Development of LCM Technology and. Its Application for PHWR Electrical Components. November 7, 2013

Transcription

1 Development of LCM Technology and Its Application for PHWR Electrical Components November 7, 2013

2 Contents 1. Overview of Life Cycle Management 2. Development of Life Cycle Management Planning Process 3. Application Experience of LCM Planning for PHWR Large Power Transformer 2

3 Definition of Life Cycle Management Life Cycle Management is the integration of aging/obsolescence management and economic planning ; o to optimize the operation, maintenance, and service life of SSC o to maintain acceptance level of performance and safety o to maximize return on investment over the plant service while maintaining Safety. 3

4 Keywords of LCM Keywords of Life Cycle Management Planning = Maintenance + Long Term Plan + Economics = Long Term Planning for Equipment Reliability + Economic Optimization Equipment Reliability Life Cycle Management Nuclear Asset Management Equipment Finance 4

5 Objective of Life Cycle Management Safety Physical Asset Management Improved Plant Condition Engineering Maintenance Aging Management Absolescence LCM Optimum Operating Life Early Retirement Continued Operation Financial Asset Management Maximum Plant Value Increased Revenues Reduced Costs Optimum Resource Allocation Equipment Reliability Nuclear Asset Management 5

6 LCM Planning Process LCM Process consists of three distinct topics : Selection of SSC Step 1 : Selection of SSC for LCM Planning Technical Evaluation Step 2 : SSC Description & Design Characteristic Step 3 : Operating & Maintenance Experience Step 4 : Current Maintenance Activities Step 5 : Aging/Performance/Obsolescence Step 6 : LCM Plan Alternative Economic Evaluation Step 7 : Determination of Failure Rate Step 8 : Economic Evaluation Step 9 : Optimum LCM Plan & Recommendation 6

7 LCM Planning Process 7

8 1. Selection of SSC for LCM Plan 1.1 SSCs Important for LCM Planning 1.2 Determine Appropriate LCM Planning Level Level A Critical SSCs - Warranting In-depth LCM Plans of Special Studies (ex : SG Replacement) Level B Important SSCs and Commodities - Warranting Specific LCM Plan Level C SSCs For Which Existing Maintenance Plans Are Adequate Level D SSCs For Which Formal Maintenance Programs Are Not Required (Run-to-Failure) 8

9 2. SSC Description & Characteristic 2.1 SSC Description Scope, Boundary and Functions The boundaries of the SSC being evaluated are defined List of the assemblies in the system and important components and parts within the assemblies is prepared Summary of the key functional and design requirements for the SSC is compiled 2.2 Design Characteristic System Description Design Parameters 9

10 3. Operating & Maintenance Experience 3.1 Plant Specific Operating Experience Review SSC O&M Experience PM, Inspection & CM History Review SSC Work Order 3.2 Generic Industry Operating Experience Industry History with the same type of plant Gathering Issues & Information for SSCs The goal of these review and comparison is to assess if the SSC s performance can be improved and if the industry experience suggests potential future problems. 10

11 4. Review of Current Maintenance Activities 4.1 Review Current Maintenance Activities Review Current Preventive Maintenance Activities PM Tasks, Task s Interval, Labor Hours & Labor Cost Other Test, Surveillance, CM Activities This review is to assess the effectiveness of the current maintenance program for managing aging degradation over the remaining plant lifetime. 11

12 5. Aging Evaluation 5.1 Feedback based Evaluation Develop comprehensive aging evaluation matrix Include effective aging management program Failure location Degradation mechanism Degradation influence Discovery method Windings Insulation breakdown Heat from overloading or loss of cooling partial discharge testing; winding resistance test 5.2 Theoretical Evaluation Envelope of Failure Probability Curves Physics of Failure 12

13 F(t) 5. Aging Evaluation Concept of Theoretical Approach : Bathtub Curve Maintenance Refurbish Replace Failure Envelope Key failure mechanism Individual failure mechanisms Time Wear-out period Envelope of the Failure Probability Curves

14 6. LCM Plan Alternatives 6.1 Identify Current Issues on the Component 6.2 Develop Alternative LCM Plans to Address the Issues Alternative A : No Changes to Current Maintenance Plan Alternative B : Optimize the Current Maintenance Program Alternative C : Replacement 14

15 7. Economic Evaluation 7.1 Input Value for Economic Evaluation General Input Data Discount Rate, Inflation Rate, Unit Price per MWe etc. Cost Data Preventive Maintenance(PM) Cost Corrective Maintenance(CM) Cost Lost Power Generation(LPG) Cost Historical and Future Failure Rate Data 15

16 7. Economic Evaluation 7.2 Economic Analysis Calculation of Total NPV Cost and B/I Ratio using LEAP Software Total NPV Cost = PM + CM + LPG B/I Ratio = ( CM + LPG) / PM Decision Making Criteria for Selecting optimal LCM Plan The Lowest Total Net Present Value(NPV) Cost The Highest B/I Ratio 16

