Maintenance Optimization: A Critical Aspect of the Equipment Reliability Program

Transcription

1 Maintenance Optimization: A Critical Aspect of the Equipment Reliability Program Russ Warren, INPO IAEA, Vienna October 2011

2 Process Overview FEGs and Crit. for Work Management To Work Management To Budgeting Process Corporate Nuclear Asset Management Strategic Planning Maintenance Feedback Functional Equipment Groups and Functional Importance Determination + Performance + = Monitoring Plans Maintenance (PMP) Optimization (MO) Long Term Plan (LTP) Work Implementation (AP-928) Component Criticality Plant and system Performace Risks PM Task Scope, Justification and Frequency Post Maintenance Test Budgeting Process Single Point Failure Study Mitigation Strategies Risk Ranking Options Identification and Selection PM Options for Solving Health Risk Justification No PM Required" Enablers * Operating Experience * Industry baseline programs (EPRI) * Experienced people * Computer Tools Decisions Related to What to Do Decisions Related to How to Do

3 Core Processes Data Management Functional Equipment Groups (FEG) to Support Automated Work Scheduling Criticality Determination Single Point Failure Vulnerability Critical Components and Critical Spares Performance Monitoring Plan (PMP) Development and Monitoring Maintenance Optimization (MO) Long Term Plan Development Corrective Action Program Maintenance Feedback

4 Maintenance optimization Objectives of NPP maintenance optimization Maintenance optimization requirements and maintenance Key elements of maintenance optimization programmes Performance indicators 2011 Institute of Nuclear

5 FEG - What is a FEG? Process Flow Motor Breaker Loss of this instrument will not cause a loss of function. AA A Motor and Pump FEG Boundary AA A The FEG boundary equipment becomes the 'standard' clearance tag-out for this FEG. Cooling Flow Fan Breaker Air Flow Heat Exchanger This Room Cooler is included in the FEG because a loss of the Cooler will cause a loss of the function of the FEG.

6 Criticality Determination Identify those components most critical to plant safety and reliability Used to allocate resources Used to prioritize work

7 Critical component failures cause significant power transient or derate loss of a redundant safety function unplanned entry into a technical specification LCO half scram or partial trip reactor shutdown actuation of emergency safeguards features 2011 Institute of Nuclear

8 Critical component failure cause failure to control a critical safety function such as reactor water level and pressure, primary and secondary containment, drywell temperature and pressure, or spent fuel pool temperature and level degraded capability to shut down the reactor and maintain it in a shutdown condition inability to perform an emergency operating procedure, or to prevent or mitigate the consequences of accidents that could result in potential off-site exposure in excess of 10CFR100 limits; operator workaround operator workaround for performing any of the above functions or procedures Institute of Nuclear

9 Sample Criticality Analysis Results components reviewed Crit 1 = 13331, or 22% (SR) Crit 2 = 26462, or 43% (Important) Crit N = 21494, or 35% (Run to failure) Effort 22 Weeks 4400 Consultant Man-Hours 2100 Internal Man-Hours

10 Single Point Vulnerability Study CRITERIA: A SPV exists if failure of a single component results in: Reactor Trip, or Turbine Trip, or Generator electrical power output reduction > 5%. (Note: Initial condition 100% power)

11 Most Significant Components Affecting Unit Reliability - As Derived from SPV Studies Air-operated valves Emergency diesel generator - electrical Main feedwater pump Main generator and support systems (Not listed in order of importance)

12 Non-critical component Component failure creates an unacceptable increase in personnel, industrial, environmental, or radiological safety hazard. The component has a history of unacceptably high repair, replacement, or operational cost. Component failure represents an operator or maintenance burden. The component is obsolete, in short supply, or very expensive to repair or replace. There is a long lead time for replacement parts, which prevents a required component from being repaired in a timely fashion. The component is necessary for work on critical equipment (for example, isolation valve) Institute of Nuclear

13 Non-critical component Component failure promotes failure of other components. There is a potential for new risks from hazardous chemicals or environmental concerns. Failure results in a power transient, sustained generation loss, or reduction in the necessary redundancy or defense in-depth. Failure may lead to regulatory consequences. Component failure will hamper or prevent timely repair of a critical component. It is more cost-effective to maintain the component, as opposed to repair or replacement.

14 Run to failure components A run-to-failure component is one for which the risks and consequences of failure are acceptable without any predictive or repetitive maintenance being performed and there is not a simple, cost-effective method to extend the useful life of the component. The component should be run until corrective maintenance is required Institute of Nuclear

