[en] Thermal testing has been performed as part of development activities in support of the design of the TRUPACT (TRansUranic PACkage Transporter). The TRUPACT contains polyurethane foam in the walls and door to provide both impact and thermal protection. The environmental tests series to assess thermal protection have included radiant heating tests, small unit fire tests, and full-scale fire tests on foam bearing subsystems. To gather information on foam performance in both severe and near-regulatory environments, the polyurethane foams were tested in various configurations under fire simulation conditions. In parallel test programs, the foam underwent exposure to a radiant environment, (simulating the heat input to the foam from a fire) and exposure to an enclosed engulfing fire. The fire in this facility allowed for nearly uniform heat input in addition to approximating the chemical environment for the exposure of the unit. The test series described have led to the qualification of various foams for use in the TRUPACT on the basis of thermal performance, the benchmarking of the thermal code used to evaluate changes to the TRUPACT design, and confirmation of the basic design philosophy. From these tests it was determined that the candidate foams perform best in an anaerobic environment. For this reason, a design criterion for the puncture system was set that it shall protect the foam closest to the containment cavity from air ingress. The concern of foam exposure to air due to a puncture on the TRUPACT ends has been addressed through additional testing and analysis not discussed here