ML20217B747

Provides Notification of Change in PCT of More than 50 F,Per Requirements of 10CFR50.46(a)(3)(i),(ii).Tabulation of Large Break LOCA PCT Margin Utilization Applicable to Seabrook Station,Encl

ML20217B747
Person / Time
Site:	Seabrook
Issue date:	10/01/1999
From:	Feigenbaum T NORTH ATLANTIC ENERGY SERVICE CORP. (NAESCO)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
AR#99013980, NYN-99091, NUDOCS 9910130052
Download: ML20217B747 (3)

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The Northeast Utilitin Syntem October 1,1999 Docket No. 50-443 NYN-99091 AR#99013980

. United States Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Seabrook Station North Atlantic Reporting of Changes to, or Errors In

- Emergency Core Cooling System Models or Applications Pursuant to the requirements of 10CFR 50.46(a)(3)(i), (ii), North Atlantic Energy Service Corporation (North Atlantic) provides notification of a change in peak cladding temperature (PCT) of more than 50 F. A change in the Westinghouse BART/ BASH Evaluation Model assessment, (revised 9/21/99), resulted in an increase of 15 F for LOCABART spacer grid single-phase heat transfer error and an increase of 43. F for LOCABART zirc-water oxidation error. The increase for the Large Break LOCA PCT is 58 F resulting in a total PCT of 2050 F.

There are no changes to the Small Break LOCA PCT value.

Enclosed is a tabulation of the Large Break LOCA PCT margin utilization applicable to Seabrook Station.

Should you have any questions regarding this report, please contact Mr. James M. Peschel,

. Regulatory Compliance Manager at (603) 773-7194.

Very truly yours, NORTH ATLANTIC ENERGY SERVICE CORP.

WW fed C. Feigenbaum Mr m 1gm10 Executive Vice Pre ent and i Chief Nuclear Officer cc: IL J. Miller, NRC Region I Administrator J. T. Harrison, NRC Project Manager, Project Directo) ate 1-2 g R. K. Lorson, NRC Senior Resident Inspector j g 9910130052 991001 PDR ADOCK 05000443.

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Large Break Peak Clad Temperature Margin Utilization ECCS EVALUATION MODEL REVISIONS / ERRORS 10 CFR 50.46 REPORT

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Evaluation Model : basil Fuel: 17x17 V511 FQ=2.5 l

F A 11=1.65 SGTP=13% 3411MWt Lice Break Size: Cd = 0.6 Clad Temperature A. ANALYSIS OF RECORD (8/93)

1. ECCS Analysis PCT = 1889 F

2. Increased T-AVG Uncertainty for RTD Bypass Elimination APCT= 5F i

B. PRIOR PERMANENT ECCS MODEL ASSESSMENTS APCT= 73 F ,

1 C. 10 CFR 50.46 Model Assessment (Permanent Assessments of PCT Margin)

1. LOCABART Spacer Grid Single-Phase fleat Transfer j Er.or APCT= 15 F l l I l 2. LOCABART Zirc-Water Oxidation Error APCT= 43 F l l i D. OTIIER MARGIN ALLOCATIONS

1. +/- 5 F T-AVG Window APCT= 25 F i

LICEN51NG BASIS PCT + MARGIN ALLOCATIONS PCT = 2050 F Page1ofI