17 LIFE CYCLE COST Replacement FAILURE PROBABILITY ILCC (Millions) HAZARDRATE 8. Optimal LCM Plan & Recommendation Aging Model Bath Tub Curve ILCC Component Model $39 $38 Run-in Design Life Wearout $37 $36 $35 Optimum Time Of Replacement Base Case COMPONENET LIFE $34 Cost Model $33 $32 Replacement too early Higher Cost due to Forced Outage Year - Integrate the probability of failure from the aging model with costs to determine optimum replacement times. Design Life - The optimum time for replacement or refurbishment will be when the life cycle cost is a minimum. 17 LIFE EXPECTANCY

18 Application Experience for PHWR Electrical Components 18

19 Plant and Selected Components Plant Components Reactor Plant Remark Areas Components Remark Westinghouse Kori Unit 1,2,3,4 YGN Unit 1,2 Mechanical Pumps(MFWP, CCSWP,CWP,AFP,CP) Valves(MFIV,MSIV, MSSV,MFCV) Emergency Diesel Generator Instrument Air Compressor Chiller 6 PWR Moisture Separator Reheater Framatome Ulchin Unit 1,2 Large Transformer Main Generator KSNP YGN Unit 3,4,5,6 Ulchin Unit 3,4,5,6 Electrical Large Motors AC Power Circuit Breaker GIB 5 PHWR CANDU Wolsung Unit 1,2,3,4 I&C Electronic Circuit Module Power Supply 2 (8 Systems)

20 Selected Component and Scope Selected Component Main transformer(mtr) Unit auxiliary transformer(uat) Start-up(Standby) auxiliary transformer(sat) Scope Main transformer Windings, core Bushing, tap-changer Casing, cooler Conservator, transformer oil Other components

21 Selected Component and Scope Selected PHWR Large Transformers Unit Component Name Equipment No. EA Quality Class Wolsung Unit 1 Main Transformer T1 1 EA R Unit auxiliary transformer T1 1 EA R Start up auxiliary transformer T1 1 EA R Wolsung Unit 2 Main Transformer T1 3 EA R Unit auxiliary transformer T1 1 EA R Start up auxiliary transformer T1 1 EA R Wolsung Unit 3 Main Transformer T1 3 EA R Unit auxiliary transformer T1 1 EA R Start up auxiliary transformer T1 1 EA R Wolsung Unit 4 Main Transformer T1 3 EA R Unit auxiliary transformer T1 1 EA R Start up auxiliary transformer T1 1 EA R

22 Operating and Maintenance Experience Results of operating and maintenance experience review Total 45 major O&M experience of large transformers for all the operating units were identified

23 Review of Current Maintenance Activities Preventive maintenance template(main transformer) Condition monitoring task Failure finding task Preventive maintenance task Vibration analysis and sound Level test Transformer casing part vibration Inspection Task interval by FID CHS CLS CHM CLM MHS MLS MHM MLM 3M 3M 3M 3M Y 1Y 1Y 1Y Thermography 3M 3M 3M 3M Dissolved gas analysis(dga) 1Y 1Y 1Y 1Y Oil quality test 1Y 1Y 1Y 1Y Lighting arrestor leakage monitoring 1Y 1Y 1Y 1Y Motor current monitoring 4Y 4Y 4Y 4Y System engineer walkdown 3M 3M 3M 3M Operator rounds 1S 1S 1S 1S Maintenance man inspection 1M 1M 1M 1M Sonic/Ultrasonic noise analysis AR AR AR AR Insulation test AR AR AR AR

24 Aging Evaluation : Qualitative Approach Operating experience based aging evaluation Failure location Degradation mechanism Degradation influence Time code Discovery method Aging evaluation basis operating experience based Transfor mer oil Windings Loss of dielectric strength Dissolved Insulation breakdown Contamination (particulate, water) Arcing, Sparking, partial discharge, over heating Heat from overloading or loss of cooling Aging; normal operating Arcing, sparking, partial discharge, over heating R R W5_7 UW40 R Oil dielectric test; oil quality test; oil power factor testing; DGA, partial discharge detection Power factor, turns ratio test; DGA; furan analysis; partial discharge testing; winding resistance test Analysis result There are similar failure cases of transformers in Wolsung u1,3 unit There are the pssibility of a failure in main transformers of Wolsung 2,3,4 unit that was not replaced Needs additional facilities maintenance strategy There are similar failure cases of transformers in Wolsung 1,3 unit There are the possibility of a failure in main transformers of Wolsung 2,3,4 unit that was not replaced Needs additional facilities maintenance strategy Issue High temperature and generating dissolved gases

25 Aging Evaluation : Quantitative Approach Key Failure Mechanisms Core and internals provide the greatest threat to extended life of transformer Loss of dielectric strength in winding insulation(paper insulation) Characteristic The properties of the winding insulation will change with time and temperature Degradation mechanisms and its stressors of cellulose-based material Key Failure Mechanism - Pyrolysis(heat) - Hydrolysis(water) - Oxidation(Oxygen)

