ML15233A024

Transmittal of Annual Report of Loss-of-Coolant Accident Evaluation Model Changes

ML15233A024
Person / Time
Site:	Cook
Issue date:	08/19/2015
From:	Lies Q Indiana Michigan Power Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
AEP-NRC-201 5-79
Download: ML15233A024 (7)

Text

z INDIA NA MICHIGAN P0OWERE A unit of American Electric Power Indiana Michigan Power Cook Nuclear Plant One Cook Place Bridgman, Mi 49106 IndianaMichigan Power~com AEP-NRC-201 5-79 10 CFR 50.46 August 19, 2015 Docket Nos.: 50-315 50-316 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Donald C. Cook Nuclear Plant Units 1 and 2 ANNUAL REPORT OF LOSS-OF-COOLANT ACCIDENT EVALUATION MODEL CHANGES Pursuant to 10 CFR 50.46, Indiana Michigan Power Company (I&M),

the licensee for Donald C. Cook Nuclear Plant (CNP), is transmitting an annual report of loss-of-coolant accident (LOCA) evaluation model changes affecting the peak cladding temperature (PCT) for CNP Unit 1 and Unit 2. I&M is providing, as an enclosure to this letter, the Unit I and Unit 2 Large Break and Small Break LOCA Analyses-of-Record PCT values and error assessments for calendar year 2014.

There are no new or revised commitments in this letter. Should you have any questions, please contact Mr. Michael K. Scarpello, Regulatory Affairs Manager, at (269) 466-2649.

Sincerely, q~tn S. Lies Engineering Vice President JMT/ams

Enclosure:

Donald C. Cook Nuclear Plant Units 1 and 2, Large and Small Break Loss-of-Coolant Accident Peak Clad Temperature Summary c:

A. W. Dietrich, NRC Washington, D.C.

J. T. King, MPSC MDEQ - RMD/RPS NRC Resident Inspector C. D. Pederson, NRC Region Ill A. J. Williamson, AEP Ft. Wayne, w/o enclosure

ENCLOSURE TO AEP-NRC-2015-79 DONALD C. COOK NUCLEAR PLANT UNITS I AND 2 LARGE AND SMALL BREAK LOSS-OF-COOLANT ACCIDENT PEAK CLAD TEMPERATURE

SUMMARY

Abbreviations:

ADAMS Agencywide Document Access and Management System CNP Donald C. Cook Nuclear Plant

°F degrees Fahrenheit ECCS emergency core cooling system EM evaluation methodology FdH nuclear enthalpy rise hot channel factor EQ heat flux hot channel factor I&M Indiana Michigan Power Company LBLOCA large break loss of coolant accident LOCA loss of coolant accident MWt megawatts - thermal NRC U. S. Nuclear Regulatory Commission PBOT power limit at bottom part of reactor PCT peak cladding temperature percent PMID power limit at middle part of reactor SGTP steam generator tube plugging TCD thermal conductivity degradation Summary:

By letter dated March 19, 2012, (ADAMS Accession No. ML12088A104), and supplemented by letter dated June 11, 2012 (ADAMS Accession No. ML12173A025), I&M, the licensee for CNP Units 1 and 2, submitted a report describing the impact of fuel pellet TCD on the LBLOCA ECCS evaluation model, and an estimate of the effect on the predicted PCT for CNP Units 1 and 2. This report was submitted pursuant to 10 CFR 50.46(a)(3), and referred to a letter from Westinghouse Electric Company dated March 7,

2012 (ADAMS Accession No. ML12072A035). The report was subsequently found to be acceptable by NRC letter dated March 7, 2013 (ADAMS Accession No. ML13077A137).

By letter dated August 30, 2013 (ADAMS Accession No. ML13247A174), l&M submitted a report describing the impact of Revised Heat Transfer Multiplier Distributions on the predicted PCT for CNP Unit 1.

This report was submitted pursuant to 10 CFR 50.46(a)(3).

By Westinghouse letter LTR-LIS-13-360, "D. C. Cook Units 1 and 2 10 CFR 50.46 Report for Revised Heat Transfer Multiplier Distributions," dated July 31, 2013, Westinghouse Electric Company notified I&M of significant errors in the EM for the LBLOCA analysis of record for CNP Unit 1. By Westinghouse letter LTR-LIS-13-406, "Additional Information on the Evaluation of Revised Heat Transfer Multiplier Distributions," dated August 14, 2013, Westinghouse Electric Company provided I&M additional detail on the nature of the errors and the corrections made.

Enclosure to AEP-NRC-2015-79 Page 2 As documented in the subsequent rack-up sheets, the error results in a benefit to the calculated POT.

By letter dated February 27, 2014 (ADAMS Accession No. ML14063A043), I&M submitted a report describing the impact of an Error in Burst Strain Application on the predicted PCT for CNP Unit 1. This report was submitted pursuant to 10 CFR 50.46(a)(3).

By Westinghouse letter LTR-LIS-14-44, "D. C. Cook Units I and 2 10 CER 50.46 Report for the HOTSPOT Burst Strain Error Correction," dated January 29, 2014, Westinghouse Electric Company notified I&M of significant errors in the EM for the LBLOCA analysis of record for CNP Unit 1.

