Framatome experience in fuel assembly repair and reconstitution

Since 1985, FRAMATOME has build up extensive experience in the poolside replacement of fuel rods for repair or R and D purposes and the reconstitution of fuel assemblies (i.e. replacement of a damaged structure to enable reuse of the fuel rod bundle). This experience feedback enables FRAMATOME to improve in steps the technical process and the equipment used for the above operations in order to enhance their performance in terms of setup, flexibility, operating time and safety. In parallel, the fuel assembly and fuel rod designs have been modified to meet the same goals. The paper will describe: - the overall experience of FRAMATOME with UO2 fuel as well as MOX fuel; the usual technical process used for fuel replacement and the corresponding equipment set; - the usual technical process for fuel assembly reconstitution and the corresponding equipment set. This process is rather unique since it takes profit of the specific FRAMATOME fuel assembly design with removable top and bottom nozzles, so that fuel rods insertion by pulling through in the new structure is similar to what is done in the manufacturing plant; - the usual inspections done on the fuel rods and/or the fuel assembly; - the design of the new reconstitution equipment (STAR) compared with the previous one as well as their comparative performance. The final section will be a description of the alternative reconstitution process and equipment used by FRAMATOME in reactors in which the process cannot be used for several reasons such as compatibility or administrative authorization. This process involves the pushing of fuel rods into the new structure, requiring further precautions. (author)