26 Aging Evaluation : Quantitative Approach Quantitative expected life evaluation of large transformer Expected life evaluation using hotspot temperature of winding F 1. Insulation aging rate AA Factor Description FAA kh20 ko2 TH k H 2O k O2 e ( ) 383 T 273 H Insulation aging rate Moisture in paper Oxygen level Hotspot temperature 2. Total equivalent insulation aging factor F Factor FEQA EQA n F AAn n 1 ins n n 1 t t n Description Equivalent Insulation aging factor 3. Loss of life LOL(%) Factor LOL Lins t F EQA t 100 L Description Loss of life Normal insulation life Time Input Data Moisture and oxygen factor [EPRI ] Moisture in paper kh20 Oxygen Level Dry (<0.5%) 1 Low 1 Moist (0.5~2.0%) 2 High 3-5 Wet (>2.0%) 4+ k02 Lins : 180,000h [IEEE ]

27 LCM Plan Alternatives Issue and management strategy for large transformer Unit Component Issues Components management strategy Wolsung Unit 2,3,4 Main transformer High temperature and generating dissolved gas Current preventive maintenance program optimization - Introducing up-to-date condition monitoring system such as on-line partial discharge system and Furan analysis System Equipment improvement(replacement) - Selecting optimized transformer replacement Interval using economic analysis - Improvement of cooling system and condition monitoring system

28 LCM Plan Alternatives Alternative LCM Planning for Large Transformers Unit Component Alternative LCM Plan (40 years operating period) Alternative A Alternative B Alternative C Alternative D Wolsung 2 Main transformer Continuing current program Replacement in 2021 Replacement in 2026 Replacement in 2031 Wolsung 3 Main transformer Continuing current program Replacement in 2022 Replacement in 2027 Replacement in 2032 Wolsung 4 Main transformer Continuing current program Replacement in 2024 Replacement in 2029 Replacement in 2034

29 Economic Analysis Assumptions and Input Value for Economic Analysis No Ex.) Main transformer of Wolsung Uint 2 Maintenance Maintenance Current preventive maintenance Planed preventive maintenance Maintenance Category Cost (Ten thousand won) Failure interval, failure function Continuing current program (Alternative A) Facilities Management Strategy Replacement in 2021 (Alternative B) Replacemen t in 2026 (Alternative C) Replacemen t in 2031 (Alternative D) PM PM Failure maintenance (1] CM 328 Management strategy Constant Constant Replacement RR Loss of power generation Loss of power generation [1] LPG 40[thousand won/mwe-hr] Ⅹ 1,000[MWe] Ⅹ 3.5[hr] Constant Constant [1] Transformer failure rate : Operatiing period 0~30 year (Constant, 1), 30 year~ (Constant, 10)

30 Economic Analysis Result of Economic Analysis for Main Transformer Replacement Unit LCM Plan Alternative of main transformer 40 Years Operating Strategy NPV cost B/I ratio Remark (million won) Alternative A No change to current Program 5,656 - Optimal Wolsung 2 Alternative B Replacement in , Alternative C Replacement in , Alternative D Replacement in , Alternative A No change to current program 4,748 - Optimal Wolsung 3 Alternative B Replacement in , Alternative C Replacement in , Alternative D Replacement in , Alternative A No change to current Program 5,615 - Wolsung 4 Alternative B Replacement in , Alternative C Replacement in , Optimal Alternative D Replacement in ,

31 Economic Analysis Result of Economic Analysis for Main Transformer Replacement Unit LCM Plan Alternative of main transformer 60 Years Operating Strategy NPV cost B/I ratio Remark (million won) Alternative A No change to current Program 8,829 - Wolsung 2 Alternative B Replacement in , Alternative C Replacement in , Optimal Alternative D Replacement in , Alternative A No change to current program 7,650 - Wolsung 3 Alternative B Replacement in , Alternative C Replacement in , Optimal Alternative D Replacement in , Alternative A No change to current Program 8,980 - Wolsung 4 Alternative B Replacement in , Alternative C Replacement in , Optimal Alternative D Replacement in ,

32 Conclusion O&M Experience Aging Obsolcesence PM/CM OE Events Location Mechanism Cause Active Components Work order Report Report Review O&M Data whether improvement is required Feedback based and Theoretical Approach Review of technical obsolcesence Potential O&M issue completed No need Potential Aging Issue Issues to be addressed Existing program and management Satisfied Obsolcesence Issue Alternative LCM Plan Economic Evaluation Intermediate-Long Term Management Strategy

33 Conclusion and Recommendation for Large Power Transformers Large transformer reliability issues are: Monitoring of the oil and insulation quality is paramount to preserving the life of transformer. Although transformers are designed and built for 30 to 40 year service life, operating and maintenance practices can affect their service life span The alternative LCM plans considered include: Implementing diagnostic maintenance which includes thermography and oil analysis Establishing replace program reflecting actual component condition and economic analysis Large transformer LCM Planning identifies component aging mechanisms together with the maintenance activities to manage them as well as optimal replacement time for long term operation

34 Thank You