NRC 2006-0047, ECCS Evaluation Model Changes, 10 CFR 50.46

ECCS Evaluation Model Changes, 10 CFR 50.46

ML061290051
Person / Time
Site:	Point Beach
Issue date:	05/05/2006
From:	Koehl D Nuclear Management Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NRC 2006-0047
Download: ML061290051 (3)

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Commirted a,Nuclear Excellence -OP P m Operated by Nuclear Management Company, LLC May 5,2006 NRC 2006-0047 10 CFR 50.46 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington DC 20555 Point Beach Nuclear Plant, Units Iand 2 Dockets 50-266 and 50-301 License Nos. DPR-24 and DPR-27 ECCS Evaluation Model Chanaes. 10 CFR 50.46 As required by 10 CFR 50.46(a)(3)(ii), Nuclear Management Company, LLC (NMC), is submitting this annual report of changes to, and emrs discovered in, emergency core cooling system (ECCS) evaluation models for Point Beach Nuclear Plant (PBNP)

Units Iand 2. This letter is intended to provide a summary of ECCS evaluation model changes and errors identified since our previous annual report dated April 25,2005 (NRC-2005-0053). Model changes include changes to the large break loss of coolant accident (LOCA) model and the small break LOCA model. Changes are summarized below with additional details and a summary sheet of peak cladding temperature (PCT) margin provided in the enclosure.

For PBNP Units 1 and 2, there were no changes in 2005 to the PCT assessment for the large break LOCA or small break LOCA analyses. Current PCT rack-up sheets are provided in the enclosure to this letter.

There are no new commitmentsflcontained in this submittal.

Dennis L. Koehl Site Vice-President, Point Nuclear Management

Enclosure:

ECCS Evaluation Model Changes and Errors Regional Administrator, Region Ill, USNRC Project Manager, Point Beach Nuclear Plant, USNRC Resident Inspector, Point Beach Nudear Plant, USNRC PSCW 6590 Nuclear Road 'liNa Rlvem, Wisconsin 54241 Telephone: 920.755.2321

ENCLOSURE ECCS EVALUATION MODEL CHANGES AND ERRORS POINT BEACH NUCLEAR PLANT, UNITS 1AND 2 Larae Break LOCA Evaluation Model There were no changes or errors to the Large Break LOCA evaluation model during this reporting period that resulted in a change to the calculated PCT for Point Beach Nuclear Plant.

Small Break LOCA Evaluation Model There were no changes or errors to the Small Break LOCA evaluation model during this reporting period that resulted in a change to the calculated PCT for Point Beach Nuclear Plant.

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LARGE BREAK PEAK CLADDING TEMPERATURE MARGIN UTlLlZATlON FOR BELOCA PBNP Units 1 & 2:

A. Analysis of Record (11/2000) PCT =

B. Prior Permanent ECCS Model Assessments

1. MONTECF Decay Heat Uncertainty Factor APCT =

2. Revised Blowdown Heatup Uncertainty Distribution APCT =

C. Planned Plant Change Evaluations

1. Measurement Uncertainty Recapture Power Uprate APCT =

D. 2005 10 CFR 50.46 Model Assessments APCT =

E. Temporary ECCS Model Issues (none) APCT =

F. Other Margin Allocations (none) APCT =

Licensing Basis PCT + Margin Allocations PCT =

SMALL BREAK PEAK CLADDING TEMPERATURE MARGIN UTILIZATION jThree Inch Cold L e a PBNP Units 1 & 2:

A. Analysis of Record (1112000)" PCT = 1157°F 1 1046°F

6. Prior Permanent ECCS Model Assessments

1. NOTRUMP Mixture Level TrackingIRegion Depletion APCT = 13°F

2. NOTRUMP Bubble RiseiDrift Flux Model Inconsistency APCT = 35°F C. 10 CFR 50.59 Safety Evaluations (none) APCT = O°F D. 2005 10 CFR 50.46 Model Assessments (none) APCT = 0°F E. Temporary ECCS Model Issues (none) APCT = 0°F F. Other Margin Allocations (none) APCT = 0°F Licensing Basis PCT + Margin Allocations PCT = 120S°F I1094°F

" Unit I/Unit 2 Page 2 of 2