21PF OVERPACK PROBLEMS

The 21PF overpack has had severe metal corrosion and stress corrosion cracking (SCC) for many years. The U.S. Department of Transportation (DOT) and the U.S. Nuclear Regulatory Commission (NRC) have disallowed the use of overpacks containing high chloride foam. Corrosion and SCC of 21PF overpacks have been documented and papers have been presented at conferences about these issues. Regulatory agencies have restricted 21PF overpack use and have requested data to determine if phenolic foam overpacks not meeting original design specifications will be authorized for continued use. This paper details some of the problems experienced by users and relates actions of the DOT and NRC concerning these packages. Industry is working to correct deficiencies, but if they are not successful, the entire uranium enrichment industry will be severely impacted.