The French MOX fuel irradiations experiments. Present status and future improvement

For several decades, France has oriented its energy policy towards a closed nuclear fuel cycle program including the recycling of fissile material included in spent fuel. By September 1998, Fragema joint venture between Framatome and COGEMA delivered 1228 MOX assemblies to 17 EDF PWRs (900 MWe, 17 x 17), 2 German PWRs (900 - 1400 MWe, 16 x 16) and 2 Belgium PWRs (1000,1100 MWe, 17 x 17). Updating MOX product performance is going ahead according to a progressive and pragmatic approach including the experience feedback and the joint Rand D program involving the French partners Framatome, EDF and COGEMA with the CEA. The models used to justify the behavior of the current fuel products and to support the licensing of extended burn-up without prejudice to its maneuverability. The acquired experience feedback, together with the very satisfactory operating results has led to advances in MOX assembly zoning, and a modified fuel rod design. This product is sized for an assembly burn-up to 55 GWd/tHM depending on the operating conditions. The first AFA 2G (Advanced Fuel Assembly 2-Generation) MOX batches were delivered in 1995. Thus the accumulated irradiated experience together with the in-core behavior are presented. Moreover Rand D activities related to evolution, adaptation and continuous optimization of the recycling strategy are developed. (author)