Intensity‐Based Assessment of Off‐Site Building Damage and Human Casualties for Emergency Response Planning Near the Hanul NPP

Earthquakes affect not only nuclear power plants (NPPs) but also the surrounding infrastructure and essential response agencies. According to the emergency‐response procedures stipulated by the Nuclear Safety and Security Commission, organizations such as fire departments, police stations, local governments, and Korea Hydro and Nuclear Power (KHNP) support personnel are required to implement resident protection measures and facilitate nuclear‐accident recovery. This study derived quantitative indicators of earthquake‐induced damage conditions in the vicinity of NPPs. Focusing on the Hanul NPP site, scenarios were applied assuming safe shutdown earthquake levels of 0.2 g and 0.3 g, as well as the maximum possible earthquake magnitude in the Korean Peninsula (Mw 7.0). Using domestic attenuation relationships and building fragility curves based on spectral acceleration, the probabilities of building‐level damage and time‐dependent human casualties were estimated. The analysis indicated that as earthquake magnitude increases, damage to major public facilities—such as local government offices, fire stations, health centers, and hospitals—increases rapidly, reaching levels close to Extensive–Complete under the Mw 7.0 scenario. Widespread damage is also expected in KHNP residential complexes that accommodate nuclear plant personnel. Time‐of‐day analysis confirmed that residential facilities experience concentrated casualties at night (22:00–06:00), whereas office facilities show casualty concentration during daytime working hours. Building‐level assessments were performed to reflect Korea’s seismic characteristics and building fragility. Time‐dependent casualties and peak casualty occurrence periods were identified, and the vulnerability of support facilities directly involved in nuclear‐accident response was quantified. These results provide quantitative evidence to inform accident‐management and emergency‐response planning, serving as baseline data for enhancing the safety of communities surrounding NPPs.