Advances in inservice inspection of the Winfrith steam generating heavy water reactor

The inservice inspection of the Winfrith steam generating heavy water reactor was outlined in a presentation to the 1975 BNES symposium on reactor inspection technology. This paper describes advances made in inspection techniques since 1975 in the fields of pressure tube and steam drum inspection. Ultrasonic and eddy current techniques and equipment are described which have been developed for pressure tube inspection and applied to the in-reactor examination of 21 pressure tubes between 1976 and 1980. Attention is drawn to the influence of the reactor environment on the inspection techniques, in particular the effect of corrosion layers on the bore of the pressure tubes. The results of both the in-reactor inspections and supporting laboratory development studies are reported. No significant defects have been detected in the 21 pressure tubes inspected. The paper also describes automatic manipulators obtained and commissioned in 1979 and their application to the inspection of steam drum partial penetration welds in 1980. (author)