A Joint Approach for PWR Core Barrel Bolt and Weld Inspection

Abstract

The outer circumference of the core internals is formed by a cylinder-shaped shell, the corebarrel, which are welded together.The enclosed horizontal former plates are connected to the core barrel via support and/orclamping ripples and the support plates. Bolts connections are used to fasten the supportplates.In case the integrity of the barrel welds and of the barrel former bolts is not guaranteed, theentire structure of the core barrel would be jeopardized by the external forces which occuraccording to design and operation loads.It is, therefore, of importance to inspect the barrel former bolts and barrel welds with anon-destructive inspection method and to replace them in case of a failure. Because of thehigh radiation in this area, all work has to be done by remote controlled manipulators.The first inspection of core barrel bolts and welds was successfully conducted by the jointefforts of Kansai, MHI and ABB Reaktor. This result demonstrated the ability to inspectthe core barrel bolts and welds using manipulator system and UT technique.