Development of techniques for the pre service and in service inspection of nuclear power plant

Abstract

The paper describes the technique development for the non destructive examination (NDE) of critical areas of steam generator and pressurisers on a small pressurised water reactor (PWR) system. Problems arise during the ultrasonic inspection of thick section austenitic stainless steel welds, austenitic to ferritic transition welds and thermal sleeve forgings. Optimum conditions have been established to achieve a worthwhile examination in terms of test sensitivity, area coverage and analysis of test results. Similarly, optimum test conditions have been established for the eddy current examination of ligaments associated with headers and heater pockets. Representative test blocks containing artificial defects were used for both the ultrasonic and eddy current technique development trials. Inspections using purpose built manipulators were carried out due to access constraints and in order to minimise man radiation dose levels.