Year
2010
File Attachment
Abstract
A transport risk assessment study has been conducted for transport of radioactive waste with negligible heat-generation (low- to medium-level) to the German final repository Konrad. This study is a revision of the former Konrad Transport Study performed by GRS in 1991 implementing updated waste data among other improved methods and assumptions for the purpose of a more realistic approach to risk assessment. According to the results of the revised survey each year approximately 2300 shipping units of low and medium active waste will be transported to the Konrad site starting with its expected begin of operation in 2014. The first part of the transport risk assessment study concerns the radiological consequences from routine (incident-free) transportation of radioactive material, i.e. the radiation exposure of transport personnel and the public (expected exposure). Based on the assessed detailed information on transport arrangements and on the average number and radiological characteristics of waste packages the maximum annual effective doses for the representative persons were estimated. The results show predicted doses far below the relevant German annual statutory dose limits. The risk associated with transport incidents and accidents has been quantified for the area within a radius of 25 km around the repository site. The probabilistic method adopted in this study considers parameters as the frequency and severity of railway or road accidents, characteristics of radioactive waste and transport packagings and the frequency of atmospheric dispersion conditions. From a large set of parameter combinations the spectrum of potential radiological consequences and of the associated probability of occurrence was assessed. Compared to the former risk analysis of 1991 a revised set of release fractions for mechanical and thermal impact conditions and a modern Lagrangian particle dispersion model have been applied. In combination with the updated waste database and revised transport scenarios these changes result in potential radiation exposures in the repository area which are about one order of magnitude lower than predicted in the former study