Deep geologic disposal of radioactive waste
One of the major problems with nuclear power plants is what to do with the spent fuel rods. Their levels of radioactivity are so high that several thousand years must pass before they are safe for the environment. Until then they must be isolated. Deep geologic disposal has risen to the fore as the most pragmatic solution to the nuclear waste management issue, beating out deep sea burial and dumping in outer space. The critical weakness in geologic disposal is the threat of leakage of radionuclides outside the repository. Research supported by EURATOM Framework Programme focused on the geosphere, the buffer region between the repository and the biosphere. In the context of the project, entitled RETROCK, the Swedish Nuclear Power Inspectorate (SKI) gauged the suitability of today's computer models to correctly assess the risk for any particular site. The most important processes to be simulated include radioactive decay, transport and phenomena that describe how the radionuclides escape in the gas, liquid and solid phases. The results of SKI's work show that there are no glaring weaknesses in the current assumptions. They also outlined what organisations can do when insufficient data regarding the geologic characterisation of the site is available. Finally, a consensus is reached regarding the next steps for furthering model development. SKI's research has been compiled in a report, EUR 21230 EN, which is available on the RETROCK website. The report will be useful for organisations carrying out Performance Assessments (PAs) for potential deep geologic disposal sites.