DEVELOPMENT OF IN-SERVICE INSPECTION TECHNIQUES FOR NUCLEAR-POWER-PLANTS IN INDIA

The present status of in-service inspection (ISI) in the Indian nuclea r power plants using non-destructive testing (NDT) techniques such as eddy current testing (ECT), acoustic emission (AE) monitoring, ultraso nic testing (UT) is discussed Development of digital signal analysis t echniques that will lead to better analyses of the NDT data are highli ghted. ECT has been successfully developed to locate the garter spring s in the calandria/pressure tube assemblies of the pressurized heavy w ater reactors (PHWR) and the profiling of the gaps between the calandr ia and pressure tubes. It is now a standard ISI technique. AE has been successfully used to locate leakage paths in the end shields and cool ant tubes of PHWRs. Digital signal analysis has been used for enhanced sensitivity and better defect characterization in difficult to inspec t austenitic stainless steel weldment by UT Digital eddy current imped ance imaging has been applied to locate weld centreline in austenitic stainless steel weldments towards automated in-service inspection.