Regulatory Perspective on Transportation of High Burnup Spent Fuel

To successfully certify high burnup (i.e., >45 GWD/MTU) spent fuel (HBF) for transportation, information that demonstrates reasonable assurance in complying with the regulatory requirements of Part 71 in Title 10 of the Code of Federal Regulations (10 CFR Part 71) is required. HBF is susceptible to hydride reorientation which may occur due to elevated cladding temperature during loading, draining, and drying and subsequent cooling during transport. The hydrides reorienting and precipitating from circumferential to radial directions could affect the fuel cladding mechanical properties.On March 5, 2015, the NRC issued a draft Regulatory Issue Summary (RIS), “Considerations in Licensing High Burnup Spent Fuel in Dry Storage and Transportation.” As part of the RIS, potential licensing approaches were provided for certifying the transportation of HBF. These approaches consider certifying transportation packages where fuel is being shipped from a spent fuel pool, from a dry storage cask, or placed in damaged fuel cans prior to shipping. To develop these approaches, the U.S. Nuclear Regulatory Commission (NRC) is working with Oak Ridge National Laboratory and Argonne National Laboratory to obtain data on HBF cladding behavior through vibration tests and bend tests. The NRC staff has also completed the first phase of its research with Oak Ridge National Laboratory that provides data related to the behavior of HBF in transportation. NUREG/CR-7198, “Mechanical Fatigue Testing of High-Burnup Fuel for Transportation Applications,” published in May 2015 (ADAMS Accession No. ML15139A389) provides a benchmarking of the behavior of HBF without hydride reorientation. NUREG/CR-7203, “A Quantitative Impact Assessment of Hypothetical Spent Fuel Reconfiguration in Spent Fuel Storage Casks and Transportation Packages,” published in September 2015 (ADAMS Accession No. ML15266A413), provides a conservative consequence analysis assuming a full range of fuel failure. This paper describes the various technical approaches in certifying transportation packages for HBF.