ML17348A948

Forwards Rept Re 10CFR50.46, Acceptance Criteria for ECCS in Light Water Nuclear Power Reactors & Actions Required to Show Compliance W/Requirements

ML17348A948
Person / Time
Site:	Turkey Point
Issue date:	06/07/1991
From:	Plunkett T FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9106190258
Download: ML17348A948 (9)

Text

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REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9106190258 DOC.DATE: 91/06/07 NOTARIZED: NO DOCKET FACIL:50-250 Turkey Point Plant, Unit 3, Florida Power and Light C 05000250 50-251 Turkey Point Plant, Unit 4, Florida Power and Light C 05000251 AUTH. NAME AUTHOR AFFILIATION PLUNKETT,T.F. Florida Power S Light Co.

RECIP.NAME RECIPIENT AFFILIATION R Document Control Branch (Document Control Desk)

SUBJECT:

Forwards rept re 10CFR50.46, "Acceptance Criteria for ECCS in Light Water Nuclear Power Reactors" S actions required to D show compliance w/requirements.

DISTRIBUTION CODE: A001D COPIES RECEIVED:LTR ENCL SIZE:

TITLE: OR Submittal: General Distribution NOTES:

A RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL D PD2-2 LA 1 1 PD2-2 PD 1 1 AULUCK,R 2 2 D INTERNAL: NRR/DET/ECMB 7D 1 1 NRR/DET/ESGB 1 1 NRR/DOEA/OTS B1 1 1 1 NRR/DST 8E2 1 1 NRR/DST/SELB 7E 1 1 NRR/DST/SICB8H7 1 1 NRR/DST/SRXB 8E 1 1 NUDOCS-ABSTRACT 1 1 e~FMH 1 0 OGC/HDS3 1 0 REG LE Ol 1 1 RES/DSIR/EIB 1 1 EXTERNAL: NRC PDR 1 1 NSIC 1 1 D

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P.. Box 029100, Nliami, FL, 33102-9100 L-91-165 10 CFR 50.46 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 Gentlemen:

Re: Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 10 CFR 50.46, "Acceptance Criteria for Emergency Core Cooling Systems In Light Water Nuclear Power Reactors" Evaluation Model Regnal sis 10 CFR 50.46 (a)(3)(ii) requires that licensees report to the Commission each change to an acceptable emergency core cooling system (ECCS) evaluation model, or in the application of such model, that affects the peak clad temperature calculation, and their effect on the limiting ECCS analysis. If the change results in a peak clad temperature difference of more then 50'F, the licensee is required to provide the NRC with a report within 30 days and include with the report the actions required to show compliance with 10 CFR 50.46 requirements.

On May 10, 1991, Westinghouse transmitted the results of the reanalysis of the worst case large and small break LOCA transients. Since these results exceed the 50'F peak clad temperature difference, FPL is required to provide the enclosed response within 30 days of receipt of Westinghouse's results.

Should there be any questions, please contact us.

Very truly yours, T. F. Plunkett Vice President Turkey Point Nuclear Attachment TFP/RJT/r j t cc: Stewart D. Ebneter, Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, Turkey Point Plant 91.0619025e 9>06007250 y0 PDR ADOCK 05000250 p I

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L-91-165 Page 1 of 4 ATTACHMENT Re: Turkey Point Units 3 and 4 Docket Nos 50-250 and 50-251

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10 CFR 50.46, "Acceptance Criteria for Emergency Core Cooling Systems in Light Water Nuclear Power Reactors" Evaluation Model Regnal sis Lar e Break LOCA LBLOCA By letter L-90-434 dated December 20, 1990, Florida Power and Light Company (FPL) reported a peak clad temperature of 2171'F in the event of a worst case large break LOCA (LBLOCA) transient.

This value included a calculated temperature of 2051'F plus 120'F increment due to reduced safety injection flow, increased containment spray flow, transition core penalty, containment purge coincident with a LBLOCA, increased steady-state pressurizer pressure uncertainty band and LOCTA coding errors.

