NL-13-2277, 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2012 and Significant Change/Error Report

10 CFR 50.46 ECCS Evaluation Model Annual Report for 2012 and Significant Change/Error Report

ML13304A539
Person / Time
Site:	Farley
Issue date:	10/30/2013
From:	Pierce C Southern Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NL-13-2277
Download: ML13304A539 (8)

Text

Charles R. Pierce Southern Nuclear Regulatory Affa irs Director Operating Company, Inc.

40 Inve rn ess Center Parkway Post Office Box 1295 Bi rmingham. Alabama 35201 Tel 205.992.7872 Fax 205992.7601 October 30, 2013 SOUTHERN ' \

COMPANY Docket Nos.: 50-348 NL-13-2277 50-364 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Joseph M. Farley Nuclear Plant 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2012 and Significant Change/Error Report Ladies and Gentlemen:

In accordance with the requirements of 10 CFR 50.46(a)(3)(ii) , Southern Nuclear Operating Company (SNC) is submitting the enclosed Joseph M. Farley Nuclear Plant Units 1 & 2 (FNP) emergency core cooling system (ECCS) evaluation model significant change/error report.

On October 4, 2013, SNC received notification from its fuel vendor, Westinghouse Electric Company LLC (Westinghouse), of a change/error report which included the estimated effect on the FNP limiting ECCS analysis fuel peak cladding temperature (PCT). Westinghouse performed an evaluation of the FNP best estimate large break loss-of-coolant accident (BE LBLOCA) analysis of record (AOR), and concluded that the estimated PCT impact is +24°F for 10 CFR 50.46 reporting purposes.

Prior to this notification, on July 31,2013, SNC received notification from Westinghouse of a separate change/error report which included the estimated effect on the FNP limiting ECCS analysis PCT. Westinghouse performed an evaluation of the FNP BE LBLOCA AOR, and concluded that the estimated PCT impact is -40°F for 10 CFR 50.46 reporting purposes.

The combined notifications constitute a significant change/error requiring a 30 day report, which is provided in the Enclosure. The requirements of 10 CFR 50.46(a)(3)(ii) also include an annual report by licensees of changes to, or errors in, acceptable ECCS models that affect the temperature calculation and the estimated effect of changes or errors on the limiting ECCS analysis. Accordingly, the Enclosure also includes a summary of changes/errors for 2012 for both the FNP LBLOCA and the FNP small-break loss-of-coolant accident (SBLOCA).

This letter contains no NRC commitments. If you have any questions , please contact Ken McElroy at (205) 992-7369.

U. S. Nuclear Regulatory Commission NL-13-2277 Page 2 Sincerely, C. f( 6J~

C.R. Pierce Regulatory Affairs Director CRP/RM"I/Iac

Enclosure:

Farley Nuclear Plant 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2012 & Significant Change/Error Report cc: Southern Nuclear Operating Company Mr. S. E. Kuczynski, Chairman, President & CEO Mr. D. G. Bost, Executive Vice President & Chief Nuclear Officer Mr. T. A. Lynch, Vice President - Farley Mr. B. L. Ivey, Vice President - Regulatory Affairs Mr. B. J. Adams, Vice President - Fleet Operations RTYPE: CFA04.054 U. S. Nuclear Regulatory Commission Mr. V. M. McCree, Regional Administrator Ms. M. Barillas, NRR Project Manager - Farley Mr. P. K. Niebaum, Senior Resident - Farley Mr. J. R. Sowa, Senior Resident - Farley Mr. R. E. Martin, Senior Project Manager- Farley

Joseph M. Farley Nuclear Plant 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2012 & Significant Change/Error Report Enclosure Farley Nuclear Plant 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2012 & Significant Change/Error Report

Enclosure to NL-13-2277 Farley Nuclear Plant 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2012 & Significant Change/Error Report Joseph M. Farley Nuclear Plant - Unit 1 ASTRUM Best Estimate Large Break LOCA Evaluation Table 1-1a - Current Changes/Errors Estimated Description Effect (Ll PCT OF)

A change in the methodology used to calculate grid blockage ratio and porosity for Westinghouse fuel resulted in a change to the grid inputs used in the Joseph M.

+24 Farley (FNP) Units 1 and 2 large break loss-of-coolant accident (LBLOCA) analysis.

Grid inputs affect heat transfer in the core during a LBLOCA.

Several changes and error corrections were made to COBRAfTRAC and the impacts of these changes on the heat transfer multiplier uncertainty distributions were investigated. During this investigation, errors were discovered in the development of the original multiplier distributions, including errors in the grid locations specified in the WCOBRAfTRAC models for the G2 Refill and G2 Reflood tests, and errors in processing test data used to develop the reflood heat transfer multiplier distribution. Therefore, the blowdown heatup, blowdown cooling, refill, and reflood heat transfer multiplier distributions were redeveloped. For the reflood -40 heat transfer multiplier development, the evaluation time windows for each set of test experimental data and each test simulation were separately defined based on the time at which the test or simulation exhibited dispersed flow film boiling heat transfer conditions characteristic of the reflood time period. The revised heat transfer multiplier distributions have been evaluated for impact on existing analyses. Resolution of these issues represents a closely related group of Non-Discretionary Changes in accordance with Section 4.1.2 of WCAP-13451.

