Reaction layer growth and reaction heat of U–Mo/Al dispersion fuels using centrifugally atomized powders

Abstract The growth behavior of reaction layers and heat generation during the reaction between U–Mo powders and the Al matrix in U–Mo/Al dispersion fuels were investigated. Annealing of 10 vol.% U–10Mo/Al dispersion fuels at temperatures from 500 to 550 °C was carried out for 10 min to 36 h to measure the growth rate and the activation energy for the growth of reaction layers. The concentration profiles of reaction layers between the U–10Mo vs. Al diffusion couples were measured and the integrated interdiffusion coefficients were calculated for the U and Al in the reaction layers. Heat generation of U–Mo/Al dispersion fuels with 10–50 vol.% of U–Mo fuel during the thermal cycle from room temperature to 700 °C was measured employing the differential scanning calorimetry. Exothermic heat from the reaction between U–Mo and the Al matrix is the largest when the volume fraction of U–Mo fuel is about 30 vol.%. The unreacted fraction in the U–Mo powders increases as the volume fraction of U–Mo fuel increases from 30 to 50 vol.%.