Fabrication of (Pu_0.55U_{0 .45})C Fuel Pellets for the Second Core of the Fast Breeder Test Reactor in India

Around 200 kg of (Pu_0.55 U_0.45)C fuel pellets of relatively low density (86 ± 2% theoretical density) would be used as a driver fuel in the second core of the Fast Breeder Test Reactor in India. The current paper summarizes the production experience of the initial 15 kg of these fuel pellets following the “vacuum carbothermic synthesis” of tableted oxide-graphite powder mixture followed by “cold-pelletization” of carbide powder and “sintering.” The alterations made in the process equipment, radiation shielding arrangements, and fabrication parameters have been highlighted. The carbothermic synthesis and sintering were carried out in batches of 600 g and 1 kg, respectively. The percentage recovery of sintered pellets in all the batches was >90%. The resintering tests of pellets showed only marginal change in sintered density, ensuring minimum in-pile densification.