PROPOSAL TO SIMPLIFY LSA-III MATERIAL REQUIREMENTS OF IAEA TRANSPORT REGULATIONS

The LSA-II and LSA-III material requirements were introduced into the IAEA Transport regulations in the early 70s and revised in the 80s of last century. Meanwhile much progress has been achieved internationally regarding knowledge of material characteristics of LSA-II and LSA-III and their release behaviour under accident conditions of transport. In particular in Germany comprehensive experimental and theoretical research work was performed in recent years to investigate the release behaviour of various LSA-II and LSA-III materials under different mechanical impact conditions and to use the results to assess the potential radiation exposure resulting from such materials under severe handling and transport accident conditions. Based on this research work a review of LSA-II and LSA-III requirements was performed which was mainly focusing on the need and the justification of the LSA-III leaching test which have often be questioned in the past. For packages with LSA-III material it can be concluded that the achieved high level of transport safety is not connected with the currently required limited solubility of the material demonstrated by the leaching test but is resulting from the other required material properties. Therefore the performance of the leaching test for LSA-III material does not contribute to the requested safety level and can be omitted without decreasing the level of transport safety. This would help to simplify the Transport Regulations and to overcome difficulties regarding different interpretations and implementations of the leaching test in practice especially for radioactive waste. The paper summarizes the research results, describes the justification and the proposed changes to the regulatory text to delete the leaching test and gives an outline on how this proposal will be introduced into the next review and revision cycle of the IAEA Regulations for the Safe Transport of Radioactive Material No. SSR-6 [1].