Citrate gel-combustion synthesis and sintering of nanocrystalline ThO2 powders

Highlights: • Nanocrystalline ThO₂ powders were prepared by using citrate gel-combustion method by varying the citric acid to nitrate mole ratio from 0 to 0.50. • TEM investigation revealed unimodal grain size distribution (6-16 nm). • For the first time EELS was used to estimate the branching ratio (B) of nc-ThO₂. • Sintered density as high as 98.8 ± 0.3 % T.D (243 MPa) was obtained by using "two-step sintering". • For the first time shrinkage anisotropy factor (α) was estimated and these values indicated that the ThO₂ monoliths had undergone near isotropic shrinkage.