PARFREI

The German site selection process for a deep geological repository for high-level radioactive waste as stipulated in the site selection act (StandAG) is a science-based iterative process. The Federal Company for Radioactive Waste Disposal (BGE) is responsible for developing the site selection process (Standortauswahlverfahren), which is implemented in a stepwise approach. With the identification of potential siting regions, preliminary safety investigations (vorläufige Sicherheitsuntersuchungen, vSU) have to be carried out. In step 2 of phase 1 of the site selection process, representative preliminary safety investigations (repräsentative vorläufige Sicherheitsuntersuchungen, rvSU) are to be performed. A particular challenge is the adequate description and assessment of the potential radionuclide migration in the repository systems. Besides processes such as advection, diffusion, sorption and radioactive decay, the corrosion of the waste forms and subsequent dissolution and precipitation of radionuclides are of relevance and interest.

The research work performed in PARFREI provided quantitative data on the release, solubility and sorption of radionuclides as input for the rvSU. PARFREI was jointly carried out by the Institute for Nuclear Waste Disposal of the Karlsruhe Institute of Technology (KIT-INE), the Institute for Resource Ecology at the Helmholtz Center Dresden-Rossendorf (HZDR) and the Institute of Fusion Energy and Nuclear Waste Management (IFN-2) of Research Center Jülich (FZJ). Based on the evaluation of the hydrogeochemical conditions in the various siting regions, PARFREI provides comprehensive lists of parameters to quantify potential radionuclide mobility, and discusses the available underlying process understanding, also critically reflecting the international state of the art in science and technology.