Review of current Q system and the A₁/A₂ values of the IAEA Transport Regulations

The current Q system of the Transport Regulations published by the International Atomic Energy Agency (IAEA) was developed in the 1980s for calculation of A₁/A₂ values, i.e. the activity limits for type A packages. Over the years, the need came up for some additional A₁/A₂ values for nuclides not listed in the IAEA Transport Regulations SSR-6. Therefore, the German Federal Office for Radiation Protection (BfS) and the German Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (BMUB) granted a research project with the objective to analyse the methods used in the current Q system and to establish a program for the calculation of Q and A₁/A₂ values. The calculation tool BerQATrans enables not only to recalculate already known A values for nuclides listed in the IAEA Transport Regulations SSR-6, but also to determine the Q and A values for new radionuclides. The recalculation results of BerQATrans are in good agreement with the Transport Regulations SSR-6 for most of the A values. Furthermore, it is possible to recalculate Q and A values not even on the up to now used older data basis of ICRP publication 38 but also by using recent nuclide data presented in ICRP publication 107. Also newer dose rate coefficients published by International Commission on Radiological Protection (ICRP) can be used. During the development of the calculation program BerQATrans many lacks and inconsistencies in the documentation and problematic issues of the current Q system were identified and are briefly discussed in this paper. Other institutions made similar approaches to analyse and/or revise the Q system. In 2013, the work of these groups was also recognized by TRANSSC (Transport Safety Standards Committee) members. To gather their work an international working group was founded in Cologne. This Working Group on review of A₁ and A₂ Values for the IAEA Transport Regulations had several meetings with the aim of a comprehensive review and revision of the current Q system. First results and proposals were presented to TRANSSC in June and September 2015. (author)