A dynamic modelling framework to assess the impact of manual emergency responses on nuclear power plant resilience

• Framework insights guide strategic decisions for EPRTs and safety system placement. • PN models effectively evaluate emergency maintenance impact on NPP resilience. • The study enhances understanding of human efficiency’s role in NPP resilience. The escalating frequency of extreme natural disasters due to climate change poses unprecedented risks to nuclear power plants (NPPs), underscoring the need to quantify the efficacy of manual emergency responses in enhancing resilience. However, quantifying the effectiveness of these measures remains a significant challenge. This paper develops a Petri Net-based resilience assessment framework to model multi-phase accident progression in an NPP subjected to extreme events, including loss of coolant accidents and station blackout scenarios. The PN models integrate stochastic system degradation processes, automated safety responses, manual recovery processes, and offsite resource mobilisations. The simulation results show that the developed model can successfully assess the impact of the efficiency of human responses on NPP resilience. This work provides actionable insights for optimising NPP emergency procedures and resource allocation strategies. The findings underscore the importance of timely manual interventions during emergency scenarios, offering a quantitative basis for enhancing nuclear safety management policies.