Fire Durations of Concern for a Modern Legal-Weight Truck Cask

The response of a truck package to a radiation fire model is simulated for a range of fire durations using three-dimensional finite element analysis. A model is developed to determine the cumulative seal degradation from its temperature-versus-time history. This model is used to determine the minimum fire duration that causes the seal to lose containment integrity. The fire durations that cause the cladding to reach its long-term creep deformation and burst rupture temperatures are determined and found to be longer than the durations that cause the seal to lose containment integrity. These simulations are repeated for package models without the compliant regions of the impact limiters, and for a package with the impact limiter completely removed. Those simulations quantify the level of thermal protection the impact limiters provide to the seals and cladding during simulated fires.