ML101670089

Stations, Units 1 and 2 - Report Pursuant to 10 CFR 50.46, Changes to or Errors in an ECCS Evaluation Model

ML101670089
Person / Time
Site:	Catawba
Issue date:	06/10/2010
From:	Geer T Duke Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML101670089 (6)

Text

Thomas C. Geer Duke Vice President

aEnergy, 10 CFR 50.46 Nuclear Engineering Duke Energy Corporation 526 South Church Street Charlotte, NC 28202 Mailing Address:

ECOH I P. 0. Box 1006 Charlotte, NC 28201-1006 7043824712 June 10, 2010 704 382 7852 fax U. S. Nuclear Regulatory Commission Tom. Geer@duke-energycom Washington, D. C. 20555-001 Attention: Document Control Desk

Subject:

Duke Energy Carolinas, LLC (Duke Energy)

McGuire Nuclear Station, Units 1 and 2 Docket Number 50-369 and 50-370 Catawba Nuclear Station, Units 1 and 2 Docket Number 50-413 and 50-414 Report Pursuant to 10 CFR 50.46, Changes to or Errors in an ECCS Evaluation Model 10 CFR 50.46 (a)(3)(ii) requires the reporting of errors or changes in the Emergency Core Cooling System (ECCS) evaluation models (EMs). This report covers the time period from January 1, 2009 to December 31, 2009.

During this time period, there were no errors or evaluation model changes identified by Westinghouse that exhibited changes to the peak cladding temperature (PCT) results.

However, three non-discretionary changes were made to the Large Break Loss of Coolant Accident (LBLOCA) EM. The specific details of these-changes are provided in Table 1, and were not considered to have an impact on the calculated PCTs. Since there was no PCT_

impact due to these non-discretionary changes, they are not included in the PCT summary tables.

For completeness, Westinghouse also informed Duke Energy of a number of discretionary coding changes that were made as part of normal code maintenance and general code cleanup for the LBLOCA analyses. Specific details of these changes are also provided in Table 1 and were not considered to have an impact on the calculated PCTs. As such, they are not included in the PCT summary tables.

All McGuire and Catawba units were loaded with cores comprised entirely of Westinghouse fuel for the calendar year 2009. Therefore, no transition core PCT penalties are included in the PCT summary tables.

A summary of the PCT changes for McGuire Units 1 and 2 and Catawba Unit 1 is provided in Table 2, and Table 3 provides a summary of the PCT changes for Catawba Unit 2.

www.duke-energy.com

U.S. Nuclear Regulatory Commission June 10, 2010 Page 2 There are no regulatory commitments associated with this letter.

Please address any comments or questions regarding this matter to L. B. Jones at (704) 382-4753.

Sincerely, Thomas C. Geer Vice President, Nuclear Engineering Attachments, Table 1 - Errors/Evaluation Model Changes with no PCT Impact Table 2 - Peak Cladding Temperature Summary - McGuire Units 1 & 2 and Catawba Unit 1 Table 3 - Peak Cladding Temperature Summary - Catawba Unit 2 xc: (with, attachments)

L. A. Reyes, Region II Administrator U.S. Nuclear Regulatory Commission Marquis One Tower 245 Peachtree Center Avenue NE, Suite 1200 Atlanta, GA 30303-1257 J. H. Thompson, Project Manager (CNS & MNS)

U. S. Nuclear Regulatory Commission 11555 Rockville Pike Mail Stop 0-8 G9A Rockville, MD 20852-2738 J. B. Brady, NRC Senior Resident Inspector McGuire Nuclear Station G. A. Hutto, III NRC Senior Resident Inspector Catawba Nuclear Station

ATTACHMENTS Table 1 - Errors/Evaluation Model Changes with no PCT Impact Table 2 - Peak Cladding Temperature Summary - McGuire Units 1 & 2 and Catawba Unit 1 Table 3 - Peak Cladding Temperature Summary - Catawba Unit 2 Page 1

Table 1 Errors / Evaluation Model Changes with no PCT Impact Discretionary Changes:

General Code Maintenance (BELOCA 1996 Model)

Various changes were made to enhance the usability of the codes and to streamline future

.analyses. Examples of these changes include modifying input definitions, units and defaults, improving the input diagnostic checks; enhancing the code output; optimizing active coding; and eliminating inactive coding. The nature of these code changes leads to an estimated PCT impact of 0 °F.

Non-Discretionary Changes:

Discrepancy in Metal Masses Used from Drawinqs (BELOCA 1996 Model)

Discrepancies were discovered in the use of lower support plate (LSP) metal masses from drawings. The updated LSP metal masses have been evaluated for impact on current licensing-basis analysis results and will be incorporated on a forward-fit basis. The lower support plate mass error is relatively minor and is estimated to have a negligible effect on the Large Break LOCA analysis results. Therefore, the estimated PCT impact of this error is 0 °F for 10 CFR 50.46 reporting purposes.

HOTSPOT Gap Heat Transfer Logic (BELOCA 1996 Model)

The HOTSPOT code has been updated to incorporate the following changes to the gap transfer, logic: (1) change the gap temperature from the pellet average temperature to the average of the pellet outer surface and cladding inner surface temperatures; (2) correct the calculation of the pellet surface emissivity to use a temperature in °R (as specified in Equation 7-28 of WCAP-12945-P-A, Volume 1, Revision 2) instead of 'F; and (3) revise the calculation of the gap radiation heat transfer coefficient to delete a term and temperature adder not shown in or suggested by WCAP-1 2945-P-A, Volume 1, Revision 2. Sample calculations showed a minimal impact on PCT, leading to an estimated effect of 0 *F.

