A CO2-based real options model for assessing the impact of external events on nuclear power plants

Nuclear power plants (NPPs) are essential for decarbonization. However, external events such as prolonged droughts or earthquakes have historically compromised NPPs' availability, undermining their decarbonization potential in national energy mixes. Life Cycle Assessment (LCA) is widely used to evaluate the CO₂e savings of NPPs, yet it typically assumes ideal operating conditions and fails to account for external events. Conversely, models that account for external events mainly adopt Real Options Analysis (ROA). Historically, ROA focuses solely on economic implications and considers monetary indicators (e.g., the price of electricity) while overlooking the impact on CO₂e savings. No ROA study has examined the impact of external events on NPPs from a CO₂e perspective. Yet, such external events are crucial, as empirically demonstrated by the reduced capacity factor of French reactors due to prolonged droughts. In response, we develop a novel model to assess the impact of external events on NPPs' electricity production from a CO₂e perspective. We developed and tested the model through a pseudo-real case study focused on drought events and their effects on NPPs' cooling systems. The model has three key novelties: 1) it consists of an enhanced LCA that incorporates the impact of external events on the NPP LCA; 2) it introduces a ROA approach based on CO₂e emissions as the evaluation metric instead of money; 3) it incorporates uncertainty by considering multiple CO₂e emissions scenarios simultaneously in the case of droughts impacting NPPs. • We developed a model to assess CO₂e impacts of external events on NPP availability. • We introduced a real options method using CO₂e emissions instead of monetary value. • We provided decision-makers with a tool to plan NPP resilience under external events. • We show that ROA is a valuable tool for planning NPPs more resilient to external events.