Status and Prospect of Korean Korea Electric Power Research Institute Core University Program between Japan and Korea on EAC & PSR, 2004.3.26~27, Seoul Status and Prospect of Korean PSR Tae-Ryong Kim (E-mail: trkim@kepri.re.kr) Korea Electric Power Research Institute

Prospect of PSR in Korea Contents Background of PSR Status of PSR in Korea Result of PSR on Kori-1 Prospect of PSR in Korea Conclusion

Background of PSR(1) Chronicle of PSR in Korea ’96.10: IAEA recommended adoption of PSR at Convention on Nuclear Safety ’99.12: Policy for PSR decided by Government ’00.5 : Basic plan of PSR setup by KEPCO ’00.5 : Start of PSR on Kori-1 ’01.7 : Legal system for PSR established ’02.11: PSR report on Kori-1 submitted to MOST ’03.6 : PSR report on Wolsong-1 submitted ’03.12: PSR report on Kori-2 submitted ’04.2 : PSR on other operating NPPs on-going

Background of PSR(2) PSR goals Review what extent the plant meets current safety standards and practices Confirm whether adequate arrangement are in place to maintain plant safety Evaluate safety margin for safe operation in next 10 years Suggest corrective actions to enhance the plant safety

Operation Experience and Research Background of PSR(3) Scope and contents of PSR: 11 Safety factors recommended by IAEA N P P S A F E T Y Actual Condition Aging Management Equipment Qual. Safety Analysis Safe Performance Organ./Admin. Procedures Human Factors Emergency Plan Environment Operation Experience and Research

Background of PSR(4) Legal background of PSR Atomic Energy Act (Article 23 : PSR) PSR Responsibility of NPP Owner Enforcement Decree of the Act (Article 42 : Content of PSR) 11 Safety Factors Enforcement Regulation of the Act (Article 19 : Details of PSR) 55 Detailed Items of Safety Factors Associate Regulatory Guides of MOST Codes & Standards in FSAR

Status of PSR in Korea (1)

Status of PSR in Korea (2) Typical overall procedure of PSR Agreement between Owner/Operator and Regulator Starting Point of PSR Preparation of PSR project Activities of the Regulator PSR Reviews Preparation of the Program of Corrective Actions Approval of an Integrated Program of Corrective Actions End Point of PSR

Status of PSR in Korea (3) Procedure of the Review Set Safety Standard for the Review Define Detailed Scopes and Contents Define Specific Standards for each Safety Factor Deterministic Analysis Propose Corrective Actions Final report Take Immediate Actions Probabilistic Expert Judgement urgent ? Prioritize Corrective Actions

Status of PSR in Korea (4) Cut-off date of the Review Period to be reviewed: from initial criticality to end of the year when the PSR starts Safety standards: 6 months prior to the PSR ends For instance, cut-off date of Kori-1 Period to be reviewed Safety standards used ’77.6.19 Initial Criticality ’00.5.30 PSR start ’00.12.31 ’02.11.30 PSR end ’02.5.31 6 month prior

Status of PSR in Korea (5) Assessment methodologies Basic strategy Adopt methodologies presented in the PSR rules Various methods in accordance with the characteristic of each safety factor Methods used Document review Re-analysis and re-calculation Site walk-down Simulation Questionnaire and interview

Results of PSR on Kori-1(1) Kori Nuclear Unit 1

Results of PSR on Kori-1(2) Actual physical condition of the NPP Determine the adequacy of the plant design, its documentation and actual physical condition of SSC Population density, industrial and traffic facilities around the plant, natural phenomena reviewed Plant improvements up to date Implementation of post-TMI actions Replacement of steam generators, low-pressure rotor, I&C equipment, aged pipes about 1,200m long Installation of remote shutdown panel Current safety standards satisfied Cumulative electricity generated: 89,274GWh 50 heat-ups/cool-downs recorded (designed: 200) SSC: systems, structures & components

