Towards establishing a service life for the SAVY-4000 nuclear material
storage container at Los Alamos National Laboratory

The SAVY-4000 nuclear material storage container has been in use at Los Alamos National Laboratory (LANL) as a DOE Manual 441.1-1 compliant container since 2014. The most common packaging configuration for storage containers involves a nested configuration of a metal inner container, bag-out bag, and SAVY-4000 outer container. Polyvinyl chloride (PVC) bag-out bags are used to control radiological contamination when the inner container is bagged out of the glovebox. This generally prevents contamination of the inside of the SAVY-4000 container and allows them to be re-used. In the past few years, however, corrosion of the SAVY-4000 has been observed through annual container surveillance efforts. One source of this corrosion arises from the degradation of the bag-out bag resulting from thermal and radiolytic degradation pathways. The subsequent production and release of hydrogen chloride gas corrodes the stainless-steel container wall. Corrosion rates of the 316L stainless steel and, consequently, the service life of the SAVY-4000 depend heavily on this bag-out bag degradation rate, in addition to other environmental and packaging factors, such as temperature and relative humidity. Our recent efforts to establish a service life for the SAVY-4000 comprises three unique activities: 1) Surveillance of nuclear material storage containers including the SAVY-4000 and its predecessor containers with longer service lives, 2) systematic corrosion experiments on coupons to understand controlling mechanisms of corrosion, and 3) accelerated aging experiments to establish corrosion thresholds as related to container performance. Details of the projected path toward lifetime evaluation and possible extension are highlighted, as well as an overview of the latest corrosion analysis efforts.