SPENT FUEL TRANSPORTS IN FRANCE LESSONS LEARNED FROM 1998 CRISIS

In May 1998, all French domestic transports of spent fuel assemblies from EDF Nuclear Power Plants to the COGEMA Reprocessing Plant (about 200 transports per year) were temporarily suspended because a significant fraction of those transports showed levels of non-fixed surface contamination exceeding at the arrival the routine regulatory limit of 4 Bq/cm² for b and g emitters. Abroad, Germany and Switzerland also suspended this type of transports. Under the supervision of the French Nuclear Safety Authority (DSIN), in charge of monitoring radioactive and fissile material for civil use since June 1997, the introduction of improvements in terms of preparation of the flasks, contamination measurements and rules for exchange of information, enabled the resumption of transports in France in July 1998. Abroad, transports also resumed in Switzerland in August 1999, and in Germany in April 2001. The detailed analysis of this event pointed out that: - the recorded levels of surface contamination exceeding 4 Bq/cm² did not have any radiological consequence as far as health effect is concerned ; in fact this limit is a derived limit which has substantial safety margins in the modeling underlying its derivation, and the limit can rather be depicted as a cleanliness goal, - the design of the flasks was demonstrated not to be a cause, - conventional techniques for protection, handling, loading and unloading of the flasks can and do lead to acceptable results. This paper describes the lessons learned from this event, especially in terms of: - techniques to be shared by Nuclear Power Plant operators and Reprocessing Plant operators for protection, handling, loading and unloading of the flasks, - overall responsibility of safety and radiological protection which has to be fully taken by the operators (as consignors of such shipments) up to the arrival of the shipment at destination, - education and information of all parties involved in such transports (railways workers for instance). Their implementation leads to a dramatic reduction of the number of cases of exceeding the regulatory limits: from 35% before the stop of the transports down to 2% of the about 200 transports performed in 2000. In addition, it should be noted that for these few cases, the limits were only slightly exceeded.