Migration of neptunium-237 in glasses and ceramics

The integrated-residual-radioactivity method was used to obtain comparative data on the diffusion of neptunium-237 in model aluminoborosilicate and aluminophosphate glasses and also in clay-containing ceramics of two compositions. It was determined that the crystallization of the glasses affected the diffusion and that the water adsorbed by the ceramics affected the low-temperature migration of the radionuclide. It was determined that at elevated temperatures, both in the glasses and in the ceramics, neptunium-237 is one of the last mobile radionuclides. At a comparable temperature (500 degree C), the diffusion coefficient of neptunium-237 in the uncrystallized aluminoborosilicate glass was approximately three orders lower than in the ceramics