L-2019-058, CFR 50.46 - Emergency Core Cooling System LBLOCA 30-Day Report

CFR 50.46 - Emergency Core Cooling System LBLOCA 30-Day Report

ML19087A118
Person / Time
Site:	Point Beach, Seabrook, Turkey Point
Issue date:	03/25/2019
From:	Parks W Florida Power & Light Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-2019-058
Download: ML19087A118 (8)

Text

L-2019-058 MAR 2 52019

• 10 CFR 50.46 ATIN: Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555 Re: N extEra Energy Point Beach, ILC Point Beach Units 1 and 2, Docket Nos. 50-266, 50-301

/

Florida Power & Light Company Turkey Point Units 3 and 4, Docket Nos. 50-250, 50-251 N extEra Energy Seabrook, LLC Seabrook Station, Docket No. ,50-443 10 CFR 50.46 - Emergency Core Cooling System LBLOCA 30-Day Report Pursuant to 10 CFR 50.46(a)(3)(ii), this letter contains the 30-day report for the Point Beach Nuclear Plant, Units 1 and 2, Turkey Point Nuclear Plant, Units 3 and 4, and* Seabrook Station for the emergency core cooling system analysis performed by Westinghouse Electric Company, LLC, in the respective attachments to this letter.

One error was identified by Westinghouse that affects the Large-Break (LB) LOCA models. The LBLOCA error is related to an error in the vapor temperature resetting logic in the Best-Estimate LOCA evaluation model. The error has a negligible impact on the results of LBLOCA analyses, leading to an estimated peak cladding temperature (PCT) impact of 0°F.

As the reported error is of a 0°F impact, the PCT continues to remain within the limits. However, as the cumulative PCT change already exceeds 50 °F for the LBLOCA analysis, a 30 day 10CFR50.46 report must be issued. Evaluations of each reported error have concluded that re-analysis was not required.

• This letter contains no new or revised regulatory commitments.

Florida Power & Light Company 700 Universe Boulevard, Juno Beach, FL 33408

L-2019-058 Page 2 of2 Should you have any questions regarding this report, please contact Mr. Steve Catron, Fleet Licensing Manager, at (561) 304-6206.

Very truly yours,

/v~71-P--

William Parks Director, Nuclear Licensing and Regulatory Compliance Florida Power & Light Company Attachments (3) cc: USNRC Regional Administrator, Region I USNRC Regional Administrator, Region II USNRC Regional Administrator, Region III USNRC Project Manager, Point Beach Nuclear Plant USNRC Project Manager, Turkey Point Nuclear Plant USNRC Project Manager, Seabrook Station USNRC Senior Resident Inspector, Point Beach Nuclear Plant USNRC Senior Resident Inspector, Turkey Point Nuclear Plant USNRC Senior Resident Inspector, Seabrook Station

ATTACHMENT 1 NextEra Energy Point Beach Units 1 and 2

('

L-2019-058 Attachment 1 Page 1 ofl Point Beach Units 1 and 2 Large Break LOCA PCT 30-Day Report Evaluation Methodology:

Westinghouse, "Realistic Large-Break LOCA Evaluation Methodology Using the Automated Statistical Treatment of Uncertainty Method (ASTRUM)," WCAP-16009-P-A, January 2005.

Westingti.ouse, "Application of Best Estimate Large Break LOGA Methodology to Westinghouse PWRs with Upper Plenum Injection," WCAP-14449-P-A Revision 1, October 1999.

Evaluation Model PCT: 1975°F/1810°F Net PCT Effect Absolute PCT Effect Unit 1/Unit 2 Unit 1/Unit 2 Prior 10 CFR 50.46 Changes or Error Corrections- up to

+210°F/+248°F 210°F/340°F Year 2018( 1)

Prior 10 CFR 50 .46 Changes or Error Gorrections - Year None None 2019 New 10 CFR 50.46 Changes or Error Corrections- Year 2019

/ Error in Vapor Temperature Resetting Logic 0°F/0°F 0°F/0°F Sum of 10 CFR 50.46 Changes or Error Corrections +210°F/+248°F 210°F/340°F The sum of the PCTfrom the most recent analysis using an )

acceptable evaluation model and the estimates ofPCT* 2185°F/2058°F < 2200 °F impact for changes and errors identified since this analysis Error in Vapor Temperature Resetting Logic When the vapor temperature is greater than the wall temperature, and several other conditions are met, the vapor.temperature is reset to the saturation temperature for heat transfer calculations. It is discovered that the vapor temperature resetting logic results in an inconsistency between the conduction solution and the hydraulic solution, such that energy is not conserved between the two solutions. The correction of this error has a negligible impact on the results of LBLOCA analyses.

