Configuration Management Benchmarking Group Conference June 6 – 9, 2004 Kansas City, MO © 2004...

Configuration Management Benchmarking Group Conference

June 6 – 9, 2004 Kansas City, MO © 2004 CMBG

Deployment of a Margin Model at Comanche Peak

Presented By:

John MeyerTXU Power

TXU Power is not the same company as TXU Electric Delivery and is not regulated by the Public Utility Commission of Texas, and you do not have to buy TXU Power’s products to continue to receive quality

regulated services from TXU Electric Delivery.

TXU Power is not the same company as TXU Electric Delivery and is not regulated by the Public Utility Commission of Texas, and you do not have to buy TXU Power’s products to continue to receive quality

regulated services from TXU Electric Delivery.

Margin Model Deployment at Comanche Peak

Overview of the presentation:

• Background and analysis

• Model design and development

• Implementation – procedure changes and training

• Looking forward


In the beginning…

INPO identified an Area for Improvement:

“During preparation of several modifications and calculations, factors that could influence design and operating margins were not thoroughly identified and evaluated by engineering personnel or effectively communicated to station operators.


Although the station focuses on configuration control when addressing modifications, the impact of changes to design and operating margins is not addressed consistently.”

This AFI was identified during the 2002 E&A which piloted the new Operating Excellence Outcome format


Causes/Contributors identified by INPO:

• A thorough approach to margin impacts was taken in such instances as reactor core and MOV analysis; less consistent behavior was evidenced during less structured activities

• Explicit expectations for margin identification and documentation were not defined


Causes/Contributors (continued):

• Engineering training forums were primarily focused on design requirement and basis documentation issues; additional focus on margins could promote consistent behaviors in margin documentation

• Operations personnel assigned to review modifications could provide insights on actual equipment performance and acceptable operating margins


The AFI Resolution Process:

ADDIE! The Systematic Approach to Life…

• Analyze

• Design

• Develop

• Implement

• Evaluate


Definition of MarginDefinition of Margin

A spare amount or measure or degree allowed or given for contingencies or special situations.

From Webster


An automotive perspective on margin…

The Porsche 911 engine:

• Originally sized at 2.0 liters displacement

• Deliberately designed with a margin sufficient to accommodate possible capacity increases up to about 2.7 liters


Years later, Dr. Ferry Porsche observes:

“Had I known, at that time, that the unit could actually be stretched to 3.3 liters and still be completely reliable, even in racing form, I would almost certainly have decided that it was unnecessarily large and heavy, and would have asked the designers to scale it down. Now I am glad I didn’t!”


Terms of UnderstandingTerms of Understanding

Limits

Failure

Design LimitTech Spec Limit

Safety Margin

Design Margin

Operating Margin

Operating Limit Analytical Margin

Design Allowable

Economic Margin

How do these terms relate to one How do these terms relate to one another or my jobanother or my job??

Ultimate


QuestionsQuestions• Do each of the words have a single definition?• Can a specific combination of two or more

terms mean different things for different circumstances?

• Is this academia or experience based?

• Is there an industry standard or concept to be applied on the use or combined use of these terms?


So what is the difference between the as-analyzed condition and maximum allowable condition?

Margin

Analytical Margin?

Implicit Design Margin?

Explicit Design Margin?

Margin of Circumstances?


The outcome of the “Analysis” stage:

The primary approach to enhancing margin

management at Comanche Peak would be to

develop and implement a Margin Model


The Margin Model Design and

Development Odyssey


Design Requirements

Safety Margins

Design Margins

Operational Margin

Operating Limits

NormalOperations

Safety, Design, and Operational Modeldeveloped by John Maciejewski during CPSES 2002 INPO E&A

Design Capability


The Operating Excellence Outcome and Enablers

[CM-2]Plant activities are

conducted in a manner that maintains configuration control

and operating and design margins

Well-Managed and Understood

Safety, Design, and Operational

Margins

[CM-1]Plant equipment configuration is

maintained consistent with design and

licensing requirements

[CM-3]Processes used to

control plant configuration, design, and licensing bases are clearly defined and implemented

properly


INPO Model - 2003INPO Model - 2003

Operating Point Limit

Normal Operating Point

Design or Tech Spec Basis Limit

Functional/Design Failure

Allowed operating range

Analyzed transient range

Greater than design basis range

Operating margin

Design margin

( Design allows operation in the transient range. However operating restrictions consistent with the design, such as the magnitude and frequency of excursions into this range apply)

