MOX core design in the full MOX-ABWR

Electric Power Development Co., Ltd. has started construction of an ABWR plant in OHMA-machi, Aomori Prefecture. The plant called the 'Full MOX-ABWR' has been designed to be capable to load mixed-oxide (MOX) fuels in whole core. The core of the full MOX-ABWR could be composed of MOX and UO2 fuel bundles, that maximum exposure is 40GWd/t and 55GWd/t respectively. The number of MOX fuels in initial core would be less than one-third of entire core, then be gradually increased to full MOX. Expanding the utilization capacity of MOX fuels, the plant would contribute greatly to the nuclear fuel recycling policy of Japan. Thus far, the core design case, that starts with an initial core with 264 MOX and reaches to full MOX in 3rd cycle, had been investigated as a licensed upper boundary case, in order to prove the feasibility of the full MOX core design in ABWR. Alternate core design cases would be examined in this paper to show the flexibility of the MOX core planning and design in ABWR. And also, additional design feature of the full MOX-ABWR, such as the consideration to the variation of Plutonium isotopic composition, MOX loading fraction dependent operational limit MCPR, increased maximum core flow rate, would be discussed in this paper. (author)