Evaluating the impact of climate change on the risk assessment of Nuclear Power Plants

Technical Systems, Structures and Infrastructures (SSI) ought to be designed to be safe under current but also future environmental (climate) conditions. Therefore, there is a need to rigorously identify procedures to systematically consider different climate conditions into the risk assessments. In this paper, we consider climate change in the risk assessment of a Passive Containment Cooling System (PCCS) of an AP1000 Nuclear Power Plant (NPP). Climate projections are obtained from the open-source database of the Climate Change Health Impact Profiles project (ClimateCHIP, www.climatechip.org) for the worldwide locations of the 15 existing (or planned) PCCSs. These climate projections are derived on one climate pathway of global future development (RCP 6.0) and five alternative climate models. We explore two ways of combining and communicating climate projections with the reliability assessment of a PCCS: an integrated probabilistic safety assessment conditional on climate projections and a risk classification based on an assessment of critical temperatures. We identify several challenges related to the way climate data are to be embedded into the system model, and the way the uncertainty of the results to be communicated to avoid over- and under-confidence in the risk quantification.