FUBILA: Core physics experimental program aimed at validation of core analysis method for high burn-up BWR full MOX cores

JNES has been performing a MOX core physics experimental program, FUBILA, that is aimed at obtaining the core physics characteristics of the full MOX BWR cores consisting of the high burn-up MOX assemblies with the average Pu enrichment from 9 to 11 wt% that corresponds to the assembly average burn-up from 55 to 65 GWd/t. For this program, BWR type test MOX rods were newly fabricated. The MOX pellets has the Pu enrichment of 3.0, 5.0, 8.5 and 11.5 wt% in a depleted uranium (0.25 wt% 235U) matrix. The critical experiments include several different core configurations for a 9x9 lattice, void simulations. B4C control rod insertion, burnable poisons, soluble boron in the moderator and a 10x10 lattice. The experiments are scheduled from January 2005 through June 2006 in the EOLE critical facility of the CEA Cadarache Center. The first critical state of the 9x9 full MOX assembly core was achieved on January 6, 2005 and the experiments are on going. The preliminary analysis of the first core has been performed with a continuous energy Monte Carlo code, MVP, and JENDL-3.2. The calculated results are consistent with the experimental data. (author)