Safety Focus
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  • Wolsong Unit 1 & Kori Unit 1 Stress Test
  • Overview
  • Purpose
    • Aging nuclear reactors should be reviewed to evaluate their ability to withstand/respond to large-scale natural disasters exceeding design criteria in terms of license renewal
  • Targets
    • Wolsong Unit 1 (under review for license renewal) & Kori Unit 1 (continued operation in progress)
Wolsong Unit 1 (under review for license renewal) & Kori Unit 1 (continued operation in progress)
Wolsong Unit 1 Heavy Water Reactor, 679MWe, under review for license renewal, expiration of design life in November 2012
Kori Unit 1 Light Water Reactor, 587MWe, currently in operation, license renewed for up to 10 years in December 2007
  • Methodologies
    • In response to the nuclear power plant accident in Fukushima, Japan, a comprehensive special safety inspection is to be carried out based on EU stress test methodology, in accordance with safety measures adopted by the IAEA, Japan and the U.S., and also reflecting opinions of international environmental groups.

      In addition to EU’s stress test items, the special safety inspection includes evaluation of wide range fire, accident from human errors and decision-making process through Probabilistic Safety Assessment (PSA).
  • Scope
    • Durability of instruments, operational and human elements, and limit performance will be evaluated in the following five main inspection categories

      ① Earthquakes, ② Tsunamis and other natural disasters ③ Loss of safety functions (power systems, etc.),
      ④ Severe accident management, and ⑤ Emergency response.
  • Procedure
    • The operator(KHNP) is to conduct safety assessment based on guideline developed by the regulator(NSSC) and technical expert organization(KINS). And, a group of qualified experts is to review and verify the adequacy of the evaluation.
Assessment
guidelines established by
Regulator
=>
Safety assessment undertaken
by Licensee
=>
The adequacy of the assessment
results reviewed by
Experts
  • Principle
    • In terms of transparency principle, all the processes and results of the stress test are to be made public.
      * The public presentation is to be held for reflecting public opinion and building national consensus
      * The procedures and results keep public opening through the dedicated online website.
      * The civil verification team is to be organized in light of improving objectivity and reliability.
  • Current Status of the Wolsong Unit 1 Stress Test
Current Status of the Wolsong Unit 1 Stress Test
Date Description
April 30, 2013 Nuclear Safety and Security Commission (NSSC) confirmed stress test guidelines for Wolsong Unit 1 and Kori Unit 1 and notified them to Korea Hydro & Nuclear Power (KHNP).
July 12, 2013 The KHNP submitted the internal evaluation report of Wolsong Unit 1 stress test to the NSSC according to the ‘Stress test for aging nuclear power plants and notification of implementation guidelines’ (Nuclear Safety Division – 1958, Apr. 30, 2013).
August 9, 2013 Independent of a KINS verification team composed of about 90 experts, a private verification team consisted of 19 persons including 7 local resident , 9 related local experts and 3 civic group members.
August 30, 2013 The 1st meeting of the private verification team was held to discuss the team’s investigation plan
October 10, 2013 A comprehensive technology committee meeting was held to discuss and confirm the investigation schedule and items.
June 18, 2014 On 18th June, 2014, the expert verification teams delivered an interim reporting to local residents.
December 19, 2014 The expert verification on the stress testing of the Wolsong Unit 1 has been conducted by KINS verification team and the private verification team respectively for about 16 months since August 2013.

On 19th Dec., 2014, the final reporting session, which consisted of the verification results announcement and Q&A, was held for local residents to better understand the results.
January 6, 2015 The final report on verification of the stress testing of the Wolsong Unit 1 was disclosed to the public.
  • Current Status of the Kori Unit 1 Stress Test
Current Status of the Wolsong Unit 1 Stress Test
Date Description
April 30, 2013 The Korea Hydro & Nuclear Power Co., Ltd (KHNP) was notified of the guidelines for Wolsong Unit 1 and Kori Unit 1 Stress Test from the Nuclear Safety and Security Commission (NSSC).
May 6, 2013 The KHNP submitted its implementation plans for Wolsong Unit 1 and Kori Unit 1 Stress Test.
November 1, 2013 The KHNP postponed deadline for submission of its internal evaluation report on the Kori Unit 1 Stress Test considering the civil verification experts’ additional comments as well as the review results from overseas specialized agency.
December 20, 2013 The KHNP submitted its internal evaluation report on Kori Unit 1 to the NSSC in accordance with “Notification of NSSC DNS-1958: Implementation Plan and Execution Guide for Aging NPP Stress Test.
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