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2011 World Association of Nuclear Operators
Maintenance Optimization:
A Critical Aspect of the
Equipment Reliability
Program
Russ Warren, INPO
IAEA, Vienna
October 2011

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

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

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

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

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

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
Power
Operatio
ns

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.
2011
Institute
of
Nuclear
Power
Operatio
ns

Sample Criticality Analysis Results
61287 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

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)

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)

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). 2011
Institute
of
Nuclear
Power
Operatio
ns

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.

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.
2011
Institute
of
Nuclear
Power
Operatio
ns

Performance Monitoring
Pressure Instrument
* Operating Log - Discharge Pressure
within Band
* PM - calibration
(In a Calibration FEG)
AA
A
Typical Equipment Reliability Program
FEG Boundary and Characteristic
Information
Operating Rounds:
(MO)
* Sight
* Smell
* Feel
* Hear
Engineering :
* Walk-down Inspection
* Operational Performance
* Problem Resolution
* Trends in Performance
* System and Component
Health Reports
Recorded Parameters : (PMP)
* Plant Operating Logs - in band
* Plant Operating Logs - trended
* Plant Computer - in band
* Plant Computer - trended
Required Levels of
Performance :
* Reliability
(Functional Failures)
* Unavailability
* Cost
* Basis for Levels of
Performance
Manual Valve
* Run to Failure
Breaker
* Plant Computer - Number of
Breaker Cycles
* Plant Computer - With Flow,
Calculate Run Time
* PM - Disassembly and Inspection
* PM - Overhaul
* PdM - Thermography
Check Valve
* PdM Acoustic
Monitoring
* PM - Sample
Inspections
Flow Instrument
* Plant Computer - calculate run
time, ID degraded flow
* PM - calibration
Pump
* PdM - Vibration Monitoring
* PdM - Oil Sample
* STP - Performance Test
* Operations - Periodic Rotation of
Redundant Equipment
Operate:
* Operate per Procedures
* Configure Plant for
Maintenance
Time or Condition Based
Repetitive Maintenance: (MO)
* Preventive Maintenance (PM)
* Predictive Maintenance (PdM)
* Planned Maintenance
* List Surveillance Test
Procedures (STPs)
* Basis for Repetitive
Maintenance
Maintain:
* Efficient and Quality
Maintenance and Post
Maintenance Test
* Documentation
* Feedback /
Recommendations for
Improvement
Manage Work:
* Current Life-cycle Plan
* Schedule Work to Manage Risk
and Greatest Efficiency
* Schedule then Plan Work
Criticality Determination:
* Equipment Importance
* Basis

Documents

Maintenance Optimization: A Critical Aspect of the ... · PDF fileMaintenance Optimization: A Critical Aspect of the ... –Generator electrical power output reduction > ... (Not listed