Sound speeds in and mechanical properties of (U,Pu)O_2-x

The sound speeds of longitudinal and transverse waves in the uranium-plutonium mixed oxide pellets were measured as functions of porosity, oxygen-to-metal ratio, and plutonium content. The effect of each parameter was well fitted by a linear function and the equations were obtained to calculate the sound speeds. Mechanical properties were evaluated with the sound speeds and the result of Young's modulus showed that porosity was the most important factor to decrease Young's modulus. Temperature dependence on Young's modulus was also evaluated with previously reported thermal expansion. Decrease of Young's modulus with increasing temperature was in good agreement with available literature. (author)