Effects of Different Parameters on the Densities of Uranium Dioxide and Uranium Dioxide-Gadolinium Oxide Fuels Produced by the Sol-Gel Technique

Uranium dioxide-gadolinium oxide fuel was produced by the sol-gel technique. The effects of different parameters such as calcination and reduction temperature, compaction pressure, particle size of powder, type of binder, sintering temperature, sintering atmosphere, and duration of sintering on pore size distribution were investigated. The experiments were carried out on three different fuels, (a) pure urania, (b) uraniagadolinia (10%), and (c) urania-gadolinia (10%)-titania (0.1%) doped fuel. It was observed that compaction pressure as low as 200 MPa is sufficient to obtain highdensity pellets, while the use of binder or grinding the powder below 400 mesh does not affect densities. Reduction of powder at 1000 K always gives lower density fuels than the powder reduced at 873 K. Sintering at high temperature and the use of a wet atmosphere each independently increases the fuel density.