Characterization of spent fuel assemblies for storage facilities using non destructive assay.

Many NDA techniques have developed by the French Atomic Energy Commission (CEA) for spent fuels characterization and management. Passive and active neutronic methods as well as gamma spectrometric methods have bee carried out and applied to industrial devices like PYTHON and NAJA. Many existing NDA methods can be successfully applied to storage, but the most promising are the neutronic methods combined with on line evolution codes. For dry storage applications, active neutronic measurements require further R&D to achieve accurate results. Characterization data given by NDA instruments can now be linked to automatic fuel recognition. Both information can feed the storage management software in order to meet the storage operation requirements like: fissile mass inventory, operators declaration or automatic selection of proper storage conditions.