L-2017-157, Acceptance Criteria for Emergency Core Cooling Systems for Light Water Nuclear Power Reactors, 10 CFR 50.46 30-Day Report

Acceptance Criteria for Emergency Core Cooling Systems for Light Water Nuclear Power Reactors, 10 CFR 50.46 30-Day Report

ML17258A037
Person / Time
Site:	Saint Lucie
Issue date:	09/13/2017
From:	Larry Nicholson Florida Power & Light Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-2017-157
Download: ML17258A037 (3)

Text

L-2017-157 SEP 1 32017 10 CFR 50.46 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 Re: St. Lucie Unit 1 Docket No. 50-335 Acceptance Criteria for Emergency Core Cooling Systems for Light Water Nuclear Power Reactors 10 CFR 50.46 30-Day Report Florida Power & Light (FPL) was informed of changes to the AREVA small break loss of coolant accident (LOCA) analyses M5 cladding swelling and rupture model (SRM) due to additional available test data following the model's approval by the NRG as part of M5 licensing. Following the same approach as the original model, an updated M5 SRM was developed to take into account the updated test database. This caused a change in post rupture cladding characteristics for certain rupture temperatures. The estimated impact for St. Lucie Unit 1 is 0°F and the peak cladding temperature (PCT) value continues to remain within the regulatory limit of 2200 °F provided in 10 CFR 50.46.

However, the accumulated effect on PCT is greater than 50 °F.

According to 10 CFR 50.46, when a cumulative PCT change due to errors or changes to the analysis of 50 °F occurs, a 30 day report shall be sent to the NRG with a proposed schedule for providing reanalysis or taking action as may be needed to show compliance with 50.46 requirements. This information is provided in the attachment to this letter.

Please contact Larry Nicholson at (561) 304-6224 should you have any questions regarding this submittal.

S;?e~

Larry Nicholson Director, Nuclear Licensing and Regulatory Compliance Enclosure (1)

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

St. Lucie Unit 1 L-2017-157 Docket No. 50-335 Enclosure 10 CFR 50.46 Change Report Page 1 of 2 St. Lucie Unit 1 10 CFR 50.46 30-Day Report Emergency core cooling system (ECCS) small break loss of coolant accident (SBLOCA) analysis for St. Lucie Unit 1 is performed by AREVA Inc. The following 30-Day report, pertaining to the application of the AREVA SBLOCA evaluation model, is provided pursuant to 10 CFR 50.46(a)(3)(ii). A summary of the model changes/errors and the estimated impact on the peak cladding temperature (PCT) for SBLOCA is provided in Table 1.

1.0 SBLOCA Model Changes o M5 LOCA Swelling and Rupture Model (SRM) Update AREVA determined that certain aspects of the SRM model would be impacted when considering additional M5 cladding rupture test data since the model's approval by the NRC as part of M5 licensing. Following the same approach as the original model, an updated M5 SRM was developed to take into account the updated test database. This caused a change in post rupture cladding characteristics for certain rupture temperatures. The rupture temperatures in the St. Lucie Unit 1 SBLOCA analysis are less than the range of model changes and therefore there is no change to the PCT.

• The issue was evaluated and the PCT impact is estimated to be 0 °F for St. Lucie Unit 1.

Previous SBLOCA PCT changes are documented in Reference 2.1. Table 1 summarizes the estimated impact of the changes/errors on the St. Lucie Unit 1 SBLOCA PCT, along with the cumulative effect of absolute PCT changes.

The limiting SBLOCA PCT with the estimated effects of all the changes/errors is 1850 °F, which is unchanged from that reported in Reference 2.1, and maintains significant margin to the limit of 2200°F. St. Lucie Unit 1 thus continues to remain in compliance with the 10 CFR 50.46 requirements.

2.0 References 2.1 L-2017-056, "St. Lucie Units 1 and 2 Docket Nos. 50-335 and 50-389 Acceptance Criteria for Emergency Core Cooling Systems for Light Water Nuclear Power Reactors 10 CFR 50.46 Annual Report," March 27, 2017. (ML17086A321).

.-' St. Lucie Unit 1 L-2017-157 Docket No. 50-335 Enclosure 10 CFR 50.46 Change Report Page 2 of 2 Enclosure 1 St. Lucie Unit 1 SBLOCA Margin Summary Sheet - 30 Day Report Plant Name: St. Lucie Unit 1 Utility Name: NextEra Energy Evaluation Model: EMF-2328(P)(A) Rev. O as supplemented by ANP-3000(P), Revision 0.

Evaluation Model PCT: 1828°F Net PCT Absolute PCT Effect Effect Prior 10 CPR 50.46 Changes or Error Corrections-A +22 °P 82 °P up to Year 2016 Prior 10 CPR 50.46 Changes or Error Corrections-B None None Year 2017 c 10 CPR 50.46 Changes in Year 2017 Since Item B SRM Model Update due to new rupture test data 0 op 0 op D Sum of 10 CPR 50.46 Changes +22 °P 82 °P The sum of the PCTfrom the most recent analysis using an acceptable evaluation model and the estimates ofPCT 1850 °F < 2200 °F impact for changes and errors identified since this analysis