component classification - atoms for peace and … · a critical component.” (inpo ap-913,...

Martin Bridges

Senior Technical Leader – EPRI/NMAC

Event

8-10 September, 2014

Component Classification

2 © 2014 Electric Power Research Institute, Inc. All rights reserved.

Issue Statement

When resources are not focused on critical equipment,

maintenance strategy will be focused on recovering from

failure rather than managing degradation.


Solution

• Right component

• Right work

• Right time


Right Component

300,000


Functional Importance

• Important to safety

• Important to protect the environment

• Important to generation

• Major capital investment


Classification Method

• Develop the classification criteria

• List all of the equipment

• Assemble a team of knowledgeable people

• Perform the process


Classification Criteria

• Regulatory Mandated Maintenance Rules

– United States

– Spain

– Brazil

• Industry Driven Initiatives

– Institute of Nuclear Operations (INPO) & World

Association of Nuclear Operators (WANO)

– Korea Hydro & Nuclear Power (KHNP)


Sample Criteria

• Nuclear Safety Related – Yes or No

• Mitigates an accident or transient – Yes or No

• Could prevent safety related equipment from fulfilling its

function – Yes or No

• Could trip the plant – Yes or No

• Could cause a plant transient – Yes or No

• Used in emergency operating procedures – Yes or No


List of Equipment

• Use a comprehensive list

• Everyone should agree it is the complete list

• Define the owner of each component, usually by system


Assemble Team of Knowledgeable People

• Optimization project representative

• Equipment owner/System Engineer

• Operations knowledgeable person (Senior training

instructor)


Sample Process – System Based

• Schedule an interview

• List the functions

• Screen the functions

• Define a failure

– Degradation

– Alert point

– Action point


Sample Process - Interview

• Interviews controls the schedule

• Interviews gather information effectively

• Interviews keep the process focused

• Sample Questions:

– What does this system do during normal operation?

– What does this equipment do during shutdown

operations?

– What does this equipment do during off-normal

operations?


List Functions

• For each system, list the functions


Screen The Functions

• Using the classification criteria, screen each function

• Once all functions are listed, test each function against

each criterion.

• For each function that matches a criterion, chart the fluid

flow path necessary to perform the function on a flow

diagram.

• Once each qualifying function has been charted, list all of

the equipment that is in the marked flow paths.

• For each function identify what is a loss of function.


Applying the Results

• Consider a tiered approach

• Tiers

– Critical (may have two levels of Critical)

– Non-critical

– Run-to-Maintenance (Failure)


What Is Important - Equipment

• Critical – “if a failure of the component or its structural supports defeats or degrades an important function or a function that is redundant to an important function, then it is a critical component.” (INPO AP-913, Revision 4) Equipment considered necessary for reactor safety or power production. Although equipment may be categorized as critical, not all its components need to be categorized as critical.

• Non-Critical – “a classification of equipment between critical and Run-to-Maintenance for which a cost effective PM makes sense.” (INPO AP-913, Revision 4). Due to the cost benefit achieved and relatively low impact of failure of these components, a limited number of failures should be expected for non-critical components.


Critical Components

• Components in the “Critical” tier require comprehensive testing, increased scrutiny, and may have condition monitoring instrumentation installed. When possible, predictive maintenance testing is typically applied both on-line and off-line.

• Components categorized in the “Critical” tier typically are safety-related and could also have production related criteria.

• The Low Critical tier may require a minimal level of predictive maintenance to assess the overall condition of the component. Components in this tier typically have some or all of the following characteristics:

• May be either safety-related or non-safety-related.

• Failure is undesirable and typically results in an economic effect.

• Some level of preventive and predictive maintenance to enhance reliability and performance is applied.

• Replacement typically cannot be performed on-line.


Non-critical Components

• Components classified in the Non-Critical tier typically

receive some level of preventive maintenance to enhance

their reliability and performance.

Components in this tier typically have some or all of the

following characteristics:

• Typically non-safety-related.

• Failure can result in some economic effect to the plant.

• Accessories can be run-to-maintenance, but themselves

must not be run to mechanical failure.

• Replacements or spare parts are readily available.

• Preventive maintenance tasks are performed to enhance

reliability and performance.


Run-to-Maintenance Components

• Components in this tier typically have some or all of the

following characteristics:

• They are non-safety-related.

• They have low economic affect.

• In-service or unexpected failure is tolerable.

• Preventive maintenance tasks are not cost beneficial with

respect to replacement costs.


Expectations

• Non-critical components should have different expectations

than Critical components

• The Corrective Action Program (CAP) also needs to be in

alignment with these standards to prevent excessive

investigations

• Maintenance of the PM bases should be part of the

established process.

• Changes and deferrals to non-critical PMs should not

require the same level of review as changes to critical PMs,

but the process and expectations for these reviews should

be clearly documented.


Summary

• Attempts to prevent all failures will lead to frustration and

little success.

• Preventive maintenance can help manage degradation, but

it cannot prevent failures.

• Informed classification of components can yield significant

improvement in equipment reliability and reduced

maintenance costs.

component classification - atoms for peace and … · a critical component.” (inpo ap-913,...

Documents