New Concepts, Requirements and Methods Concerning the Periodic Inspection of the Candu Fuel Channels

Abstract

Periodic inspection of fuel channels is essential for a proper assessment of the structural integrity of these vital components of the reactor. The development of wet channel technologies for non-destructive examination (NDE) of pressure tubes and the high technical performance and reliability of the CIGAR equipment have led, in less than 10 years, to the accumulation of a very significant volume of data concerning the flaw mechanisms and structural behaviour of the CANDU fuel channels. On this basis, a new form of the CAN/CSA-N285.4 Standard for Periodic Inspection of CANDU Nuclear Power Plant components was elaborated, introducing new concepts and requirements, in accord with the powerful NDE methods now available. This paper presents these concepts and requirements, and discuss- es the NDE methods, presently used or under development, to satisfy these requirements. Specific features regarding the fuel channel inspections of Cernavoda NGS Unit 1 are also discussed.