Year
2003
Abstract
The issue of safeguards and security of spent nuclear fuel (SNF) is of increased international concern. Recent technical developments may enable construction of a multi-functional cermet cask with enhanced security features. The multi-functional cask is loaded with SNF at the reactor and then used for SNF storage, transport, and disposal. The SNF is handled only once—when the cask is loaded—minimizing handling of SNF and allowing the cask to be welded shut after loading. The cask weight (70 to 100 tons) and the sealing system act as major physical barriers to theft or diversion. The size of the cask allows surveillance from orbit, and transponders can be attached to each cask to confirm that no tampering has occurred. The viability of a multi-functional cask depends upon meeting the multiple requirements for storage, transport, and disposal. This objective is accomplished by using casks constructed of cermets. The cermet cask contains various ceramics embedded in a continuous steel matrix. Depleted uranium dioxide (DUO2) in the cermet maximizes shielding efficiency, which maximizes cask capacity (i.e., the number of fuel assemblies per cask) and improves the economics. Hard ceramics (such as Al2O3, which is used in traditional cermet armor) are added to the cermet to maximize resistance to military weapons, cutting tools, and other devices. A new cermet fabrication method (patents applied for) creates the potential to produce a low-cost thick-walled variable-composition cermet cask. The variable composition allows different ceramics to be located in different locations within the cask body and thus maximize both economics and assault resistance. The combination of the new cermet cask fabrication technology and the systems design creates the potential for an SNF super cask. This paper describes the basis for the system, the cask, and the enabling fabrication technologies.