ASSESSMENT OF SAFETY DEMONSTRATIONS RELATIVE TO PACKAGES CONTAINING UF6

The safety demonstrations realized by applicants in the case of approval request for the package designs containing enriched UF6 have to take into account some specific technical issues. Concerning the shipment of enriched UF6, the package designs consist in general of a filled 30B cylinder surrounded by an overpack.The description of the content, considering the UF6 origin, i.e. natural or reprocessed, shall be clearly justified especially when the UF6 isotopic composition exceeds the limits specified in ASTM standards.Concerning the containment of the UF6, the applicant shall demonstrate in all conditions of transport the leak-tightness of the valve and plug of the cylinders filled with enriched UF6. In this regard, when mechanical justifications are based on numerical calculations or experiments, the absence of contact between these components of the cylinder and the internal surfaces of the overpack after the regulatory drop tests shall be shown to respect the IAEA regulations.Furthermore, the representativeness of the ballast used to simulate the behaviour of the UF6 loaded within the cylinder shall be justified if drop tests are performed. The representativeness of the ballast should also be justified for numerical calculations.In addition, the applicant shall demonstrate that the melting temperature of the valve and the plug, including the tinned joint, will not be exceeded during the regulatory fire test.Finally, specific provisions relative to the use of plugs and the maintenance of cylinders should be included in the safety analysis report.