High Moderation Boiling Water Reactors fully loaded with MOX fuel : The BASALA Experimental Program

摘要

This paper is devoted to the BASALA experimental program launched in the EOLE facility inrnCEA-Cadarache within the framework of a cooperation between the CEA, COGEMA and thernJapanese organization NUPEC. This programme, performed between 2000 and 2002, was aimed atrninvestigating the physical phenomena occurring in High Moderation Boiling Water Reactors fullyrnloaded with MOX fuel. The first configurations (BASALA-H) were dedicated to simulate hotrnoperating conditions by adjusting the moderation ratio and the second configurations (BASALA-C)rnto simulate further high moderation conditions than BASALA-H and corresponding to cold. Onernyear was devoted for the experimental study for each phase in which reference and perturbed (2×8rnand 2×16 Gd rods, voided and higher moderated cores, absorbing control blades) configurationsrnwere investigated. In addition integral soluble boron efficiency up to 600 ppm and the isothermalrntemperature coefficient up to 80℃ were measured in the BASALA-C reference core. The firstrnsection presents the experimental programme and the main results. One shows that the experimentalrndata were obtained with a very good accuracy, compatible with the required uncertainty to validaterncalculation tools for High Moderation BWR design. The second part describes the mainrncalculation/experiment results obtained by CEA and NUPEC : the calculation reproduce rather wellrnthe experiment (I.e. the fission rate is given within ±1.5% discrepancy in average).