French requirements for the design, manufacture and use of bolts and screws equipping packages for the transport and storage of radioactive material

International audienceIn order to guarantee the behaviour of components important for safety in all conditions of transport, a specific attention should be paid on the bolted flange and screwed assemblies.In this regard, The French nuclear safety authority for defense activities (ASND) and its technical support, the Institute for radiation protection and nuclear safety (IRSN), initiated a working group to identify good practices related to: - the design of screwed assemblies by specifying allowable criteria in all conditions of transport; - the representativeness of screwed components equipping mock-ups or specimens used during drop tests in terms of mechanical properties, dimensions and screws preload; - the hypothesis considered to model, by numerical calculations, the mechanical behavior of the screws; - the manufacturing process to prevent notably the risk of hydrogen embrittlement and the supplying controls to check the as-built properties of the screws; - the instructions for use by listing good practices (star or cross order, time to reach the thermal steady state of the components, markings …).The conclusions of this working group, taking into account transport events feedback and involving the main French applicants (CEA and ORANO TN), will be introduced in a dedicated guidance supported by ASND. The guidance aims at ensuring a high safety level of the radioactive material transportation

French requirements for the design, manufacture and use of bolts and screws equipping packages for the transport and storage of radioactive material

International audienceIn order to guarantee the behaviour of components important for safety in all conditions of transport, a specific attention should be paid on the bolted flange and screwed assemblies.In this regard, The French nuclear safety authority for defense activities (ASND) and its technical support, the Institute for radiation protection and nuclear safety (IRSN), initiated a working group to identify good practices related to: - the design of screwed assemblies by specifying allowable criteria in all conditions of transport; - the representativeness of screwed components equipping mock-ups or specimens used during drop tests in terms of mechanical properties, dimensions and screws preload; - the hypothesis considered to model, by numerical calculations, the mechanical behavior of the screws; - the manufacturing process to prevent notably the risk of hydrogen embrittlement and the supplying controls to check the as-built properties of the screws; - the instructions for use by listing good practices (star or cross order, time to reach the thermal steady state of the components, markings …).The conclusions of this working group, taking into account transport events feedback and involving the main French applicants (CEA and ORANO TN), will be introduced in a dedicated guidance supported by ASND. The guidance aims at ensuring a high safety level of the radioactive material transportation