In order to clarify the potential risks of maritime transportation to the safe operation of coastal nuclear power plants, this study focused on risks of ship adrift and oil spills specific coastal nuclear power plant. Based on the influencing factors of water-related risks for nuclear power plants, a four-level hierarchical structure for water risk assessment was established. By conducting two-dimensional tidal flow model simulations in the vicinity of the nuclear power plant and carrying out typical ship drifting and oil spillage simulation experiments, a comprehensive evaluation of 11 risk indicators under 36 scenarios in normal weather and extreme typhoon weather was conducted using a combination of fuzzy evaluation method and Analytic Hierarchy Process (FAHP). In accordance with the criteria for maritime risk classification, the study identified graded control measures and safety management recommendations for the waters surrounding the nuclear power plant under normal weather conditions and during typhoons.