Establishment of a rapid method for the classification of CERN inter-site radioactive transport by measurement of equivalent dose rate

The European Organization for Nuclear Research (CERN) has premises on both sides of the French/Swiss border. As a consequence of the exploitation of the machines the activation of material is unavoidable. Inter-sites transports on public roads between the different sites represent around 1800 packages per year. Therefore, compliance with the ADR (European Agreement on the International Carriage of Dangerous Goods by Road) regulations is required. In order to classify this large number of transports efficiently, a pragmatic methodology to classify CERN’s activated radioactive goods via dose equivalent rate measurements has been developed. The ADR classification for material is based on the activity of the radionuclides contained therein. The purpose of the proposed method is to determine this via a simple dose equivalent rate measurement. In a first step, a study of the relationship between the dose equivalent rate and the specific activity of radionuclides has been carried out for 896 irradiation scenarios modeled with ActiWiz 2[i]. This method relates the dose equivalent rate of different materials with their nuclide inventories, taking into account the irradiation scenario and characteristics of the materials considered (chemical nature, mass, dimensions ...). A measurement of the dose equivalent rate of an object for which the irradiation history and its characteristics are known, then allows deducing the activity of the radionuclides it contains. In succession, the use of RAW-II[ii] allowed for determining dose equivalent rate limits that reflect specific transport classes for objects parametrized by their material type, dimension and irradiation scenario. This allowed for constructing envelope scenarios, removing the dependency on the often unknown irradiation history. Due to the high volume of transports, a set of various software tools has been developed which automatize the documentation of the complete transport process workflow.[i] C. Theis, H. Vincke, The use of ActiWiz in operational radiation protection, Proceedings of the SATIF-12 conference at Fermilab 2014, Nuclear Science Report NEA/NSC/R 3, (2015) [ii] R. Geyer, C. Theis, H. Vincke, D. Forkel-Wirth, The Radiological Workstation - an Efficient Tool for In-Situ Characterization of Potentially Radioactive Material, Workshop on Accelerator Radiation Induced Activation, ARIA 2015, Knoxville, Tennessee, (2015).