Year
2010
Abstract
The interim storage package for plutonium used at the Atomic Weapons Establishment (AWE) contains polyvinyl chloride (PVC) bags as part of a multilayer containment system. It is known that PVC undergoes thermal degradation at temperatures above 100oC, producing flammable and corrosive gases which have the potential to damage the integrity of the package. Although the permitted payload for each package ensures that the generated heat will not damage the PVC when considered in isolation, the vaults are thermally insulating and each vault location can store up to 14 packages. Simulant packages producing various heat outputs have been placed in a vault environment and the temperature recorded at various points within the packages. The results have allowed combinations of heat outputs to be derived which ensure that the PVC remains below 100oC in all the packages in the vault location. Storing one or two high power output packages together with a larger number of lower power output packages results in the optimum use of the storage capacity while ensuring the safety and integrity of individual packages.