ML19270G807

Forwards Interim Rept Re Design Basis Accident Movements of Steel Containment Not Properly Accounted for in Design. Next Rept Will Be Made by 790109

ML19270G807
Person / Time
Site:	Sequoyah
Issue date:	06/11/1979
From:	Gilleland J TENNESSEE VALLEY AUTHORITY
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
NUDOCS 7906200342
Download: ML19270G807 (4)

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TENNESSEE VALLEY AUTHORITY CH ATTANOOGA. TENNESSEE 37401 500C Chestnut Street Tower II a

JUN 11 1979 Mr. James P. O'Railly, Director Offica of Inspection and Enforcomant U.S. Nuclear Regulatory Coasnission Engion II - Suite 3100 101 Mariatta Street Atlanta, Georgia 30303 Daar Mr. O'Railly:

SEQUOYAH NUCLEAR PLANT UNITS 1 AND 2 - DBA MOVEMENTS OF STEEL CONTADDMirr NOT PROPERLY ACCOUNTED FOR IN DESIGN - NCR CEB 79 FIRST INTEREf REFORT The subject deficiamey was inirimity reported to NRC-01E Inspector Tom Burdetta on May 11, 1979, in accordanae with 10 CFR 50.55(e).

Enctnsed is our first interim report. We expect to submit our next report by October 9, 1979.

If you have any questions concerning thia matter, please get in touch with D. L. Lambert at FTS 854-2581.

Very truly yours, J. E. Gilleland Assistant Manager of Power Enclosure cc: Mr. John G. Davis, Acting Director (Ecciosure)

Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20535

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SEQUOYAll NUCLEAR PI Ar T UtilTS 1 AND 2 '

D15A !! Ovid!LUTS OF fill.l L CONTAllau:Nr

• NOT PROPERLY ACCOUNitD FOR IN DESIGN '

NCR CEB 79-19 '

10 CFR 50.55(e) FIRST INTERIM REPORT .

Description of Deficiency Piping which penetrates the steel containment vessel (SCV) with rigid penetrations was supported without proper consideration for all lesign basis accident (DBA) movements of the SCV. In the original desc 1 '

the penetrations and their supports, two incorrect assumptions wetc used for analysis. These assumptions and their consequences are described below.

The first incorrect assumption was that DBA movements of the SCV were assumed to be only in an outward direction fron its steady state condi-tion when actually there is movemen; in both the inward and outward directions.

This lack of consideration for all deflections of the SCV has resulted in several supports designed with inadequate clearance in the unrestrained direction and could result in overstressing the pipe and/or penetrations.

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The second incorrect assumption was that the SCV movements would not be severe enough to lock the snubbers.

in fact This means lens pipe flexibility is which inavailable turn maytoresult accocomodate deflection than was originally thought in excessive stresses in the piping and penetra-tions and may also overload the snubbers.

The nonconformance affects 53 penetrations in each unit. The attached table lists 37 affected penetrations which are safety related. The list is identical for units 1 and 2.

safe shutdown.

Eight of those 37 are required for Interita Progress Faced with the necessity to reanalyze, TVA has decided to generate time history novement data for each of the six primary system DBAs at each containment nozzle location. This rigorous analysis will ensure containment inertial as well as displacement ettects on pipe are conser-vatively considered. -

Reanalysis of all affected piping systems and all resulting hardware modifications will be completed before initial criticality.

The applicability of this deficiency on TVA's other PWRs is being evaluated.

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SECUCYAH NUCLEAF FLAiC 1

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S a _f e t y_ F e la t e d Pining Penetraticrs Affected hv NCP CEB 79-19 Fequired Penetratico Pipe For Safe Number Svstem Size Service Shutdown 16 CVCS (supply) 3 Ecrral charging to Begen Hx Fo 29 CCS (Disen) 6 R.C. Fung Cil Ccoler bo 35 CCS (Cisch) 6 Excess letdown Hx Yes 40A AFk (Supply) 4 Feedwater Bypass Yes 40F AFk (Supply) 4 Feedwater Bypass Yes 43A CVCS (supply) 2 Sealwater Injecticn - FC Purp 50 4 3E CtCS (Supply) 2 Sealwater Injection - EC Pung Fo 43C CVCS (supply) 2 Sealwater Injection - RC Pump Ec 43C CVCS (Supply) 2 Sealwater Injection - FC Pung Fo 44 CVCS (Cisch) 4 Sealwater Return - FC Pump No 48A Contain7ent Spray 12 Spray Header Yes 483 Ccn ta intre n t spray 12 Spray Header Yes 49A FHF Sprav 8' Spray Header Yes 49F FHB Spray 8 Spray Header Yes SOA CCS (Cisch) 3 FC Furp Thermal Barrier bo 500 CCF (Supply) 3 FC Fump Thermal Earrier Fc 52 CCS (supply) 6 BCP, CPCM, Lower Cont. Vent Ccoler Fo 53 CCS (Supply) 6 FCP, CRCM, Lower Cont. Vent Cooler Yes Sc E3Cv (Supply) 6 RCP, CBCM, Lower Cont. Vent Ccoler No 57 EFCv (Cisch) 6 FCF, CRbM, Lower Cont. Vent Cooler Ec 58 EFCv (Supply) 6 FCP, CFCM, lower Cont. Vent Ccoler Eo 59 EFCk (Disch) 6 FCP, CRCM, Loker Cont. Vent Cooler Ec 60 3 EECv (Supply) 6 FCP, CFCM, Lower Cont. Vent Cooler Ec 61 EECF (Cisch) 6 FCP, CRCM, Lower Cont. Vent Cooler Ec 62 cj' EFCk (Supply) 6 FCP, CBCM, Lower Cont. Vent Cooler 50 63 t, EFCk (Disch) 6 FCP, CBCM, Lower Cont. Vent Ccoler 6c oa EBCk (Supply) 2 Upper Containment Vent Cccler No 09 L2 EFCk (Supply) 2 Upper Containment Vent Cooler hc 70 tea EFC5 (Cisch) 2 Upper Containment Vent Ccoler Fo 71 'sJ EPCb (Cisch) 2 Upper Containment Vent Ccoler Ec 72 EFCk (Cisch) 2 Upper Containtrent Vent Ccoler Eo 73 EFCv (Disch) 2 Upper Containaent Vent Ccoler No

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SECUOYAH NUCLEAR PLANT ,

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Safety Related Picing Penetrations Affected hv NCR CEB 79-19 Fequired Penetration Pipe Fcr Safe Numter Systen- Size Service Shutdown 74 EFCK (Supply) 2 Upper Containment Vent Ccoler Uc 75 EFCE (Supply) 2 Upper Containment Vent Ccoler Eo 82 Fuel Focl Cooling 6 From Fefueling Cavity No 83 Fuel Pool Ccoling 4 To Fefueling Cavity bc 110 S I S - U II I (Supply) 2 Frcm CVCS Disch to UHI Fo e

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