ML071500297

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

ML071500297
Person / Time
Site:	Mcguire, Catawba, McGuire
Issue date:	05/22/2007
From:	Geer T Duke Energy Carolinas, Duke Energy Corp
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML071500297 (6)

Text

THOMAS C. GEER Dkery Vice President Nuclear Engineering Duke Energy Corporation 526 South Church St.

Charlotte, NC 28202 May 22, 2007 Mailing Address:

EC08H / PO Box 1006 U. S. Nuclear Regulatory Commission Charlotte, NC 28201-1006 Washington, D. C. 20555-0001 704 382 4712 Attention: Document Control Desk 704 382 7852 fax tcgeer@duke-energy.corn

Subject:

Duke Power Company LLC d/b/a Duke Energy Carolinas, LLC (Duke)

McGuire Nuclear Station, Units 1 and 2 Docket Numbers 50-369 and 50-370 Catawba Nuclear Station, Units 1 and 2 Docket Numbers 50-413 and 50-414 Report Pursuant to 10 CFR 50.46, Changes to or Errors in an ECCS Evaluation Model

Reference:

Letter from Thomas C. Geer (Duke) to USNRC, "Report Pursuant to 10 CFR 50.46, Changes to or Errors in an ECCS Evaluation Model,"

March 13, 2007 10 CFR 50.46 (a)(3)(ii) requires the reporting of changes to or errors in the Emergency Core Cooling System (ECCS) evaluation models. This report covers the small break loss of coolant accident (SBLOCA) re-analyses recently performed by Westinghouse (at the request of Duke) to support decreased intermediate head safety injection and centrifugal charging pump (IHSI/CCP) flows at all McGuire/Catawba units. The reduced flows were used in the SBLOCA analyses to (1) account for the technical specification surveillance limits of +/-2% on the frequency of the emergency diesel generators (EDGs), and (2) obtain additional test acceptance criteria (TAC) margin for the IHSI and CCP pumps. At the time the potential EDG frequency reduction was discovered, an estimated impact on SBLOCA peak clad temperature (PCT) was not necessary due to sufficient ECCS injected flow margin.

Large break loss of coolant accident (LBLOCA) analyses were not re-analyzed as sufficient low head safety injection (LHSI) flow margin exists in the current analyses to offset the reduced flow due to the frequency reduction of the EDGs.

Implementation of these analyses represents a new SBLOCA analysis of record, and includes the impacts of the NOTRUMP mixing level tracking/region depletion and bubble rise/drift flux model errors. Although implementation of these analyses are voluntary, this report is being issued due to calculated PCT increases of 108 0 F for McGuire Unit 1, 98 0 F for both McGuire Unit 2 and Catawba Unit 1, and 132°F for Catawba Unit 2 versus the final PCT values reported in the above reference.

www. duke-energy. com AoD(

U.S. Nuclear Regulatory Commission May 22, 2007 Page 2 The McGuire and Catawba Updated Final Safety Analysis Reports (UFSARs) will be revised as required by 10 CFR 50.71(e) to reflect these SBLOCA re-analyses following the issuance of this report.

McGuire Units 1 and 2 and Catawba Unit 1 were analyzed separately from Catawba Unit 2 due to steam generator differences. All four plants were analyzed with a break spectrum of 1.5, 2.0, 3.0, and 4.0 inch breaks. A review of the McGuire Units 1 and 2 and Catawba Unit 1 evaluation results shows a limiting PCT of 1323 0 F and maximum transient oxidation of 0.24% for the 2.0 inch break. A review of the Catawba Unit 2 evaluation results shows a limiting PCT of 1243 0 F for the 4.0 inch break and maximum transient oxidation of 0.10% for the 3.0 inch break.

A summary of the SBLOCA PCTs for McGuire Units 1 & 2 and Catawba Unit 1 is provided in Table 1. Table 2 provides a summary of the SBLOCA PCTs for Catawba Unit 2.

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

Sincerely, Thomas C. Geer Attachments Table 1 - SBLOCA Peak Cladding Temperature Summary - McGuire Units 1 & 2 and Catawba Unit 1 Table 2 - SBLOCA Peak Cladding Temperature Summary - Catawba Unit 2

U.S. Nuclear Regulatory Commission May 22, 2007 Page 3 xc: (with attachments)

W. D. Travers, Region II Administrator U.S. Nuclear Regulatory Commission Sam Nunn Atlanta Federal Center, 23 T85 61 Forsyth St., SW Atlanta, GA 30303-8931 J. F. Stang, Senior 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 A. T. Sabisch, NRC Senior Resident Inspector Catawba Nuclear Station

U.S. Nuclear Regulatory Commission May 22, 2007 Page 4 bxc (with attachments)

R. L. Gill - EC05P K. L. Ashe - MG01 RC R. D. Hart - CN01 RC R. A. Hight - EC08H S. B. Thomas - EC08H H. D. Brewer- EC081 K. L. Crane - MG01 RC K. E. Nicholson - CN01 RC Date File - CN01VP NCMPA-1 SREC PMPA NCEMC NRIA File - ELL MNS Master File 801.01- MG01DM CNS Master File 801.01 - CN04DM NED File - E-NRC-LOCA - EC08H

U.S. Nuclear Regulatory Commission May 22, 2007 ATTACHMENTS Table 1 - SBLOCA Peak Cladding Temperature Summary - McGuire Units I & 2 and Catawba Unit I Table 2 - SBLOCA Peak Cladding Temperature Summary - Catawba Unit 2

U.S. Nuclear Regulatory Commission May 22, 2007 Table I SBLOCA Peak Cladding Temperature Summary - McGuire Units 1 & 2 and Catawba Unit I SBLOCA PCT (-F) Comments Evaluation model: NOTRUMP Analysis of record PCT 1323 References A & B 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

References:

A) Westinghouse Report DPC-06-101, "Small Break LOCA Evaluation of Reduced ECCS Flows for McGuire Units 1 & 2 and Catawba Units 1 & 2", December 14, 2006.

B) Westinghouse Letter LTR-LIS-06-453, "10 CFR 50.46 Report for the McGuire Units 1 and 2 and Catawba Units 1 and 2 Reduced ECCS Flow SBLOCA Evaluation", December 19, 2006.

Table 2 SBLOCA Peak Cladding Temperature Summary - Catawba Unit 2 SBLOCA PCT (°F) Comments Evaluation model: NOTRUMP Analysis of record PCT 1243 References A & B 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

References:

A) Westinghouse Report DPC-06-101, "Small Break LOCA Evaluation of Reduced ECCS Flows for McGuire Units 1 & 2 and Catawba Units 1 & 2", December 14, 2006.

B) Westinghouse Letter LTR-LIS-06-453, "10 CFR 50.46 Report for the McGuire Units 1 and 2 and Catawba Units 1 and 2 Reduced ECCS Flow SBLOCA Evaluation", December 19, 2006.