Release concepts of a new Radiation Protection Ordinance according to Euratom Basic Standards 2013 in application

Within the framework of the research project 4717E03510, a compilation of all radiolog-ical models, their scenarios, exposure pathways and parameters on which the clearance in the Radiation Protection Ordinance is based is being made. It was shown that the release values given in the Radiation Protection Ordinance StrlSchV (2017) in columns 5, 6, 7, 9a-d, 10 and 10a are mostly consistent with those in the researched literature. With regard to column 8 of the Radiation Protection Ordinance StrlSchV (2017), the initially observed deviations between the literature values and those in the StrlSchV (2017) could be largely clarified. In a next step, the boundary conditions of the models for the calculation of the clearance values in the StrlSchV (2017) were identified; their origin was researched and described. It turned out that the information regarding the model boundary conditions is plausible to a great extent and that the data is consistent. Based on the aforementioned findings, the essential model parameters of the radiological models for calculating the clearance values were identified, and their range of variation was discussed. The clearance values specified in the current Radiation Protection Ordinance StrlSchV (2018) are based on 'generalized' exposure scenarios that represent the wide range of exposure situations. For a selection of nuclides, a probabilistic approach based on parameter distributions was examined for several nuclides in addition to the usual deterministic calculation from the given (realistic and improbable) parameter values. For selected scenarios, further calculations of clearance values were performed using freely available calculation codes. The plausibility of the results was checked by comparative calculations of other organizations (benchmarking). In this context, it was shown that two programs used at GRS could determine the dose coefficients for the analysis of external radiation exposure. A selected program was used to model the water dispersion from a landfill. The comparison of the values calculated with those models used by established companies shows a good agreement for most nuclides. Furthermore, the program system Atmospheric Radionuclide Transport Model (ARTM) for the calculation of the dispersion and deposition of released airborne radioactive substances was used for the first time for the calculation of clearance values. In the 'ingestion' scenario, significantly lower release values were calculated with ARTM than in the literature. The Öko-Institut also comes to a similar conclusion in its calculations. In a current literature source, these major differences in the calculations were clarified.