Climate Change in Central Europe and its Effects on External Hazards for Nuclear Facilities

For nuclear facilities, external hazards are major contributors to the overall risk. Due to global warming, the frequency and intensity of certain types of external hazards may change. This holds, in particular, for hydrological and meteorological hazards. Therefore, GRS assess the climatic changes to be expected in Central Europe over the coming decades and their effects on the safety of nuclear power plants (NPPS), interim storage facilities and repositories for nuclear waste (during their operation phase) in the framework of the research project “Einfluss des Klimawandels auf die Sicherheit kerntechnischer Anlagen” (KlimakA) funded by BASE.

At the beginning of the project, a literature review on climate projections for Central Europe has been performed. The focus of this review was on information regarding extreme events with low exceedance frequencies, because this type of events is most relevant from a safety point of view. Depending on the facilities under consideration different time horizons are of interest: While for European NPPs the focus is on the next 60 to 80 years, for interim storage facilities and repositories longer time scales, up to well into the 22^nd century, are of interest. The study led to the following insights: (i) Climate projections are subject to large uncertainties. (ii) Evaluations with respect to events with low exceedance probabilities are scarce. (iii) Projections for changes beyond the current century are almost non-existent. (iv) With the exception of temperature increase, changes of hydrological and meteorological effects due to climate change will be limited for most central European countries.

Based on an evaluation of the worldwide NPP operating experience, a review of the design of European NPPs with respect to external hazards and considering the WENRA requirement to protect NPPs against hazards with return periods of 10.000 years, there is currently no indication of a major increase of the overall risk due to climate change. Nevertheless, operational challenges may arise. Hazards predominantly contributing to safety related effects are lightning strikes, high winds, biological hazards, low temperatures, and flooding events.

As interim storage facilities are less dependent on active systems than NPPs, their safety will probably be even less affected by climate change. One caveat being that climate projections beyond 2100 are scares and depend on uncertain assumptions. But as the pertinent design requirements for interim storage facilities are similarly high as those for NPPs, a high level of robustness of interim storage facilities can be expected. Similar considerations hold for the surface installations of repositories which will be assessed in the next step of KlimakA.