HOTSPOT Statistical Output Logic (BELOCA 1996 Model)

The HOTSPOT code has been updated to incorporate the following changes to the statistical logic for calculations using the Code Qualification Document methodology: (1) revise one of the three methods for calculating the standard deviation of cladding temperature to correctly identify the bin containing the 9 7.5th percentile value; and (2) change the 5 0 th, 9 5th and 97. 5 th percentile bin values from the lower end of the range to the upper end. Sample calculations suggested a minimal impact on the 9 5 th percentile PCT, leading to an estimated effect of 0 *F.

Page 2

Table 2 Peak Cladding Temperature Summary - McGuire Units 1 & 2 and Catawba Unit 1.

LBLOCA Cladding Temp (TF)

Comments Evaluation model : WCOBRA/TRAC, CQD 1996 MNS/CNS Analysis of record PCT 2028 Composite Model Prior errors (APCT)

1. Decay heat in Monte, Carlo calculations 8

Reference A

2. MONTECF power uncertainty correction 20 Reference B

3. Safety Injection temperature range 59 Reference C

4. Input error resulting in an incomplete solution matrix 25 Reference D

5. Revised Blowdown Heatup Uncertainty Distribution 5

Reference E

6. Vessel Unheated Conductor Noding 0

Reference F Prior evaluation model changes (APCT)

1. Revised Algorithm for Average Fuel Temperature 0

Reference F Errors (APCT)

1. None 0

Evaluation model changes (APCT)

1. None 0

Absolute value of errors/changes for this report (APCT) 0 Net change in PCT for this report 0

Final PCT 2145 SBLOCA Evaluation model: NOTRUMP Analysis of record PCT 1323 2 inch break Prior errors (APCT)

1. None 0

Prior evaluation model changes (APCT)

1. None 0

Errors (APCT)

1. None 0

Evaluation model changes (APCT)

1. None 0

Absolute value of errors/changes for this report (APCT) 0 Net change in PCT for this report 0

Final PCT 1323

Reference:

A) letter, M. S. Tuckman (Duke) to USNRC, "Report Pursuant to 10 CFR 50.46, Changes to or Errors in an ECCS Evaluation Model", May 3, 2001 B) letter, M. S. Tuckman (Duke)'to USNRC, "Report Pursuant to 10 CFR 50.46, Changes to or Errors in an ECCS Evaluation Model", April 3, 2002 C) letter, W. R. McCollum, Jr. (Duke) to USNRC, "Report Pursuant to 10 CFR 50.46, Changes to or Errors in an ECCS Evaluation Model", July 29, 2003 D) letter, W. R. McCollum, 'Jr. (Duke) to USNRC, "Report Pursuant to 10 CFR 50.46, Changes to or Errors in an ECCS Evaluation Model", May 26, 2004 E) letter, J. R. Morris (Duke) to USNRC, "Report Pursuant to 10 CFR 50.46, Changes to or Errors in an ECCS Evaluation Model", June 21, 2005 F) letter, T. C.:Geer (Duke) to USNRC, "Report Pursuant to 10 CFR 50.46, Changes to or Errors in an ECCS Evaluation Model", March 13, 2007 Page 3

Table 3 Peak Cladding Temperature Summary - Catawba Unit 2 LBLOCA Cladding Temp (OF)

Comments Evaluation model: WCOBRA/TRAC, CQD 1996 MNS/CNS' Analysis of record PCT 2028 Composite Model Prior errors (APCT)

1. Decay heat in Monte Carlo calculations 8

Reference A

2. MONTECF power uncertainty correction 20 Reference B

3. Safety Injection temperature range 59 Reference C

4. Input error resulting in an incomplete solution matrix 25 Reference D

5. Revised Blowdown Heatup Uncertainty Distribution 5

Reference E

6. Vessel Unheated Conductor Noding 0

Reference F Prior evaluation model changes (APCT)

1. Revised Algorithm for Average Fuel Temperature 0

Reference F Errors (APCT)

1. None 0

Evaluation model changes (APCT)

1. None 0

Absolute value of errors/changes for this report (APCT) 0 Net change in PCT for this report 0

Final PCT 2145 SBLOCA Evaluation model.: NOTRUMP Analysis of record PCT 1243 4 inch break Prior errors (APCT)

1. None' 0

Prior evaluation model changes (APCT)

1. None 0

Errors (APCT)

1. None

-0 Evaluation model changes (APCT)

1. None 0

Absolute value of errors/changes for this report (APCT) 0 Net change in PCT for this report 0

Final PCT 1243

Reference:

A) letter, M. S. Tuckman (Duke) to USNRC,."Report Pursuant to 10 CFR 50.46, Changes to or Errors in an ECCS Evaluation Model", May 3, 2001 B)* letter, M. S. Tuckman (Duke) to USNRC, "Report Pursuant to 10 CFR 50.46, Changes to or Errors in an

'ECCS Evaluation Model", April 3, 2002 C) letter, W. R. McCollum, Jr. (Duke) to USNRC, "Report Pursuant to 10 CFR 50.46, Changes to or Errors in an ECCS Evaluation Model", July 29, 2003 D) letter, W. R. McCollum, Jr. (Duke) to USNRC, "Report Pursuant to 10 CFR 50.46, Changes to or Errors in an ECCS Evaluation Model", May 26, 2004 E) letter, J. R. Morris (Duke) to USNRC, "Report Pursuant to 10 CFR 50.46, Changes to or Errors in an ECCS Evaluation Model", June 21, 2005 F) letter, T. C. Geer (Duke) to USNRC, "Report Pursuant to 10 CFR 50.46,.Changes to or Errors in an ECCS Evaluation Model", March 13, 2007 Page 4