L-2024-064, Florida Power & Light Company - 10 CFR 50.46 - Emergency Core Cooling System SBLOCA 30-Day Report

Florida Power & Light Company - 10 CFR 50.46 - Emergency Core Cooling System SBLOCA 30-Day Report

ML24109A010
Person / Time
Site:	Saint Lucie
Issue date:	04/17/2024
From:	Rasmus P Florida Power & Light Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
L-2024-064
Download: ML24109A010 (1)

Text

U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Re:

Florida Power & Light Company April 17, 2024 St. Lucie Unit 2, Docket No. 50-389 10 CFR 50.46 - Emergency Core Cooling System SBLOCA 30-Day Report L-2024-064 10 CFR 50.46 Pursuant to 10 CFR 50.46(a)(3)(ii), this letter contains the 30-day report for the Florida Power &

Light's St. Lucie Nuclear Plant, Unit 2, for the emergency core cooling system analysis performed by Framatome, described in the attachment to this letter.

A legacy error was identified in analytical inputs for the RCP homologous curves that impacts both the Realistic Large-Break (RLB) and the Small-Break (SB) LOCA analyses.

As the reported error is of a 0°F impact, the peak cladding temperature (PCT) continues to remain within the limits. However, as the cumulative PCT change already exceeds 50 °F for the SBLOCA analysis, a 30-day 1 OCFR50.46 report must be issued. The cumulative change for the RLBLOCA remains under 50 °F and therefore no report for RLBLOCA is attached. An evaluation of the reported error has concluded that re-analysis is not required.

This letter contains no new or revised regulatory commitments.

Should you have any questions regarding this report, please contact Mr. Kenneth Mack, Fleet Licensing Manager, at (561) 904-3635.

Very truly yours,

~177 ~

~asmus General Manager, Regulatory Affairs Florida Power & Light Company Attachment ( 1) cc:

USNRC Regional Administrator, Region II USNRC Project Manager, St. Lucie Nuclear Plant USNRC Senior Resident Inspector, St. Lucie Nuclear Plant Florida Power & Light Company 6501 S. Ocean Drive, Jensen Beach, FL 34957

St. Lucie Unit 2 Small Break LOCA PCT 30-Day Report Evaluation Methodology:

L-2024-064 10 CFR 50.46 Page 1 of 1 Framatome, "PWR Small Break LOCA Evaluation Model, S-RELAP5 Based," EMF-2328(P)(A)

Revision.O.

Evaluation Model PCT:

2057 °F (Reference 1)

Prior 10 CFR 50.46 Changes or Error Corrections - up to Year 2023 (Reference 1)

Prior 10 CFR 50.46 Changes or Error Corrections -

Year2024 New 10 CFR 50.46 Changes or Error Corrections -

Year2024 J Legacy error in homologous pump curve Sum of 10 CFR 50.46 Changes or Error Corrections The sum of the PCT from the most recent analysis using an acceptable evaluation model and the estimates of PCT impact for changes and errors identified since this analysis Net PCT Effect Absolute PCT Effect

-279°F 393 °F None None 0°F 0°F

-279°F 393 °F 1778 °F < 2200 °F Legacy error in Reactor Coolant Pump (RCP) homologous curves.

A legacy error was identified in analytical inputs for the RCP homologous curves. The erroneous input error was evaluated by Framatome. The error has a negligible impact on the results of SBLOCA analysis, leading to an estimated peak cladding temperature (PCT) impact of O 0 F.

Reference:

1. Letter from S. Catron to U.S. Nuclear Regulatory Commission, "10 CFR 50.46 Annual Reporting of Changes to, or Errors in Emergency Core Cooling System Models or Applications," L-2024-011, March 13, 2024 [ML24073A190].