Implementation Of Burnup Credit Methodology On Orano Tn’S New Generation Transport Casks

Implementation of burnup credit methodology on OranoTN’s new generation transport casksM. TARDY1, S. KITSOS1, L. MILET1G. GRASSI21Orano TN, 1 rue des Hérons, 78 St Quentin en Yvelines, France2 Orano cycle, 1 place Jean Millier, 92084 Paris La Défense, FranceABSTRACTOrano TN has a wide experience in implementing BUrnup Credit (BUC) approaches for thetransportation of used nuclear fuel. Since the first implementation of a simplified burnupcredit approach in 1987, Orano TN has developed and licensed an advanced BUC approachbased not only on the consideration of major actinides but also some fission products whichare important for cask reactivity decrease. This advanced BUC approach is implementedsince 2013 in different Orano TN’ casks (TN® 24 E, TN® 17/2).Recently, Orano TN has licensed a new generation transport cask, namely the TN® 17 MAXcask, for the transportation of used nuclear fuel from European NPPs to the Orano La HagueReprocessing Plant (France) making use of the advanced BUC approach in the criticalitysafety assessment. In addition, the TN® 17 MAX cask is designed according to the latestIAEA regulation and will replace, in the short term, the TN® 17/2 cask currently used byOrano TN.This advanced BUC approach used for the TN® 17 MAX cask allowed to optimize safetymargins but required a more extensive validation process regarding the implementation ofthis methodology from a criticality safety point of view.This paper presents the different steps of the advanced BUC methodology implemented inTN® 17 MAX new generation transport cask including the main points required by the Frenchcompetent safety authority from an operational point of view.