The following pages summarize the impact of TCD, peaking factor burndown, heat transfer multiplier distribution revisions, error in burst strain application, decay group uncertainty factors errors, changes to grid blockage ratio and porosity, and plant modification evaluations on the CNP Units 1 and 2 LBLOCA analyses of record. In addition, pages are included that summarize the small break LOCA POT analyses of record for CNP Units 1 and 2.

Enclosure to AEP-NRC-201 5-79 Pg Page 3 CNP UNIT 1 LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Evaluation Model: ASTRUM (2004)

FQ = 2.15 FdH = 1.55 SGTP = 10%(a')

Break Size: Split Analysis Date: November 20, 2007 LICENSING BASIS Analysis-of-Record MARGIN ALLOCATIONS (Delta PCT)

A.

PREVIOUS 10 CFR 50.46 ASSESSMENTS

1. Evaluation of TCD and Peaking Factor Burndown

2. Revised Heat Transfer Multiplier Distributions B.

PLANNED PLANT MODIFICATION EVALUATIONS

1. Plant Evaluations associated with TCD

2. PBOT/PMID Evaluation for Cycle 25 C.

NEW 10 CFR 50.46 ASSESSMENTS

1. Error in Burst Strain Application

2. Decay Group Uncertainty Factors Errors D.

OTHER PCT = 2128°F 384°F(a)

-55OF

-381 °F(a) 1 4°F(b) 85° F

-29°F 0OF LICENSING BASIS PCT + MARGIN ALLOCATIONS PCT = 2146°F Notes:

a. These assessments are coupled via an-evaluation of burnup effects which include thermal conductivity degradation, peaking factor burndown and design input changes (e.g., reduction in the maximum allowed steam generator tube plugging from 10% to 2.5% and maximum FdH reduced to 1.545).

b. The 14°F penalty for a PBOT/PMID evaluation is specific to Unit I Cycle 25 which ended on September 24, 2014. The Unit 1 Cycle 26 Licensing basis PCT + margin allocations equals 2132°F.

Enclosure to AEP-NRC-2015-79 Pg Page 4 F

CNP UNIT 1 LOCA Peak Clad Temperature Summary for Appendix K Small Break Evaluation Model:

NOTRUMP FQ=2.32 FdH-1.55 SGTP=10%

3.25 inch cold leg break Analysis Date: January 6, 2012 Notes: 3304 MWt (plus 0.34% calorimetric uncertainty)

LICENSING BASIS Analysis-of-Record PCT = 1 MARGIN ALLOCATIONS (Delta PCT)

A.

PREVIOUS 10 CER 50.46 ASSESSMENTS

1.

None B.

PLANNED PLANT MODIFICATION EVALUATIONS C.

NEW 10 CFR 50.46 ASSESSMENTS D.

OTHER LICENSING BASIS PCT + MARGIN ALLOCATIONS PCT = 1 725°F 0OF 0oF 00OF 0OF 725°F

Enclosure to AEP-NRC-2015-79 Pg Page 5 CNP UNIT 2 LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Evaluation Model: ASTRUM (2004)

FQ = 2.335 FdH = 1.644 SGTP = 10%1(a)

Break Size: Split Analysis Date: February 9, 2009 LICENSING BASIS Analysis-of-Record MARGIN ALLOCATIONS (Delta PCT)

A.

PREVIOUS 10 CFR 50.46 ASSESSMENTS

1. Evaluation of TCD and Peaking Factor Burndown

2. Changes to Grid Blockage Ratio and Porosity

3. Revised Heat Transfer Multiplier Distributions B.

PLANNED PLANT MODIFICATION EVALUATIONS

1. Plant Evaluations associated with TCD C.

NEW 10 CFR 50.46 ASSESSMENTS

1. Error in Burst Strain Application D.

OTHER PCT = 2107°F 73°F(a) 1 6°F

_3OF

-239°F(a) 1 3OF 0OF PCT = 1967°F LICENSING BASIS PCT + MARGIN ALLOCATIONS Notes:

a. These assessments are coupled via an evaluation of burnup effects which include thermal conductivity degradation, peaking factor burndown and design input changes (e.g., reduction in the maximum allowed steam generator tube plugging from 10% to 1%

and maximum FdH reduced to 1.61).

Enclosure to AEP-NRC-201 5-79 Pg Page 6 CNP UNIT 2 LOCA Peak Clad Temperature Summary for Appendix K Small Break Evaluation Model: NOTRUMP FQ = 2.32 FdH = 1.62 SGTP = 10% 4 inch cold leg break Analysis Date: April 25, 2011 Notes: 3600 MWt LICENSING BASIS Analysis-of-Record PCT = 1274°F (a)

MARGIN ALLOCATIONS (Delta PCT)

A.

PREVIOUS 10 CFR 50.46 ASSESSMENTS

1.

None 00F B.

PLANNED PLANT MODIFICATION EVALUATIONS 0°F C.

NEW 10 CFR 50.46 ASSESSMENTS 0°F D.

OTHER 0°F LICENSING BASIS PCT + MARGIN ALLOCATIONS PCT = 12740F Notes:

a. The 3600 MWt power level used in this analysis bounds the Unit 2 3468 MWt steady state power limit in the operating license.