ML12340A797

Official Exhibit - BRD000001-00-BD01 - Overview of Checworks

ML12340A797
Person / Time
Site:	Indian Point
Issue date:	10/15/2012
From:	Aleksick R, Horowitz J - No Known Affiliation, CSI Technologies
To:	Atomic Safety and Licensing Board Panel
SECY RAS
References
RAS 23613, 50-247-LR, 50-286-LR, ASLBP 07-858-03-LR-BD01
Download: ML12340A797 (13)

Text

United States Nuclear Regulatory Commission Official Hearing Exhibit Entergy Nuclear Operations, Inc.

In the Matter of:

(Indian Point Nuclear Generating Units 2 and 3)

ASLBP #: 07-858-03-LR-BD01 Docket #: 05000247 l 05000286 Exhibit #: BRD000001-00-BD01 Identified: 10/15/2012 Admitted: Withdrawn:

Rejected: Stricken:

Other:

Overview of CHECWORKS Jeffrey S. Horowitz, ScD Robert M. Aleksick Indian Point Energy Center ASLB License Renewal Hearing Presentation Tarrytown, y , New York October 15, 2012 1

=

Background===

Surry Unit 2 accident - December 1986 Demonstrated need to inspect single-phase piping Limited US inspection programs were in place for single-phase FAC In 1987, 1987 EPRI & NUMARC committed to develop a computer program (CHEC) to assist in selecting inspection locations in BWRs and PWRs NUMARC issued d programmatic guidance d including l d use off CHEC or equivalent method.

CHEC later revised and enhanced as CHECWORKS 2

CHEC Development Approach The EPRI CHEC development team gathered data from Europe:

Laboratory data from CEGB (England)

Laboratory data from EDF (France)

Plant and laboratory data from Siemens (Germany)

All known laboratory data were obtained Used limited US plant data U d existing Used i ti scientific i tifi knowledge k l d to t structure t t correlation between piping wear and plant operating parameters EPRI released CHEC 7 months after Surry accident 3

Mathematical Analogue Extending the Keller and the Kastner correlations

& the Berge model, Chexal and Horowitz designed and a d implemented p d a new a algorithm go to obbe u used d in the CHEC program.

FAC Rate = F1

• F2

• F3

• F4

• F5

• F6* F7 Wh Where:

F1 = Temperature factor F2 = Mass transfer factor F3 = Geometry factor F4 = pH factor F5 = Oxygen factor F6 = Allo factor Alloy fa to F7 = Void fraction factor (CHECMATE & CHECWORKS) 4

Improvements Over Previous Approaches CHECWORKS:

Uses a larger database of experimental and plant data.

Incorporates local conditions through water chemistry modeling (pH and dissolved oxygen), void fraction and flow modeling (velocity, pressure and enthalpy).

Uses geometry U t ffactors t ffrom plant l td data t with ith iinsight i ht ffrom copper modeling tests.

CHECWORKS algorithm has been continually validated and refined, as necessary, against new plant and laboratory data.

5

CHECWORKS Input Parameters Heat Balance Diagram - one time input Global plant conditions - power level, thermodynamic conditions, conditions water chemistry and operating time for each operating period Plant component p conditions - component p

geometry, material, size, wall thickness, operating and design conditions, flow rate and quality (if not available from flow analysis)

Component replacement information (if applicable)

Inspection i data d (if applicable) li bl )

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Plant Modeling The plant is divided into a number of lines having roughly the same water chemistry and operating conditionse.g.,

feedwater between feedwater heaters.

Depending on the complexity and amount of resistant material in the plant, there are normally 25 to 50 of these analysis lines.

Using the global information, the wear is calculated for each operating period, and the lifetime wear of each component is calculated by summing up the calculated amounts of wear for each period.

Not all of the lines in a plant are suitable for analysis using CHECWORKS.

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How CHECWORKS Works CHECWORKS is designed to handle:

Changes in operating conditions (e.g., flow rate)

Changes in water chemistry (e.g.,

(e g oxygen concentration)

The two basic design considerations are to:

Model changes g in conditions, including g the abilityy to forecast the impacts of such changes.

Integrates the treatment of inspected and non-inspected components.

CHECWORKS is one tool to help select inspection locations.

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How CHECWORKS Works (cont.)

Pass 1 is an analysis done without considering inspection data.

A Pass 1 analysis is typically used to select initial inspection locations.

The user has the option to include inspection data - this is known as Pass 2.

For Pass 2, the user can compare how well the programs predictions d matchh the h measurements.

Pass 2 predictions go through the center of the p g data (i.e., program is best estimate).

)

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Analyzing Predicted and Observed Data Part of the Pass 2 feedback is the program-computed line correction factor (LCF).

The LCF is computed separately for each Pass 2 line.

The user also can view p predictions versus measurements on various plots and tables allowing the identification and examination of any outliers.

The user then decides whether lines are calibrated or not-calibrated using guidance found in NSAC-202L R3, considering the LCF and other factors factors.

10

Program Outputs For each component, in each line y

analyzed, CHECWORKS p provides:

Predicted wear rate Predicted thickness Predicted time to reach critical thickness For P F Pass 2 analysis, l i CHECWORKS provides the LCF and measured thicknesses 11

Program support EPRI conducts periodic training in FAC issues and the use of CHECWORKS.

EPRI maintains hotline support through a phone line and website.

EPRI sponsors a FAC interest group - CHUG -

which holds two meetings a year.

CHECWORKS is p periodicallyy updated p to meet user feedback.

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Thank you for your attention.

Questions?

End of presentation 13