deployment of a margin model at comanche peak
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Deployment of a Margin Model at Comanche Peak. Presented By: John Meyer TXU Power. - PowerPoint PPT PresentationTRANSCRIPT
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
Margin Model Deployment at Comanche Peak
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.
Margin Model Deployment at Comanche Peak
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
Margin Model Deployment at Comanche Peak
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
Margin Model Deployment at Comanche Peak
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
Margin Model Deployment at Comanche Peak
The AFI Resolution Process:
ADDIE! The Systematic Approach to Life…
• Analyze
• Design
• Develop
• Implement
• Evaluate
Margin Model Deployment at Comanche Peak
Definition of MarginDefinition of Margin
A spare amount or measure or degree allowed or given for contingencies or special situations.
From Webster
Margin Model Deployment at Comanche Peak
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
Margin Model Deployment at Comanche Peak
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!”
Margin Model Deployment at Comanche Peak
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
Margin Model Deployment at Comanche Peak
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?
Margin Model Deployment at Comanche Peak
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?
Margin Model Deployment at Comanche Peak
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
Margin Model Deployment at Comanche Peak
The Margin Model Design and
Development Odyssey
Margin Model Deployment at Comanche Peak
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
Margin Model Deployment at Comanche Peak
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
Margin Model Deployment at Comanche Peak
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 )
Margin Model Deployment at Comanche Peak
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:
Margin Model Deployment at Comanche Peak
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
Margin Model Deployment at Comanche Peak
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
Margin Model Deployment at Comanche Peak
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…
Margin Model Deployment at Comanche Peak
• 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…
Margin Model Deployment at Comanche Peak
CPSES CPSES Margin Margin ModelModel
Ultimate CapabilityUltimate Capability
Design LimitDesign Limit
Operating LimitsOperating Limits
Current OperatingCurrent OperatingConditionsConditions
Safety Safety MarginMargin
DesignDesignMarginMargin
OperationalOperationalMarginMargin
Margin Model Deployment at Comanche Peak
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.
Margin Model Deployment at Comanche Peak
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.
Margin Model Deployment at Comanche Peak
Definitions (continued):
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.
Margin Model Deployment at Comanche Peak
Definitions (continued):
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.
Margin Model Deployment at Comanche Peak
Some examples of Model application
Margin Model Deployment at Comanche Peak
Cat. I Structure
Pinch Points: Current Design
Margin Model Deployment at Comanche Peak
Starting Voltage Model
Margin Model Deployment at Comanche Peak
Starting Voltage - Nonconformance
Margin Model Deployment at Comanche PeakStarting Voltage -
New Assumptions
Margin Model Deployment at Comanche Peak
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
Margin Model Deployment at Comanche Peak
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
Margin Model Deployment at Comanche Peak
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
Margin Model Deployment at Comanche Peak
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