Method of fabricating nuclear fuel pellets

Purpose: To use uranium tetraoxide as a pore forming agent thereby to produce UO2 nuclear fuel pellets having stable pores almost not liable to shrink by heat or radiation during the operation of the reactor. Method: UO2 powder, alone or added with a Gd2O3 powder up to 6% of the former as a neutron absorber, is mixed with 5 to 15% based on mixed powder of UO4, nH2O powder of 10 to 325 meshes. Thus obtained mixed powder is pressed, formed, and sintered. In the sintering process, UO4.nH2O gradually loses its crystal water, and is converted into UO2, it shrinks and pores remain in the sintered body. (Kamimura, M.)