Development on multi-functional furnace for MOX fuel production

The Japan Nuclear Cycle Development Institute (JNC) produces the uranium/plutonium mixed oxide (MOX) fuels for the fast breeder reactor (Joyo and Monju) at the Plutonium Fuel Center, and now developed a multi-functional furnace for use at its production process. Sintering process at this MOX fuel production process contains three processing processes of de-fatting process (decomposition and removal of organic additives added at making pellets at 800 centigrade), sintering process (sintering of the pellets at 1750 centigrade) and de-gassing process (removal of volatile impurities remained in the sintered pellets at vacuum and 900 centigrade), which were carried out at every independent electric furnaces before now. Then, a so-called multi-functional furnace was developed at an aim of rationalization of processing apparatus integrated the processing functions of the sintering processes to one furnace under expectation on effects shown as follows: Reduction of space occupied by the apparatus to about one third of the conventional one to intend to reduce its introducing cost; Continuous execution of plural processing at one furnace to intend to reduce total processing time by upgrading of efficiency on temperature rising-up and falling-down time; and, Flexible response corresponding to processing in the processes by single or plural combined processing on the required one out of above-mentioned three functions. Here were described on developmental progress, experiments and evaluation on a trial production machine of the furnace, and so on. (G.K.)