A NEW OVERPACK FOR THE TRANSPORT OF UF6 IN 30B CYLINDERS

Facing the difficulties met in the United States to obtain a dw-able certificate of approval for the existing overpacks, COGEMA wished to free itself from the constraints imposed by these packagings for the transport of enriched UF 6. Transnuch\\aire therefore initiated, on behalf of COGEMA, the design of a new type B(U)F overpack for use with the 308 cylinders containing hexafluoride uranium enriched up to 5% in U235, obtained from natw-al or reprocessed uranium. The external aspect of the new overpack is quite standard (two cylindrical halves closed with ten toggles) and it keeps the same stowing system so that it can be used with the transportation means that already exist. The main features of Transnucleaire's overpack are a reinforced internal structure to protect the 308 cylinder's skirt against bending, and a better absorption of the drop energy in order to limit the acceleration under impact. The drop tests and a fire test have been performed successfully in February and March 1997 and the Safety Analysis Report has been submitted to the French Competent Authority, with a view to obtain the corresponding approval mid 1998.