods and tube plugging criteria for steam generators. Volume 1 of two volumes documents the results of analyses performed to evaluate and compare candidate sampling/inspection schemes for in-service inspection of steam generator tubes. The estimated EC inspection reliability determined from round robin examination of the Surry generator was used to guide the selection of input parameters for analyses. Analytical evaluations of candidate sampling/inspection schemes based on the ranges of probability of detection and probability of exceeding the EC plugging limit, as estimated from the round robin data, are described. Monte Carlo simulation analyses designed to supplement the analytical results and test key assumptions are presented. Finally, conclusions and recommendations for further study are presented.