[3M01-04] Fuel Behavior in SA and Long-term Storage

[3M04] Evaluation of annealing effect on MA-bearing MOX pellet with lattice defect

*Shun Hirooka¹, Masato Kato¹, Akira Komeno¹, Takeo Sunaoshi² (1. Japan Atomic Energy Agency, 2. Inspection Development Company)

Keywords:MOX, alpha decay, long-term storage, anneal

Minor actinide (MA)-bearing MOX fuel has been considered as a candidate for fast reactor with the purpose of reduction in volume and toxicity of high-level radioactive waste. Among MAs, Am-241 is a short-half-life radionuclide and the lattice defect by its alpha decay results in decrease of density and thermal conductivity. In this study, MA-bearing MOX pellets with lattice defect accumulated by alpha decay were annealed. The decreased density due to the lattice defect was recovered. However, the density started to decrease again above 1300C. Ceramography of the annealed pellets showed that the density decrease was attributed by helium pores formed along grain.