TN-68 DUAL PURPOSE CASK DESIGN

The TN-68 is an optimized, dual-purpose dry storage design which can be loaded in the spent fuel pool and transferred to the ISFSI for storage, or with impact limiters attached used as a transport packaging. The loaded cask weights about 115 US tons and has a capacity of 68 intact BWR fuel assemblies. This cask, the TN-68, is a longer, BWR fuel version of Transnuclear’s standard TN-32 Advanced Storage Cask design for PWR fuel. The design is based on the high capacity casks which Transnuclear has previously designed, licensed, fabricated, and delivered (the TN-BRP, TN-REG, TN-24P, TN-40, and TN-32). The TN-68 is very similar in design to the TN-40, a site-specific cask system which was developed and licensed for NMC’s Prairie Island Plant, and the TN-32, a generic PWR storage cask which was licensed for Surry and North sites Anna of Dominion. Several significant improvement in storage cask design have been incorporated into this dualpurpose cask system, providing the TN-68 system with the capital economics which have historically been available only with storage system employing concrete technology. At the same time, the highly regarded operational features of the TN-32 and TN-40 have been incorporated into the design, keeping operational costs and radiation exposure far below those of conventional concrete system that require welding of canister lids and transfer casks. These advantages have been achieved while ensuring that none of the features which enhance cask and operational economics would jeopardize designing the cask for transportability, a significant feature of the metal cask storage. The approach to the development of the TN-68 dual-purpose cask focused on the following major improvements over many current metal cask systems.