Ten year RPV inspections experiences in a PWR in Spain: Improvements in the inner-radius inspection techniques

The in-service inspection of an RPV, performed in accordance with the scope and requirements of Section 11 of the ASME Code at the end of the ten year interval, is one of the most complicated ISI activities carried out. Special resources and tools are required for successful performance of this type of inspection: (1) preparation and planning; (2) mechanical scanner; (3) data acquisition and analysis system; and (4) ultrasonic techniques. This paper describes the most relevant issues relating to RPV inspection, along with the experience obtained during the inspection of the RPV of a 930 MW Spanish PWR plant in 1992. Special attention is paid to the improvements achieved with respect to inspection of the inner-radius areas of the primary nozzles.