Abstract:
This document outlines the revised conceptual designs for a transport package for mixed-oxide (MOX) fresh fuel, developed to support the disposition of surplus weapons-grade plutonium. Two primary designs are presented: the end-loading concept and the double-strongback concept, both intended to safely and securely transport multiple fuel assemblies. A key component of the design and certification process involves rigorous analysis to ensure the package can withstand various normal and hypothetical accident conditions (HAC) without releasing its contents or becoming a criticality risk. To evaluate the structural integrity and performance under these conditions, the paper details the use of finite element analysis (FEA), specifically mentioning non-linear dynamic FEA programs like LS-Dyna. These tools are used for a range of analyses, including steady-state heat transfer, static pressure and compression tests, and large deformation non-linear analyses for free drop and penetration tests. For instance, preliminary puncture drop tests were performed using ABAQUS and Cosmos/M, which showed that the outer shell of the end-loading design could withstand the impact without a complete breach. The report also highlights that FEA programs' extensive libraries of material models, such as elastic-plastic and honeycomb, allow for the realistic simulation of complex structural behavior, including material failure and element deletion. This use of FEA is critical for providing a sound engineering basis for the designs before physical prototyping and testing, and will be essential for developing the safety analysis report required for official certification.
