The mass fractions of CaO in doped UO2-10 wt% Gd2O3 fuel
pellets were 0, 0.3%, 0.5% and 0.6%, respectively calcium hydroxide
was weighed according to the proportion of CaO and stirred with
5 ml water. 1e2 ml concentrated nitric acid was added and dissolved
to get stable Ca(NO3)2 solution. By rapid stirring, Ca(NO3)2
was slowly dropped into the mixed solution of UO2(NO3)2 and
Gd(NO3)3. In the end, uniform mixed solution of UO2(NO3)2,
Gd(NO3)3 and Ca(NO3)2 was prepared.