( The allowed operating range provides the normal margins operators use without violating setpoints )

( This is a prohibited range of operation and represents the additional conservative margin to account for uncertainties in design and construction )


Functional Failure

Allowable (Design Limit)

Design Basis Limit

Tech. Spec. Limit

Operating Limit

Normal Operation

Safety Margin

AvailableAnalyticalMargin

“Explicit” Design Margin

Licensing / TS Margin

Normal Operating Margin

Functional/Design Failure

Design Failure

Less than Allowable

Results of Analysis

Analyzed Transient Range

Limiting Condition for Operation (LCO) satisfied

Allowed Operating Range

NO Margin

Action Statement

Everything but the Kitchen Sink:


Yet Another Margin Model

Ultimate Capability

Design Allowable Requirements

Design Basis Limit or TS Limit

Operating Limit

Normal Operations

Operating Margin

Design Margin

Safety Margin

Operating Margin


INPO Design Engineering Managers Workshop - August, 2003

• Comanche Peak presented much of the previous material

• Conducted a lengthy afternoon breakout, resulting in a consensus on an appropriate model


Upon return to Comanche Peak:

• Over a period of several weeks, interfaced with a Duke Power group developing a margin model, ultimately merging on concepts philosophically consistent with the INPO workshop consensus

• Corralled Comanche Peak Design Engineering Analysis personnel into a conference room…


• The objective: We don’t leave until we have reached consensus on a Comanche Peak Margin Model

• The process: Summarize previous work, review industry input, share individual opinions, and make a decision

• Two criteria: Simple; portrays Operational, Design, and Safety Margin

• The Design Engineering Analysis Manager’s perspective – Herding Cats

• The result…


CPSES CPSES Margin Margin ModelModel

Ultimate CapabilityUltimate Capability

Design LimitDesign Limit

Operating LimitsOperating Limits

Current OperatingCurrent OperatingConditionsConditions

Safety Safety MarginMargin

DesignDesignMarginMargin

OperationalOperationalMarginMargin


Definitions:

Analytical Margin - Usable Design Margin that is contained within design calculations in the form of conservative methodology, assumptions, and other provisions.

Design Limit - The Design Function acceptance criteria.


Definitions (continued):

Design Margin - That margin between the Operating Limit of a structure, system or component and the Design Limit.

Margin Management - Control of Design Margins and Operating Margins.



Operating Limit - The upper or lower limit of operation of a structure, system or component established by Engineering.

Operating Margin - The difference between the range of normal operation of a structure, system or component and the Operating Limit.



Safety Margin - That margin between the Design Limit and the ultimate capability (i.e., the point at which failure to perform a design function is likely) of a structure, system or component.


Some examples of Model application


Cat. I Structure

Pinch Points: Current Design


Starting Voltage Model


Starting Voltage - Nonconformance

Margin Model Deployment at Comanche PeakStarting Voltage -

New Assumptions


Implementation: Procedure Changes

• Added clarification notes to the overall Design Control procedure

• Added a requirement to the design change procedure to explicitly address operating and design margin considerations in design change engineering bases

• Added a requirement to the calculation procedure to address and document margin considerations in calculations


Implementation: Introductory Training

• Engineering personnel – conducted accredited training for design qualified personnel

• Shift Operations personnel – introduced the model during a Licensed Operator Requalification Training cycle

• Maintenance management – introduced the model via e-mail distribution


Where do we go from here?

• Evaluate effectiveness

• Conduct periodic refresher training

• Train new Engineering and Shift Operations personnel

• Integrate into ongoing configuration management initiatives

• Maintain momentum


Final Perspective

• Margin management must be internalized; this is facilitated by a simple, visual model

• Internalization will reinforce a questioning attitude toward potential margin impacts across the station

• A focus on margin management will promote sensitivity toward station configuration control

Configuration Management Benchmarking Group Conference June 6 – 9, 2004 Kansas City, MO © 2004...

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Transcript of Configuration Management Benchmarking Group Conference June 6 – 9, 2004 Kansas City, MO © 2004...