Fabrication of Lanthanide Nitride Pellets and Simulated Burnup Fuels

摘要

Recent progress in the fabrication technique for the nitride fuel pellets, which is a part of the development of nuclear fuel cycle based on the nitride fuel and pyrochemical process, is described. Firstly, we reported here the parametric study for fabrication of the sintered pellets of DyN and (Dy,Zr)N. Dy was used as Am simulant and Zr was chosen as a dilutant for minor actinide (MA) transmutation. The results showed that the increase in milling time for DyN pellet fabrication, and sintering temperature for (Dy_(0.4)Zr_(0.6))N was the most effective to obtain high densities of sintered pellets. And then, we performed the fabrication experiment of simulated burnup fuels, which contained Nd as simulated rare earth fission product (FP) and Pd as simulated noble metal FP in UN matrix. For such fuels, Nd was found to be solely in solid solution, however precipitation along the grain boundaries was observed in case of Pd.