THE 9975 SHIPPING PACKAGE LTE PREDICTION EFFORTS UPDATE

摘要

The 9975 shipping package, a robust drum-style Type B Fissile Package, is used for transport and storage of Plutonium metals or oxides. At Savannah River Site (SRS), up to 19 Watts of plutonium materials are stored in a triple-nested 3013 container assembly housed inside the 9975 double-containment vessel (CV). The shipping package structural components include the outer drum shell, fiberboard overpack, primary and secondary CV, lead shielding, bearing plates, and impact Iimiters made of aluminum-honey combs. The 9975 shipping package key functions include fire resistance, containment, and criticality prevention. The existing 15-year storage life for the oldest 9975 shipping packages will be reached in mid-July of 2017 and thus Life Time Extension (LTE) justification efforts have been on-going to extend the service life of the packages to 20-years. The storage life of the packages is mostly limited by the non-metallic components such as the fiberboard and dual CV O-rings. The initial submittal [1] focused on the comprehensive LTE prediction approach which combines existing material property data in conjunction with computer modeling (thermal, structural, and criticality). The package material data used in the computer models are based on as-designed configuration, field surveillance findings, and experimental studies. This submittal provides an update of the LTE prediction efforts with main emphasis on the bounding thermal analysis and results. Note that the 9975 shipping packages thermal, structural, and criticality analyses were recently completed. The three analyses concluded that the 9975 shipping packages in KAC meet intended functions to provide thermal resistance, containment, and criticality prevention during initial storage time as well as after 20-year storage service.