Effect of oxygen‐to‐metal ratio on densification behavior in the sintering process of PuO₂ pellets

Abstract

The effect of oxygen‐to‐metal (O/M) ratio on the sintering behavior of plutonium oxide pellets was evaluated from shrinkage measurements in isochronal heating from 973 K to 1923 K and isothermal heating at 1573 K and 1923 K. Air and Ar/H2 gas for which its P/P ratio was controlled using added moisture (H2/H2O) were used as measurement atmospheres. During isochronal heating, shrinkage began at lower temperature with increasing P/P ratio in the Ar/H2 gas atmosphere. On the other hand, shrinkage began at the lowest temperature, 1100K, in the air atmosphere and sintering in air was dominated by two mechanisms. During isothermal heating, the sintering mechanism was evaluated from the shrinkage ratio. In each atmosphere, sintering was dominated by a slow sintering mechanism. Grain growth did not progress in air and it depended on P/P ratio in the Ar/H2 gas atmosphere with added moisture. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Thermal conductivity measurement of (Pu1−xAmx)O2 (x=0.028, 0.072)

“…From the aspect of sintering behavior, Am3 and Am7-3 specimens were well sintered compared to the Am7-1 specimen considering their high sintering densities and fewer numbers of cracks. Uchida et al [21] have been evaluated the sintering behavior of PuO 2Àx regarding selected conditions, e.g. oxygen partial pressure of atmosphere, pre-heat treatment, and sintering temperature.…”