Probabilistic Assessment of Exposure to Coastal Hazards at a Nuclear Power Station Development Site in the UK

A fundamental requirement for the development of nuclear power stations is an evaluation of the risk and exposure to external hazards that may challenge nuclear safety. These hazards are often driven by a wide range of meteorological, oceanographic, and geomorphological processes which act on varying spatial and temporal scales. For coastal flooding and erosion, assessing the hazard potential requires consideration of both the local wave and water level variations and the associated regional weather conditions. Fortunately, the development of downscaling techniques offers useful tools for transferring large-scale climate forcings to local impacts. This research aims to conduct probabilistic assessments of coastal hazard exposure at a nuclear power station in the UK by using a hybrid downscaling framework. First, a weather typing method is employed to statistically downscale from regional atmospheric conditions to coastal waves and storm surges at the Hartlepool nuclear power station, which will be further downscaled to coastal flooding and erosion using physics-based dynamical models. We performed a sensitivity analysis to determine what parameters are significant in weather typing to downscale waves and storm surges. The resulting weather types and their associated wave climate and surge conditions are useful in identifying weather patterns related to extreme wave and surge events, which helps to reduce the computational effort in dynamical downscaling by focusing on those coastal-risk weather types and investigating their impacts. The sensitivity analysis reveals that the inclusion of the gradient of sea level pressure as the predictor and the use of local predictands to guide the classification of weather types are important to improve the model performance.