COBRA-SFS Transportation Template Development for UNF-STADARDS

Disclaimer: This is a technical abstract that does not take into account the contractual limitations underthe Standard Contract for Disposal of Spent Nuclear Fuel (SNF) and/or High-Level Radioactive Waste(HLW) (Standard Contract) (10 CFR Part 961). Under the provisions of the Standard Contract, the U.S.Department of Energy (DOE) does not consider SNF in multi-assembly canisters to be an acceptablewaste form, absent a mutually agreed to contract amendment. To the extent discussions orrecommendations in this abstract conflict with the provisions of the Standard Contract, the StandardContract provisions prevail.In the United States there are over 2500 loaded spent fuel dry storage systems in operation. Eventuallythe canisters stored in these systems will need to be transported, potentially multiple times to interimstorage or disposal sites. With this kind of spent fuel transportation volume an exceptional amount ofplanning is needed to make sure that the canisters, fuel, and transportation cask meet thermal,shielding and criticality requirements. DOE has developed UNF-ST&DARDS to help perform this task.Through the use of multiple analysis codes and a large amount of data collection this tool has thecapability to ascertain the site specific conditions of fuel around the country and whether or not it istransportable. COBRA-SFS is the thermal analysis tool used to develop modeling templates for this task.Thermal conditions are critical because most systems have a lower design basis heat load for transportthan for storage. This paper details the recent thermal template development work conducted at PNNLand the template development process needed to have both general and site specific template models.