Steam generator aging in CANDUs: 30 years or operation and R and D

Thirty years of operational experience has now been obtained for CANDU steam generators (SGs) that have been tubed with a variety of materials including Alloy 400, Alloy 600, and Alloy 800. A number of different SG degradation mechanisms have been experienced, many of which were neither anticipated by designers nor expected by operators. This paper gives a brief overview of the historical evolution of the degradation mechanisms and highlights the key factors responsible for the degradation. It also discusses the R and D response, the industry actions, and a projection of operating requirements for the next 30 years of operation. (author)