Aging Management Applied to Storage of Bulk Ion Exchange Resin in Epoxy Coated Carbon Steel Containers

Abstract

Ontario Power Generation (OPG) began in-ground storage of spent ion exchange resins in the 1980s using epoxy coated carbon steel containers. In 2001, a sequence of aging evaluation activities based on EPRI guidelines was used to assess the current conditions of the stored containers. The evaluation concluded that the containers (also known as resin liners) may fail during the 50 years interim storage period due to fabrication defects and the storage environment. Risks to container integrity were then assessed through field activities which included ultrasonic measurements of the container wall thinning and characterization studies of the waste resins. While results confirmed that containment had not been breached and no resin leakage from the containers was detected, localized wall thinning and pits especially on the inner surfaces of the resin liner, were evident. The carbon steel liners were replaced by stainless steel 316L liners, during 2003, to provide enhanced resistance to pitting corrosion. A plan to “overpack” the carbon steel liners in stainless steel overpacks has been developed. Overall, the aging management approach applied has been effective in assessing age related risks of the critical systems, structures, equipment and components (SSEC) for resin storage, and defining the appropriate remediation strategy.