Beyond design basis issues in the Republic of Korea

Shortly after the Fukushima Daiichi accident, all nuclear facilities in the Republic of Korea were inspected to ensure the countermeasures against severe accidents were adequate and in full agreement with the safety inspection principles. In particular, a close examination of Kori Unit 1, the oldest reactor in operation in the country, was undertaken to confirm its safety during the period of continued operation beyond its design life. The inspection team consisted of 56 experts in the areas of earthquake/tsunami, electric power/fire/reactor cooling, severe accident, emergency planning and LTO. This review included: — Confirming unit safety during a design basis earthquake and tsunami; — Securing reactor cooling capability in case of station blackout due to severe flooding; — Securing containment integrity, assuming loss of reactor cooling capability; — Adequacy of the emergency response, assuming large release of radioactive materials; — Close examination of the ageing of the Kori Unit 1 AMP. Based on special inspections, investigations and research in the country, it could be confirmed that NPPs in the Republic of Korea will remain safe even during a massive earthquake and tsunami. Nevertheless, dozens of short and mid-term severe accident coping features have been recommended to better mitigate beyond design basis accidents