15 Performance Monitoring Typical Equipment Reliability Program Criticality Determination: * Equipment Importance * Basis * Duty * Environment Functional Equipment Group (FEG): * Boundaries * Equipment In Boundary * Characteristic Information Required Levels of Performance : * Reliability (Functional Failures) * Unavailability * Cost * Basis for Levels of Performance Operating Rounds: (MO) * Sight * Smell * Feel * Hear Breaker * Plant Computer - Number of Breaker Cycles * Plant Computer - With Flow, Calculate Run Time * PM - Disassembly and Inspection * PM - Overhaul * PdM - Thermography Recorded Parameters : (PMP) * Plant Operating Logs - in band * Plant Operating Logs - trended * Plant Computer - in band * Plant Computer - trended Engineering : * Walk-down Inspection * Operational Performance * Problem Resolution * Trends in Performance * System and Component Health Reports Pressure Instrument * Operating Log - Discharge Pressure within Band * PM - calibration (In a Calibration FEG) AA A Flow Instrument * Plant Computer - calculate run time, ID degraded flow * PM - calibration Time or Condition Based Repetitive Maintenance: (MO) * Preventive Maintenance (PM) * Predictive Maintenance (PdM) * Planned Maintenance * List Surveillance Test Procedures (STPs) * Basis for Repetitive Maintenance Motor Operated Valve * PM - External Inspection * PM - Stem Lubrication * PdM - Gear Case Lubrication Sample * VOTES / MOVATS Testing * PM - Sample Switch Case Lubricant Manual Valve * Run to Failure Pump * PdM - Vibration Monitoring * PdM - Oil Sample * STP - Performance Test * Operations - Periodic Rotation of Redundant Equipment Motor * PdM - Vibration Monitoring * PdM - Oil Sample * PdM - Motor Circuit Analysis * PdM - Motor Current Analysis * PdM - Motor Insulation Temperature * PM - Sample Inspection of Motor Population Check Valve * PdM Acoustic Monitoring * PM - Sample Inspections Operate: * Operate per Procedures * Configure Plant for Maintenance Recirc Pressure * Run to Failure AA A Manage Performance: * One-button trending and analysis * Automatic Gap Identification * Expert Cause Analysis * Expert Options Identification and Decision Making * Follow-up to Ensure Effectiveness Manage Work: * Current Life-cycle Plan * Schedule Work to Manage Risk and Greatest Efficiency * Schedule then Plan Work Procure: * Supply quality -level parts to meet schedule and breakdown demands FEG Boundary and Characteristic Information Maintain: * Efficient and Quality Maintenance and Post Maintenance Test * Documentation * Feedback / Recommendations for Improvement Train / Develop People: * All personnel are expert at what they do

16 Maintenance Optimization Apply resources to those components most important to plant safety and reliability Remove resources from those components that have minimal impact on safety and reliability and whose loss can be tolerated or can be replaced easily

17 Maintenance Optimization Corrective maintenance Preventive maintenance (3 types) Periodic servicing, parts, time based Predictive monitoring, non-intrusive, analysis Planned scheduled replacement or refurbishment to prevent failure 2011 Institute of Nuclear

18 PM Change Implementation Process Overview Planning Support Activities MO Evaluation Results (PM Basis, Changes to the PM Program and if Applicable, PMCR) Categorize PM Changes and Develop PM Change Implementation Plan - Deleted and Superseded PM's - PM Frequency Change - Components added to PMs - Changes to PM Scope - New PM's Develop PM Change Implementation Plan WO Planning - PM Activity Deletions - PM Frequency Changes - Model Work Order Development and Changes - Model Work Instruction Development and Changes - Requests for Planning Support Activities Performance Monitoring - New monitoring requirements Supply Chain - New parts - Obsolete parts - Obsolescence strategy Maintenance - New maintenance practices - New tools - New test equipment PM Change Scheduling - Establish or Revise Schedule Dates - Close or Modify Active Work Orders Assess Effectiveness of PM Changes - The effectiveness of PM changes will be evaluated through the Performance Monitoring / Health Reports Training - Training for new tasks - Training for new tools - Training for new test equipment PM Implementation Considerations - Prioritize changes - Consider criticality, as found conditions, aggregate risk - Implement easy changes first - Stagger implementation of large changes - start long lead items early - Ensure proper sequencing of changes, such as in superseded PM activities - Ensure new schedule dates are aligned with FEGs or system / train schedule - Adhere to outage freeze milestones - Perform risk assessments - Integrate with the Work Management Look Ahead process Post Maintenance Test - New or Modified Test Requirements Procedures and Instructions - New or Modified Procedures

19 Sample Maintenance Optimization (MO) Results 33 Component Type Basis Documents Created 4577 PM change requests initiated Effort Required 38 Weeks 5700 Consultant Man-Hours 2400 Internal Man-Hours

20 Sample MO Implementation Results 3897 PM change requests implemented 680 PM change requests in progress Effort Required 78 Weeks 9100 Consultant Man-Hours 5500 Internal Man-Hours

21 Living process Performance Feedback Periodic PM and work order condition reviews provide routine feedback to the PM process to adjust PM frequencies and scope. Analysis of corrective maintenance work considers whether PM was adequate or should be modified, or new PMs should be added.

22 Living process Review Equipment reliability process is a living process. Although a considerable effort is committed to perform the optimization, ongoing work is needed using the same tools and methods. The PM review team typically meets routinely to review PM program changes or additions. Work scope team meets weekly to review upcoming planned PMs (week T-16 to T- 26)

23 Long-Term Plan Generation / revenue plan Design planning and implementation Outage cycle plans Unit refurbishment or major component replacement (reactor vessel head, steam generator, major cabling) Equipment refurbishment (turbine overhauls, motors, large transformers)

24 Life-Cycle Management What are the estimated remaining lives of the following kinds of components? Reactor coolant/recirc pump motors? Buried piping? Buried cabling? Main transformers? Main generators?

25 Life-Cycle Management (con t) What data is available to estimate their lifetime? What strategies are available to prolong their life? What are the industry/vendors doing to estimate or test for remaining life? When is the most economical time to change them? (coordinate with other major work but limit budget impact long range plan)

26 Example: Generator Life Expectancies Component OEM Design Retaining Rings Exciters/AVRs Rotor Windings Rotor Forging Expected Life approx. 30 years years years years years

27 Sources of Life Expectancy Data LCM Sourcebooks Issued for 14 component/systems: buried piping, breakers, condenser, ESW, FW heaters & controls, IA, generator, turbine Some LCM plans are based on engineering practice and are less rigorous

28 Questions????