Calandria Tube Replacement in CANDU 2A-I Reactors

Abstract

This paper presents the procedure, planning and tooling required for calandria tube removal in CANDU reactors, and in particular the actual removal of the NO6 calandria tube in Bruce Unit 2. Only four calandria tubes have ever been replaced in operational CANDU reactors. This is in contrast with close to 1,000 pressure tubes removed from 1967 until 1987. Tooling, equipment and procedure refinement resulted in improvements to single calandria tube replacement operations. Further improvements are expected from the ongoing studies for large scale calandria tube replacement programs.