Review of four decades dedicated to spent fuel analyses in france an incomparable database built for codes validation.

Abstract : This paper describes the experimental programs conducted in France by the Atomic and Alternative Energy Commission (CEA) in order to validate spent fuel inventory calculations and reactivity effects for core studies as well as fuel cycle studies. This large experimental program took almost 40 years to be completed and was defined within the framework of collaboration with our French partners, AREVA and Electricite de France (EDF). The experimental database comprises chemical analysis measurements (UOX, URE, UO2-Gd2O3 and MOX fuels) from fuel pin samples irradiated in reactors built in France. Additional information comes from full assembly dissolutions at the AREVA/La Hague reprocessing plants for UOx fuels. Furthermore, for some of analyzed fuel rods, specific samples of about 10 cm long have been extracted in the neighborhood of the analyzed sample in order to be oscillated in dedicated lattices in the MINERVE facility of the CEA at Cadarache, allowing the determination of the total reactivity effect versus the burnup of spent fuel compared to fresh reference fuel.This database is regularly updated and nowadays several hundreds of isotopic ratios are available.