Alternative Bag-out-bag materia

The United States Department of Energy, Manual, M441.1-1, Nuclear Material Packaging, provides detailed packaging requirements for protecting workers from exposure to nuclear materials stored outside of an approved engineered contamination barrier. The SAVY-4000 Series nuclear material packaging system is a DOE Manual 441.1-1 compliant storage system used at Los Alamos National Laboratory and across the DOE complex as the primary storage system for plutonium-containing materials. The Container Safety and Engineering Team at LANL considers internal packaging configurations as part of the safety system. Since 2015, the need to replace the suspended polyvinylchloride, or (sPVC), bag-out-bags has been made apparent, since these bags break down due to radiolysis. When the bag material deteriorates, it produces a corrosive gas known as HCl or hydrogen chloride gas and leaves behind the suspended plasticizer. The chlorine ions from HCl readily attacks the thin film passivation layer of the 316L stainless steel that makes up the SAVY-4000 nuclear material storage container’s inner surface. Over the course of SAVY4000 container surveillance operations, corrosion has been observed. While the SAVY-4000 container is continuing to perform its role robustly, the need for sPVC replacement remains a strategic goal. In 2018, a new polymer type was selected, and the first aromatic polyurethane ether, or (APU-e) bag-out-bag was manufactured by LANL. This bag did not have a filter installed and was formed by heat sealing the edges of the material together. This manufacturing method worked well for the first prototype test. APU-ether material does not produce any halogens as it breaks down over time. This means no chlorides, fluorides, etc., and no HCl gas generation. In 2022, the first real word aging experiments are coming out of the storage location for inspection and data collection. These experiments will continue until LANL is confident.