Thermal Analysis of a 9977 Shipping Package During a Fire-Drop-Smoldering Accident

Abstract

Abstract The US Department of Energy (DOE) uses the 9977 shipping package to store and transport plutonium bearing materials. The shipping package utilizes a single 6-inch diameter containment vessel with the radioactive material within SAVY-4000 containers, 3013 food-pack containers, or other sealed storage containers separated by spacers. The 6-inch containment vessel is surrounded by load distribution fixtures and a foam insulation overpack to protect against fire and impact events. A facility fire-drop-smoldering accident, which is longer and hotter than the comparable regulatory transportation evaluation, is analyzed to ensure radioactive material containment is maintained. A sensitivity analysis of shipping package configuration and foam insulation reduction is considered with foam eliminated either along the inside wall of the drum body (Inner Foam) or eliminated from the outer walls of the inner chamber where the 6-inch containment vessel is located (Outer Foam). These two different foam reduction configurations were considered to conservatively simulate the potential aging effects on facility safety qualification during storage. In addition, the thermal properties of the foam insulation were varied to explore their potential aging effects. A minimum foam thickness needed to maintain containment during the hypothetical facility fire-drop-smoldering analysis is determined for both the Inner and Outer Foam configurations as well as for both the SAVY-4000 and 3013 food-pack container configurations.