Sintering Studies of Ga-Doped CeO2 (Ga-Doped PuO2 Surrogate) for Mixed Oxide Nuclear Fuel

Sintering studies of CeO2 and CeO2 + 2 wt. % Ga2O3 were completed. Firing temperatures studied were 1250-1650 C with 2 to 4 hour firing soak times in air. Powders fabricated by three methods (as-received, attrition-mill and nitrite-derived) were studied. Attrition-milled CeO2 improved densities as compared with as-received CeO2. Attrition-milled CeO2 with 2 wt.% Ga2O3 showed decreased densities with increasing temperatures. As-received CeO2 with 2 wt.% Ga2O3 showed a opposite trend, increasing in density with increased firing temperature. Two pellet preparation methods were studied, a one-step-press method and a two-step-press method. The two-step-press method showed greater densities at lower firing temperatures and times as compared with the one-step-press method, however for CeO2 + 2 wt.% Ga2O3, the two methods gave equivalent results at 1650 C, 6 hr. firing conditions