The PCT.impact of correcting this error is estimated to be 0°F.

Reference:

1. L-2019-057, W. Parks (NextEra Energy) to U.S. Nuclear Regulatory Commission, "10CFR50.46 Annual Reporting of Changes to, or Errors in Emergency Core Cooling System Models or Applications," March 19, 2019.

ATTACHMENT 2 Florida Power & Light Company Turkey Point Units 3 and 4

L-2019-058 Attachment 2 Page 1 of1 Turkey Point Units 3 & 4 Large Break LOCA PCT 30-Day Report Evaluation Methodology:

Westinghouse, "Realistic Large-Break LOCA Evaluation Methodology Using the Automated Statistical Treatment Of Uncertainty Method (ASTRUM)," WCAP-16009-P-A, Revision 0, January 2005 Evaluation Model PCT: 2152 °F (Reference 1)

Net PCT . Absolute PCT Effect Effect Prior 10 CPR 50.46 Changes or Error Corrections - up to

-28 °P 80 °P year 2018 (Reference 2)

Prior 10 CPR 50.46 Changes or Errors Corrections-year None 2019 New 10 CPR 50.46 Changes or Errors Corrections-year 2019 I Error in Vapor Temperature Resetting Logic 0 op 0 op Sum of 10 CPR 50.46 Changes or Errors Corrections -28 °P 80 °P The sum of the PCT from the most recent analysis using an acceptable evaluation model and the estimates of PCT impact 2124 °F < 2200 °F for changes and errors identified since this analysis Error in Vapor Temperature Resetting Logic When the vapor temperature is greater than the wall temperature, and several other conditions are met, the vapor temperature is reset to the saturation temperature for heat transfer calculations. It is discovered that the vapor temperature resetting logic results in an inconsistency between tqe conduction solution and the hydraulic solution, such that energy is not conserved between the two solutions. The correction of this .

error has a negligible impact on the results of LBLOCA analyses.

The PCT impact of correcting this error is estimated to be 0°P.

References:

1. L-2012-019, M. Kiley (NextEra Energy) to U.S. Nuclear Regulatory Commission, "Response to NRC Reactor Systems Branch Request for Additional Information Regarding Extended Power Uprate License Amendment Request No. 205 and Thermal Conductivity Degradation," January 16, 2012.

1. L-2019-057, W. Parks (NextEra Energy) to U.S. Nuclear Regulatory Commission, "I0CPR50.46 Annual Reporting of Changes to, or Errors in Emergency Core Cooling System Models or Applications," March 19, 2019.

ATTACHMENT 3 N extEra Energy Seabrook Station

L-2019-058 Attachment 3 Page 1 of1 Seabrook Unit 1 Large Break LOCA PCT 30-Day Report Evaluation Methodology:

Westinghouse, "Code Qualification Document for Best Estimate LOCA Analysis," WCAP-12945-P-A, March 1998 Evaluation Model PCT: 1784 °F (Reference 1)

Net PCT Absolute PCT Effect Effect Prior 10 CPR 50.46 Changes or Error Corrections - up to 155 °P 155 °P year 2018 (Reference 2)

Prior 10 CPR 50 .46 Changes or Errors Corrections - year None 2019 New 10 CPR 50.46 Changes or Errors Corrections-year 2019 J Error in Vapor Temperature Resetting Logic 0 op 0 op Sum of 10 CPR 50.46 Changes or Errors Corrections 155 °P 155 °P The sum of the PCTfrom the most recent analysis using an acceptable evaluation model and the estimates ofPCT impact 1939 °F < 2200 °F for changes and errors identified since this a,nalysis Error in Vapor Temperature Resetting Logic When the vapor temperature is greater than the wall temperature, and several other conditions are met, the vapor temperature is reset to the saturation temperature for heat transfer calculations. It is discovered that the vapor temperature resetting logic results in an inconsistency between the conduction solution and the hydraulic solution, such that energy is not conserved between the two solutions. The correction of this error has a negligible impact on the results ofLBLOCA analyses.

The PCT impact of correcting this error is estimated to be 0°P.

References:

1. NYN-04016, M. Warner (NextEra Energy) to U.S. Nuclear Regulatory Commission, "License Amendment Request 04-03, Application for Stretch Power Uprate," March 17, 2004.

2. L-2019-057, W. Parks (NextEra Energy) to U.S. Nuclear Regulatory Commission, "10CPR50.46 Annual Reporting of Changes to, or Errors in Emergency Core Cooling System Models or Applications," March 19, 2019.