Restructuring and redistribution of actinides in Am-MOX fuel during the first 24h of irradiation

Tanaka, Kosuke  ; Miwa, Shuhei  ; Sekine, Shinichi; Yoshimochi, Hiroshi; Obayashi, Hiroshi ; Koyama, Shinichi  

In order to confirm the effect of minor actinide addition on irradiation behavior of MOX fuel pellets, 3% and 5% americium-containing MOX (Am-MOX) fuels were irradiated for 10 minutes at 43 kW/m and for 24 hours at 45 kW/m in the experimental fast reactor Joyo. Two nominal values of the fuel pellet oxygen-to-metal ratio (O/M), 1.95 and 1.98, were used as a test parameter. Emphasis was placed on the behavior of restructuring and redistribution of actinides which directly affect the fuel performance and the fuel design for fast reactors. Microstructural evolutions in the fuels were observed by optical microscopy and redistribution behavior of constituent elements was determined by mapping and quantitative point analyses of EPMA.