Repair of End Shield of Pressurized Heavy Water Reactor

Abstract

Rajasthan Atomic Power Station (RAPS) has two units of 220 MWe Pressurised Heavy Water type reactors. Each reactor has 306 fuel channel assemblies which are designed to permit their replacement. In the first unit of RAPS, during a reactor shut down, it was observed that cooling water (light water) was leaking from one of the end shields. The lattice locations which were the sites of leakage were identified and the concerned channels, three in number, were removed. Inspection and non-destructive examination indicated that the leakage was occurring from the inaccessible side of the end shield. Remote handling tools were developed for removal of the coolant channels and lattice tubes. Repair of leak was carried out by mechanical gasketing arrangement using indium metal as the sealing gasket material. This paper briefly describes the activities leading to successful repair of the component.