Results of PSR on Kori-1(3) Management of ageing Determine whether ageing is being effectively managed and an effective ageing management program is in place Safety-related SSC maintained in good physical condition Current safety standards satisfied RPV integrity confirmed for 40 years or more Fire hazard analysis done Corrective action items recommended Installation of ex-vessel dosimetry Installation of fatigue monitoring system Implementation of Alloy 600 program Upgrade safe shutdown capability against fire

Results of PSR on Kori-1(4) Phase I: Feasibility Study of Continued Operation Prelim. Life Evaluation Economic Analysis Review Regulation . Feasible? by PSR Phase II: Detailed Life Evaluation AMP AMPs Detailed Life Develop Technical Guidelines Field Test Perf. Monitor PLiM DB Regulator’s Review of PSR Results Phase III: Field Implementation of AMPs Y N Revise Input to Aging management of PSR Accept Recommendations Data Collection Screening SSCs

Results of PSR on Kori-1(5) Screening of critical structures and components Screening Criteria based on mainly USA practice License Renewal Rule (10CFR54) Maintenance Rule (10CFR50.65) NRC GALL report Long life, passive components selected Active components included in PSR

Results of PSR on Kori-1(6) 47 Critical structures and components selected and categorized into 12 groups RPV Pressurizer Safety class 1 supports Heat exchanger group Cables Concrete/steel structures Select critical sub-components affecting the integrity and function of structures and components selected Reactor internals Safety class 1 piping Non-safety class 1 piping PV group Distribution panels Underground facilities

Results of PSR on Kori-1(7) Engineering evaluation Most important step in aging management (PLiM) Identify aging mechanisms for the selected groups List generic age-related degradation mechanisms (ARDMs) in each critical sub-component Choose potential ARDMs to a sub-component based on technical rationales

Results of PSR on Kori-1(8) Aging mechanisms in Reactor Pressure Vessel

Results of PSR on Kori-1(9) Evaluate the remaining life of the selected components Reactor pressure vessel for instance Evaluation of pressurized thermal shock Evaluation of irradiation embrittlement Evaluation of upper shelf impact energy Evaluation of fatigue life

Results of PSR on Kori-1(10)

Results of PSR on Kori-1(11) Aging management program (AMP) Review current AMP and other NPP experience Reactor pressure vessel for instance Surveillance test In-Service Inspection per ASME Sec. XI Visual leak inspection Primary water chemistry control Recommend additional AMP Ex-vessel dosimetry Re-evaluation of RTNDT by Master curve method Alloy 600 program, etc

Results of PSR on Kori-1(12) Recommend performance monitoring system for AMP

Results of PSR on Kori-1(13) Summary of PSR results on Kori-1 The safety of Kori Unit 1 re-confirmed Safe operation expected until the next PSR Some corrective action items recommended to enhance the plant safety further Korean unique PSR established

Prospect of PSR in Korea (1) PSR results should be used To confirm the comprehensive safety of a NPP To secure safe operation until the next PSR To identify corrective action items for enhancement of the plant safety further Recommended PSR strategy Initial Criticality PSR 10 years 20 years 30 years Design life + AMP

Prospect of PSR in Korea (2) Operating license terms vs. design life Operating license issued on Unlimited terms (cf. OL of NPP in USA: 40 years) FSAR of Kori Unit 1 describes design life as 30 years (components designed for 40 years) Problem? Regulatory position not established Anti-nuclear party considers design life as OL term End of design life (2008) : not enough to prepare

Prospect of PSR in Korea (3) Regulatory position under consideration for plant life extension PSR could be utilized in determining the plant life extension by adding PSA Evaluation of environmental effects Update of FSAR and TS Introduction of Licensing Renewal rule

Development of PSR Technology National Project Aging management technology ($2.9M) Operational transient analysis and new safety analysis methodologies for NPP ($2.8M) Seismic capacity evaluation of equipment ($2.1M) Environmental radiation monitoring technology ($1.2M) Assessment technology of effect of human and organizational factors on NPP safety ($0.8M) Project Period: Sept. 2000~Feb. 2004 (4 years)

Conclusion PSR with AMP : Very useful tool for long term operation beyond NPP design life PSR – Overall safety review AMP – Aging management program Development of aging management technology to establish AMP should be continued

Thank you for your attention !!