In order to assess the long-term safety of a repository for high-level radioactive waste, possible developments, including climatic changes, relevant to the design of the repository and the assessment of long-term safety must be determined and described for an assessment period of one million years. Reliable and scientifically sound prognosis of future climate evolution, especially under anthropogenic influence, is needed, but so far, a limited number of studies of long-term climate evolution have been performed. With the modeling of the future climate using physics-based climate and impact models, however, a quantitative assessment of the uncertainties with regard to possible future climate scenarios, including the timing and the extent of future glaciations in Germany, can be carried out.
The research project will address the following topics:
Using the new Earth system model of intermediate complexity (EMIC) CLIMBER-X, the Potsdam Institute for Climate Impact Research (PIK) will provide a set of future scenarios of climate evolution, including sea level changes, for the next 100,000 years (more detailed scenarios) and for the next one million years. The following figure depicts exemplarily the evolution of maximum summer solar irradiance at 65°N (top), the simulated CO2 concentration over the next 100,000 years for four colored cumulative CO2 emission scenarios (middle) and simulated ice volume (bottom) (Ganopolski et al., 2016). Based on the results from climate modelling, a detailed analysis of the model simulations will be performed to assess possible uncertainties in future scenarios related to the uncertainties in the cumulative anthropogenic CO2 emission and the uncertainties in the model parameters.
The Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) gGmbH will examine the effects of climate modeling and the uncertainties on the design of a repository system and develop strategies for dealing with uncertainties with regard to the long-term safety of a repository for high-level radioactive waste. In a first step, the important impacts of possible future climate scenarios on long-term safety will be compiled based on a literature review. Additionally, dose calculations will be carried out using biosphere models, that take into account both the current conditions in Germany and the assessments from the climatic models in order to map potential climate developments in Germany over the assessment period. In a second step, codes suitable for addressing selected topics of scenario uncertainties are selected, model calculations will be carried out and the results will be evaluated. A probabilistic sensitivity analysis will be used to systematically record and evaluate the influence of parameter uncertainties on the uncertainty of the results of the models. Finally, strategies for dealing with uncertainties regarding the long-term safety of a repository for high-level radioactive waste are developed.