지진발생시 원전 안전성 검토 및 조치에 관한 연구

Abstract

After the accident in Fukushima Daiichi nuclear power plants (NPPs) and the earthquakes in Gyeongju and Pohang, there has been an increase in public interest in the safety of NPPs under seismic conditions. Thus, it is important to review the influence of seismic event on the safety of NPPs. Therefore, the regulatory guidelines of seismic design, design procedure, and seismic monitoring system of NPPs were reviewed in this study.

In addition, the system, structure, and components (SSCs) of NPPs and operating parameters affected by the earthquake were identified, and the responses of the SSCs and parameters during the earthquake event were reviewed from the earthquake experiences of NPPs in Korea and Japan. Based on these, appropriate reviews and actions were proposed to ensure the safety of NPPs in the events of an earthquake.

The key procedure of seismic design is consisted of decision of design earthquake, dynamic seismic response analysis, seismic design of structures and equipment, and seismic verification of equipment. In the dynamic seismic response analysis, the ground-structure interaction analysis should be added if the ground condition is not sound compared to the reference value.

For the safe operation of NPPs during the seismic event, it is important to understand the responses of structures and equipment of NPPs under seismic condition and to take appropriate action to mitigate the abnormal responses. Thus, this section reviews the expected responses and analyses the effects of the responses on the safe operation of the NPPs.

Based on the reviews of guidelines of seismic design and responses of NPPs under seismic events, it was concluded that the current design of Korean NPPs has no critical problems in terms of safe operation and safe shutdown during the earthquake event. To further enhance the safety of NPPs under seismic events, however, it is necessary to manage the lifetime of affected equipment and seismic verification of spare parts. Also, repeated training and emergency training on the response of NPPs in the event of earthquake are required.