Table 1-1b - Summary of Changes/Errors (2012)

Estimated Description Effect tLl PCT °Fl None affecting PCT* N/A Table 1-1c - Cumulative Impact of Changes/Errors LlIPCTI Description (OF)

• Changes/Errors Previously Reported (Reference 1) 0*

• Summary of Changes/Errors (2012) (Reference 2) 0*

• Current Changes/Errors (Reference 3, 4) 64 Cumulative Total 64

• On October 18, 2012, a SIgnIfIcant Change/Error Report for FNP was submItted (Reference 1). ThIS "reset" the baseline PCT for reporting purposes. There were no additional changes/errors in 2012 from those reported in Reference 1.

E-1

Enclosure to NL-13-2277 Farley Nuclear Plant 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2012 & Significant Change/Error Report Joseph M. Farley Nuclear Plant - Unit 1 NOTRlIMP Appendix K Small Break LOCA Evaluation Table 1-1d - Summary of Changes/Errors (2012)

Estimated Description Effect (ll PCT OF)

None affecting PCT N/A Table 1-1e - Cumulative Impact of Changes/Errors ll\PCT\

Description (OF)

• Changes/Errors Previously Reported (Reference 1) 0*

• Summary of Changes/Errors (2012) (Reference 2) 0*

Cumulative Total 0 E-2

Enclosure to NL-13-2277 Farley Nuclear Plant 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2012 & Significant Change/Error Report Joseph M. Farley Nuclear Plant - Unit 2 ASTRUM Best Estimate Large Break LOCA Evaluation Table 1-2a - Current Changes/Errors Estimated Description Effect

(~PCT OF)

A change in the methodology used to calculate grid blockage ratio and porosity for Westinghouse fuel resulted in a change to the grid inputs used in the Joseph M.

+24 Farley (FNP) Units 1 and 2 large break loss-of-coolant accident (LBLOCA) analysis.

Grid inputs affect heat transfer in the core during a LBLOCA.

Several changes and error corrections were made to COBRAfTRAC and the impacts of these changes on the heat transfer multiplier uncertainty distributions were investigated. During this investigation, errors were discovered in the development of the original multiplier distributions, including errors in the grid locations specified in the WCOBRAfTRAC models for the G2 Refill and G2 Reflood tests, and errors in processing test data used to develop the reflood heat transfer multiplier distribution. Therefore, the blowdown heatup, blowdown cooling, refill, and reflood heat transfer multiplier distributions were redeveloped. For the reflood -40 heat transfer multiplier development, the evaluation time windows for each set of test experimental data and each test simulation were separately defined based on the time at which the test or simulation exhibited dispersed flow film boiling heat transfer conditions characteristic of the reflood time period. The revised heat transfer multiplier distributions have been evaluated for impact on eXisting analyses. Resolution of these issues represents a closely related group of Non-Discretionary Changes in accordance with Section 4.1.2 of W CAP-13451 .

Table 1-2b - Summary of Changes/Errors (2012)

Estimated Description Effect

(~PCT OF)

None affecting pcr N/A Table 1-2c - Cumulative Impact of Changes/Errors

~IPCTI Description (OF)

• Changes/Errors Previously Reported (Reference 1) 0*

• Summary of Changes/Errors (2012) (Reference 2) 0*

• Current Changes/Errors (Reference 3, 4) 64 I

Cumulative Total 64

• On October 18, 2012, a Significant Change/Error Report for FNP was submitted (Reference 1). This "reset" the baseline PCT for reporting purposes. There were no additional changes/errors in 2012 from those reported in Reference 1.

E-3

Enclosure to NL-13-2277 Farley Nuclear Plant 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2012 & Significant Change/Error Report Joseph M. Farley Nuclear Plant - Unit 2 NOTRUMP Appendix K Small Break LOCA Evaluation Table 1-2d - Summary of Changes/Errors (2012)

Estimated Description Effect

(,1 PCT OF)

None affecting PCT N/A Table 1-2e - Cumulative Impact of Changes/Errors

,1IPCTI Description (OF)

• Changes/Errors Previously Reported (Reference 1) 0*

• Summary of Changes/Errors (2012) (Reference 2) 0*

Cumulative Total 0 E-4

Enclosure to NL-13-2277 Farley Nuclear Plant 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2012 & Significant Change/Error Report

References:

1. Letter from Mark J. Ajluni to USNRC (NL-12-1983), "Joseph M. Farley Nuclear Plant 10 CFR 50.46 ECCS Evaluation Model Annual Report for 2012 and Significant Change/Error Report," dated October 18, 2012

2. Westinghouse Letter LTR-LlS-13-80, "J. M. Farley Units 1 and 2, 10 CFR 50.46 Annual Notification and Reporting for 2012, II dated February 28, 2013

3. Westinghouse Notification Letter LTR-LlS-13-474, "J. M. Farley Units 1 and 2 10 CFR 50.46 Report for Changes to Grid Blockage Ratio and Porosity," dated October 4, 2013

4. Westinghouse Notification Letter LTR-US-13-361, "J. M. Farley Units 1 and 2 10 CFR 50.46 Report for Revised Heat Transfer Multiplier Distributions," dated July 31, 2013 E-5