Innovation in lifetime prediction of rigid polyurethane foam through random vibration and comparison with conventional methods

As the filling material for the new nuclear fuel transport cask, the rigid polyurethane foam plays an important role in the safe transportation of the nuclear fuel assemblies, and therefore its reliability deserves special attention. Thermal analysis and long-term ageing test are commonly used to predict the service lifetime of rigid polyurethane foams, but they cannot fully consider the influences of mechanical loads like vibration, collision, and impact etc., which is not satisfactory for the transportation application. Herein, in addition to the conventional thermal analysis and long-term ageing methods, the random vibration testing was particularly conducted on the rigid polyurethane foam that has been used in the new nuclear fuel transport cask for the nuclear power plants in China, and its service lifetime was innovatively predicted by the intrinsic property of material, the resonance frequency. The result which can be easily obtained from the acceleration data through fast Fourier transform without additional test and treatment was in the same order of magnitude with that from the conventional methods, and is more rational and convenient, deserving recommended for the rigid polyurethane foams that are used in other applications involving mechanical loads.