Development of the simplified MOX fuel fabrication process (short process). Fundamental examination of the pellet fabrication process

In the Plutonium Fuel Center, a study on the simplified MOX fuel fabrication process called the 'Short Process,' was conducted to decrease the fabrication cost of MOX fuel. In this 'Short Process,' the plutonium content is adjusted in the mixing step of plutonium nitric acid and uranium nitric acid, Pu/U mixed nitric acid is converted using the microwave heating denitration method and denitrated MOX is calcined and reduced. Obtained MOX powder is pelletized into green pellets without additives, and green pellets are sintered. Two types of granulation method were evaluated in the small-scale study: One is the calcination method and reduction method at high temperature and the other is the tumbling granulation method. By tumbling granulation, the powder was improved in a fluid index and the sintering density increased. Therefore, the 'Short Process' is feasible for the fabrication of highly qualified fuel pellets. (author)