Advanced fuel fabrication for fast reactors fabrication feed-back of three full-scale experimental assemblies for SUPERPHENIX

In July 1994, together with the administrative authorization of operation, a new mission had been assigned to SUPERPHENIX: to be a research reactor and to play a prominent role in the improvement of scientific and technological knowledge in the field of fast reactors. The so called 'Knowledge Acquisition Programme' (in French : P.A.C : 'Programme d'Acquisition de Connaissances') relied upon three basic axes: a) to prove the ability of a sodium cooled fast reactor to produce electricity on an industrial basis; b) to check the ability of a fast reactor to consume plutonium during normal operation, rather than to breed it; c) to evaluate the potential capacity of fast reactors to transmute and burn long lived radioactive material. Three experimental full scale fuel assemblies have been fabricated and delivered to SUPERPHENIX for irradiation: one with a high plutonium content, one with degraded plutonium, and one with 2% neptunium in the fuel. The fabrication equipment, as well as the fabrication process had to be adapted to the specific features of these assemblies. The fabrication feed-back and some recommendations for future experimental fabrication are extensively developed in the present paper. (author)