Year
2014
Abstract
Performing the different types of analyses required to account for the changing nuclear and mechanical characteristics of used nuclear fuel (UNF) over time, and understanding how these characteristics affect the different storage, transportation, and disposal options, can require many tools and types of data. To streamline analyses for the waste management system, a comprehensive, integrated data and analysis tool has been assembled—the UNF-Storage, Transportation & Disposal Analysis Resource and Data System (UNF-ST&DARDS). UNF-ST&DARDS provides a unified domestic UNF system database and integration with key analysis capabilities to support numerous US Department of Energy (DOE) waste management and fuel cycle–related objectives, as well as the foundation for tracking UNF from reactor power production through ultimate disposition. A unique, unprecedented capability within UNF-ST&DARDS is the automated performance of actual as-loaded, cask-specific evaluations. This capability enables quantification of realistic safety margins and conditions of existing dry cask storage systems and potential future cask systems as opposed to the bounding, highly conservative estimates typically used for licensing and initial cask loading. A key feature is the data relations defined within the database that allows the large number of inputs required to characterize the UNF for each respective site to be generated automatically. UNF-ST&DARDS currently includes five main types of data: 1) fuel assembly discharge information; 2) fuel assembly design data; 3) reactor-specific operation data; 4) cask design and loading data; and 5) infrastructure and logistics-related data to support systems analyses. The integrated analysis capabilities include assembly depletion and decay and cask criticality and shielding via the SCALE code system and cask thermal analysis via the COBRA-SFS code. This paper provides an overview of the system and selected cask-specific calculation results that demonstrate the large safety margins, as compared to regulatory guidance limits, in existing loaded UNF casks.