Regulatory Approach to the Lifetime Management of the Nuclear Power Plants in Korea

1. International Conference on 50 Years of Nuclear Power – the Next 50 Years Obninsk/Moscow, Russian Federation Regulatory Approach to the Lifetime Management of the Nuclear Power Plants in Korea June 30, 2004 Choi, Kyung Woo Korea Institute of Nuclear Safety

2. Contents • Introduction • Current Regulation Related to Life Management • Periodic Safety Review System • Plant Life Management Evaluation Factors • Procedural Requirements for Plant Life Extension • Summary

3. Introduction • There are 18 NPPs in operation and 2 NPPs under construction in Korea, since the 1st NPP started its commercial operation in 1978. • 9 NPPs have been operating more than 10 years, and Kori unit 1 is approaching its design life of 2008. (Wolsung unit 1: 2013) • Public concern has been increased on the safety of operating NPPs. • Systematic and comprehensive operational safety assessment and plant life management are necessary to maintain a high level of safety • Taking account of improvements in safety standards and practices, the cumulative effects of plant ageing, operating experience, and the evolution of science and technology.

4. Status of Nuclear Power Plants in Korea

5. Introduction • Operating license is issued without a fixed term in Korea. • Design life is established in FSAR for the basis of design and safety assessment. • It is ambiguous whether the continued operation beyond the design life is accepted or not in the legal and technical aspects. • Institutional scheme for the plant life extension should be carefully considered in the very near future, considering the remaining life of Kori unit 1 and the time required for the safety assessment. • The technical and economic feasibility studies for the lifetime management of NPPs have been carried out for the last 10 years.

6. Introduction • Periodic safety review (PSR) system was introduced and established with sound legal basis in order to evaluate the comprehensive and systematic safety of operating plants. • The PSR scope is based on the safety factors suggested by the IAEA. • The results of PSR with focusing on ageing assessment can be utilized for the life extension. • Nuclear Safety Commission in Korea recommended using the results of PSR in the life extension of NPPs.

7. Current Regulations on Life Management • Legal Basis for Regulation • Atomic Energy Act • Enforcement Decree of Atomic Energy Act (Presidential Decree) • Enforcement Regulation of Atomic Energy Act (Ministerial Decree) • Regulation on Technical Standards of Nuclear Installation (Ministerial Decree) • Regulation on Technical Standards of Radiation Protection (Ministerial Decree) • Notice of the Minister of Science and Technology

8. Current Regulations on Life Management • Licensing Procedural Requirements • Construction Permit: • Early site approval for limited construction work on a proposed site before the construction permit is issued. • Operating License: • No prescriptive limit on the license term: design life specified in FSAR • Decommissioning: • Approval of a decommissioning plan

9. Current Regulations on Life Management • Design Requirements • Quality Standards • Environmental & Dynamic Effects Design Bases • Qualification Requirements of equipment • Abilities for Test, Monitor, Inspection & Maintenance • Inspection Requirements • Pre-operational Inspection • Periodic Inspection • Quality Assurance Inspection

10. Current Regulations on Life Management • Requirements on Safety Measures for Operation • Conformance to Technical Specification (TS) • Feedback of Operating Experience • Testing, Monitoring, Inspection & Maintenance of SSCs • In-service Inspection (ISI) • In-service Test (IST) • Reactor Pressure Vessel Surveillance • Instruments Calibration

11. Current Regulations on Life Management • Corrective Actions & Enforcements • Rectification or supplement according to the results of the pre-operational inspection • Rectification or supplement according to the results of the periodic inspections. • Order to take corrective or complementary measures against inadequate performance of facilities and safety measures for the operation • Order to submit report or documents on their business, and order to take corrective or complementary measures as a result of the inspections • Revocation of operating license or suspension of an operation not exceeding one year

12. PSR system • Up-to-date Progress • Nuclear Safety Commission (NSC) decided basic framework for the implementation PSR on December 1999. • MOST issued “Implementing guidelines for PSR” on May 2000, after deliberation of NSC. • KHNP submitted PSR plan for Kori unit 1 on May 2000 • The 1st PSR on Kori unit 1 had been completed by May 2004. (Wolsung unit 1: in progress) • Atomic Energy Act was revised to adopt PSR system on Jan. 2001, including basic direction and framework for the implementation of PSR • Detailed provisions including review scope, method, procedure, and technical standards are included in the Enforcement Decree (Presidential Decree) and the Enforcement Regulation (Ministerial Ordinance) of the Atomic Energy Act.

13. PSR system • PSR Implementing Method • PSR to be carried out every 10 years after issuance of an operating license • KHNP, the operator of NPPs, has the responsibility of performing the PSR • MOST specifies PSR requirements and reviews the PSR results • Review scope is based on the 11 safety factors suggested by IAEA in Safety Series No. 50-SG-O12, and detailed scope may vary depending on plant age • Actual physical condition • of the NPPs • Safety analysis • Equipment qualification • Management of ageing • Safety performance • Use of Experience from other NPPs • & of research findings • Procedures • Organization & administration • Human factors • Emergency planning • ⑪ Environmental impact ☞ The revised IAEA safety guide: Safety Series No. NS-G-2.10 (2003)

14. PSR system • PSR Implementing Method (continued) • The revised IAEA safety guide on PSR of NPPs: • The safety factors were increased from 11 to 14. • The factor, actual physical condition of the NPPs, was subdivided into plant design and actual condition of SSC • The factor, safety analysis, was subdivided into deterministic safety analysis, probabilistic safety analysis (PSA), hazard analysis. • These factors have been reflected in the current regulatory system, but further reinforced regulatory system will be developed. • PSR for twin plants having a single FSAR put together into a single report • Separately consider the ageing of SSCs and the physical status of each plant

15. PSR system • PSR Process • KHNP performs PSR with safety improvements of the plant through hardware or procedural modifications based on the results, and prepares PSR report. • MOST/KINS reviews PSR results and prepares Safety Evaluation Report with identification of safety issues. • MOST with deliberation by NSC makes a decision on whether continued operation is appropriate or not. • Corrective actions are to be issued including PSA, if necessary. • KHNP implements the corrective actions, if any, and prepares “Implementing Report” for the review by MOST/KINS of the results of the corrective actions.

