NRC 2014-0086, 10 CFR 50.46 30-Day Report

10 CFR 50.46 30-Day Report

ML14345A978
Person / Time
Site:	Point Beach
Issue date:	12/11/2014
From:	Millen M Point Beach
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NRC 2014-0086
Download: ML14345A978 (3)

Text

EXTera ENERGY ~

POINT BEACH December 11, 2014 NRC 2014-0086 10 CFR 50.46(a)(3)(ii)

U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Point Beach Nuclear Plant, Units 1 and 2 Dockets 50-266 and 50-301 Renewed License Nos. DPR-24 and DPR-27 10 CFR 50.46 30-Day Report In accordance with 10 CFR 50.46(a)(3)(ii), NextEra Energy Point Beach, LLC (NextEra) is submitting this 30-day report for the Point Beach Nuclear Plant (PBNP) Units 1 and 2 for the emergency core cooling system (ECCS) analysis performed by Westinghouse Electric Company, LLC. The report pertains to the evaluation of error in the decay group uncertainty factors in PBNP Units 1 and 2 best-estimate (BE) large-break loss-of-coolant accident (LBLOCA) analyses.

The Enclosure describes the ECCS evaluation model error for the LBLOCA. Table 1 provides the LBLOCA margin summary sheet.

This submittal contains no new commitments or revisions to existing commitments.

Very truly yours, NextEra Energy Point Beach, LLC Michael Millen Licensing Manager Point Beach Nuclear Plant Enclosure cc: Administrator, Region Ill, USNRC Project Manager, Point Beach Nuclear Plant, USNRC Resident Inspector, Point Beach Nuclear Plant, USNRC NextEra Energy Point Beach, LLC, 6610 Nuclear Road, Two Rivers, WI 54241

ENCLOSURE NEXTERA ENERGY POINT BEACH, LLC POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 10 CFR 50.46 30-DAY REPORT Emergency core cooling system (ECCS) analyses for Point Beach Units 1 and 2 are performed by Westinghouse Electric Company, LLC. Previous LBLOCA PCT changes with ~ 50°F cumulative peak cladding temperature (PCT) changes were reported via Reference 3.1. The following 30-Day report pertaining to the application of the Westinghouse Large-Break Loss-of-Coolant Accident (LBLOCA) evaluation model is provided pursuant to 10 CFR 50.46(a)(3)(ii). A summary of the PCT changes for LBLOCA is provided in Table 1.

1.0 Changes to LBLOCA Analysis Error in Decay Group Uncertainty Factors The decay group uncertainty factors were not correctly applied to 238 U and 239 Pu and the decay group uncertainty factor for 235 U was erroneously coded as 2.5% instead of 2.25%.

Correction of the error impacts the application of the sampled decay heat uncertainty, which may result in small changes to the decay heat power.

• The estimated impact of the error is 0 °F for Unit 1 and +2 °F for Unit 2.

Previous LBLOCA PCT changes are documented in Reference 3.1. Table 1 summarizes the estimated impact of the changes/errors on the Point Beach Units 1 and 2 LBLOCA PCT, along with the cumulative effect of absolute PCT changes for both Point Beach Units. The limiting LBLOCA PCT with the estimated effect of all the changes/errors is 2185 oF for Unit 1 and 2058 oF for Unit 2.

With the impact of all changes/errors, Point Beach Units 1 and Unit 2 continue to comply with the 10 CFR 50.46 acceptance criterion for PCT of ~2200 °F.

2.0 Proposed Schedule The schedule for LBLOCA re-analyses is as provided previously in Reference 3.2.

3.0 References 3.1 NextEra Energy Point Beach, LLC letter to NRC, dated April 18, 2014, "Point Beach Nuclear Plant, Units 1 and 2, Dockets 50-266 and 50-301, Renewed License Nos. DPR-24 and DPR-27, 10 CFR 50.46 Annual Report/30-Day report" (ML14106A535).

3.2 NextEra Energy Point Beach, LLC letter to NRC, dated March 1, 2013, "Thermal Conductivity Degradation Impact on Large Break Loss of Coolant Accident Analyses with ASTRUM Response to Request for Additional Information" (ML13063A289).

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Table 1 Large Break LOCA Margin Summary Sheet- 30-Day Report Plant Name: Point Beach Units 1 and 2 Utility name: NextEra Energy Evaluation Model: Westinghouse Realistic Large Break LOCA Evaluation Model using ASTRUM (WCAP-16009-P-A)

Evaluation Model PCT (Unit 1/Unit 2):

Absolute PCT Net PCT Effect Effect Unit 11Unit 2 Unit 1/Unit 2 Prior 10 CFR 50.46 Changes or A L'iPCT +160 °F I +246 °F 160 °F I 338 °F Errors Corrections- up to Year 2013 Prior 10 CFR 50.46 Changes or 50 OF I 0 OF B L'lPCT +50 OF I 0 OF Errors Correction- Year 2014 10 CFR 50.46 Changes in Year 2014 c Since Item B Error in Decay Group Uncertainty 0 OF I +2 OF 0 OF I 2 OF L'iPCT Factors L'iPCT 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 2185 °F/2058 °F < 2200 °F analysis Page 2 of 2