Westinghouse recently performed a reanalysis of Turkey Point's worst case Large Break LOCA using the fuel assembly spacer grid model in the BART LBLOCA analysis code. The new analysis included reduced safety injection flow, increased containment spray flow, and elimination of the LOCTA coding errors. In addition, Westinghouse reassessed the remaining evaluations performed to the LBLOCA analysis of record. The results of the reanalysis for Turkey Point Units 3 and 4 resulted in a peak clad temperature of 2132'F. This value includes a calculated temperature of 2082'F plus 50'F increment due to containment purging, steady state pressurizer pressure uncertainty, transition core penalty and steam generator tube collapse during an earthquake.

The large break LOCA analysis as described in the FSAR was originally performed by Westinghouse in 1983 using the BART computer model without spacer grids.

Small Break LOCA SBLOCA By letter L-90-434 dated December 20, 1990, Florida Power and Light Company (FPL) reported a peak clad temperature of 2060'F in the event of a worst case small break LOCA (SBLOCA) transient.

This value included a calculated temperature of 1605'F plus 455'F increment due to delayed AFW Enthalpy Switchover, AFW initiation delay time, open blowdown sample lines, thimble plugs removal, increase in allowed containment temperature, increase in pressurizer pressure uncertainty, transition core penalty, reduced fuel rod gap pressure, power increase due to K(z) discrepancy and LOCTA coding errors.

L-91-165 Attachment Page 2 of 4 Westinghouse recently performed a new Turkey Point Small Break LOCA analysis using the NOTRUMP digital computer code. Peak clad temperature calculations were performed with the LOCTA-IV code using the NOTRUMP calculated core pressure, fuel rod power history, uncovered core steam flow and mixture heights as boundary conditions. The results of the limiting small break LOCA analysis is a maximum calculated peak clad temperature of 1749'F. This value translates into a reduction in peak clad temperature of 311'F for the small break LOCA transient.

~Summar The revised peak clad temperatures of 2132'F for the worst case large break LOCA and 1749'F for the worst case small break LOCA are summarized in Tables 1 and 2 (enclosed) . These results are below the limit of 2200'F in accordance with the acceptance criteria of 10 CFR 50.46.

L-91-165 Attachment Page 3 of 4 TABLE 1 TURKEY POINT UNITS 3 AND 4 PREDICTED PEAK CLAD TEMPERATURES CURRENT LBLOCA EVALUATIONS THAT HAVE ASSESSED PCT PENALTIES Analysis of Record 2051'F Evaluations s ecified in L-90-434 3 HHSI TO 2 HHSI Pumps 9' Increased Containment Spray Flow 15 F Reduced LHSI/RHR Flow 32 F Effect of Containment Purging 9 F Implementation of Debris Resistant FA 3oF Pressurizer Pressure Uncertainty SOF Transition Core Penalty 10 F Further Reduced RHR Flow 7 F LOCTA Coding Errors 25oF Stainless Steel Rods Cycle 12 Fuel 2 F Total LBLOCA PCT specified in L-90-434 2171 F LBLOCA Regnal sis since issuance of L-90-434 Analysis of Record 2082'F Evaluations:

Effect of Containment Purging 9 F Pressurizer Pressure Uncertainty SoF Implementation of Debris Resistant FA 3 F Transition Core Penalty 10 F Stainless Steel Rods in Fuel Assemblies 2'F Generator Tube Collapse During an 'team Earthquake 18oF Total Estimated LBLOCA PCT 2132'F

~, r L-91-165 Attachment Page 4 of 4 TABLE 2 TURKEY POINT UNITS 3 AND 4 PREDICTED PEAK CLAD TEMPERATURES CURRENT SBLOCA EVALUATIONS THAT HAVE ASSESSED PCT PENALTIES Analysis of Record 1605 F Evaluations s ecified in L-90-434 Open Blowdown Sample Lines 19'F Thimble Plugs Removal 21~F Increase- in Allowed Containment Temperature 31 F Pressurizer Pressure Uncertainty 13 F Implementation of Debris Resistant FA 27 F Delayed AFW Enthalpy Switchover 223'F Increase in AFW Initiation Delay Time 50'F LOCTA Coding Errors 250F Reduced Reload Gap Pressure 4 O' Stainless Steel Rods Cycle 12 Fuel 2 F Power Increase Due to K(z) Discrepancy 4 F Total SBLOCA PCT specified in L-90-434 2060 F SBLOCA Regnal sis since issuance of L-90-434 SBLOCA Analysis of Record 174 9oF Total Estimated SBLOCA PCT 1749 F