16. PSR Implementing Process KHNP MOST KINS Prepare implementing plan Review implementing plan Review implementing plan • Perform PSR • safety improvements • prepare PSR report Review PSR results Prepare implementing report Review results of corrective actions Review PSR results • Implement corrective actions • perform PSA, if necessary <Deliberation by Nuclear Safety Commission> • Prepare Safety Evaluation Report • identify safety issues Order corrective actions Suspend operation Completion

17. PSR system • Technical Requirements; PSR Review Standards • PSR performed based on technical requirements of reactor facilities and the safety measures for the operation of facilities prescribed under the nuclear legislative and regulatory framework • Detailed technical requirements are referred to those applied to the operating license of a NPP issued near the beginning of the PSR • Exemptions may be possible, if the technical requirements are deemed inappropriate to be applied as they are; • due to the differences in the design principles of a nuclear reactor, or • due to the differences in the operational characteristics of a nuclear reactor • Justification for the exemptions should be provided taking account of physical possibility, safety significance and cost-benefit. • PSA could provide useful insights for the justification

18. PSR system • Technical Requirements; on Ageing Assessment • Review whether plant ageing is being effectively managed so that required safety margins are maintained and whether an adequate ageing management program is in place for future safe operation of the plant. • Classification and selection of SSCs required for the review • Evaluation of ageing mechanism of SSCs • Effect of ageing on functional capability and safety margin of SSCs • Prediction of future state and time-exceeding acceptance criteria of SSCs • Program for ageing management and mitigation of ageing effects

19. PSR system • Technical Requirements; General Technical Criteria • The safety functions of nuclear facilities shall not be impaired by ageing and sufficient safety margin shall be ensured against ageing. • Ageing management program for nuclear facilities shall be established so that safety functions and required safety margins are ensured.

20. Plant Life Management Evaluation Factors • Factors to be Considered for Life Management Principles on the Plant Life Management from IAEA INSAG-14: Safety Management of the Operating Lifetimes of NPP • Consideration of degradation mechanism from the design stage • surveillance, test, inspection, repair and replacement • Comparison with the design basis • Maintaining the design safety level of the plant • Monitoring the effects of ageing and reviewing the life limiting equipment • Assessment of the surveillance results and anticipation of possible repair or replacement work

21. Plant Life Management Evaluation Factors • Review of the reference safety levels • Improvement of reference safety levels as far as reasonably practicable and the preferable achievement by step • Safety review • Effective ageing management and possible evolution of reference safety level • Infrastructure support for safe management • Maintaining sufficient staff with adequate competence • Handling major organization changes to avoid any significant impact on safety • Maintaining excellence in operation by use of self-assessment and peer reviews

22. Plant Life Management Evaluation Factors • Basic factors for Life Management (Life Extension) • Following basic factors, as a tentative, were identified for life management (life extension) considering IAEA principles for operating lifetime management, License Renewal process in the U.S., and practices of plant life extension using PSR in Europe. • Consideration of ageing mechanism in design • Maintenance of design safety level • Upgrading of safety level with current safety standards • Utilization of new technologies and operational experiences • Evaluation and monitoring of ageing • Plan for repair and replacement • Integrated safety review • Evaluation of environmental effects • Infrastructure support fore safe management • Complement of safety-related documents

23. Comparison of Basic Factors for Life Management with PSR & License Renewal

24. Plant Life Management Evaluation Factors • Relation between PSR & Life Management • The basic factors for life management are considered in the current PSR system except following items: • PSA • Evaluation of environmental effects • Complement of FSAR (including TS) in safety-related documents

25. Plant Life Management Evaluation Factors • Comparison with Basic Factors for Life Management • The basic factors for life management were partially considered in the License Renewal process in the U.S., except following items that are considered in the other regulations in 10CFR. • Reflection of Current safety Regulation: Back-fitting Rule (10CFR50.54, f) • Utilization of New Technologies & Operational Experiences: Back-fitting Rule • Plan for Repair & Replacement: Maintenance Rule (10CFR50.65) • Integrated Safety Review: PRA Regulation (10CFR50.34 f, 1, i) • Complement of Safety-related Documents: Maintenance of Record (10CFR50.71)

26. Procedural Requirements for Plant Life Extension • Possible models to be considered • Approval of continued operation through the amendment of operating license • Continued operation with PSR results • Establishment of operating license term For any models, the PSR results can provide useful information for the decision of continued operation.

27. Summary • The PSR system was introduced and well established in the legislative aspects for the comprehensive and systematic safety evaluation of operating plants. • The identified basic evaluation factors were used effectively for the evaluation of the plant life management. • The PSR could be utilized in determining the plant life extension by adding PSA, evaluation of environmental effects and complement of FSAR (including TS) in safety-related documents. • Three possible models for the life management (life extension) of the NPPs were suggested. ※ This study was carried out for the support of the government decision-making to establish the plant life management (life extension).