IAEA reviews seismic safety at Korean plants

The International Atomic Energy Agency (IAEA) has concluded a five-day Site and External Events Design (SEED) mission to South Korea. The SEED team reviewed methods and criteria for evaluating seismic safety at the Wolsong and Shin Wolsong nuclear power plants, which are operated by Korea Hydro and Nuclear Power (KHNP).

Both facilities are located at the same site on the south-eastern coast, where an earthquake measuring 5.8 on the Richter scale struck in September 2016. The Vienna-based agency said the SEED team had examined the results of inspections carried out after the earthquake as well as the technical basis of hazard assessments and risk analyses. It also reviewed KHNP's mid-term action plans established in response to the 2016 earthquake.

"The IAEA team received information on the process and results that KHNP has conducted and obtained over the last four decades for assessing seismic hazards and safety at Wolsong and Shin Wolsong," said Shin Morita, head of the IAEA's External Events Safety Section. "The team was impressed by the positive attitude and concrete actions, taken by KHNP and partly coordinated with the government, to continuously improve safety against natural external events."

The team identified good practices, including the fact the government has a nationwide plan for assessing seismic hazards, enabling KHNP to update parameters of site-specific external natural hazards.

KNHP has established a new organization, the Seismic Engineering Office, "aimed at continuously improving safety against seismic hazards at all nuclear sites in the country, leveraging lessons and knowledge gained at the Wolsong and Shin Wolsong plants", the IAEA said.

The team also recommended on-going, comprehensive seismic hazard assessment measures that enhance alignment with IAEA safety standards.

When assessing the impact of actual earthquakes on safe nuclear power plant operation, the Cumulative Absolute Velocity should be used in the decision criteria, the IAEA said, so that operators are "able to determine the absence of potential damages with high confidence".

The SEED team comprised three experts from Argentina, Switzerland and the USA, as well as two IAEA staff. The team held talks with managers and experts at both KHNP's headquarters in the city of Gyeongju and at the site.

KHNP Executive Vice President Cheong-ro Yoon said the company would expand upon the experiences and knowledge it has gained to all nuclear power plants, including the Kori, Hanbit and Hanul facilities.

The mission, which concluded on 18 August, was requested by the Korean government. In accordance with IAEA practice, the final mission report will be delivered to the government within three months.

Researched and written
by World Nuclear News