ML20079K415
| ML20079K415 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 07/02/1981 |
| From: | Dutton D GEORGIA POWER CO., SOUTHERN COMPANY SERVICES, INC. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-83, REF-SSINS-6820 10CFR-050.55E, 10CFR-50.55E, GN-136, IEB-81-02, IEB-81-2, NUDOCS 8301070465 | |
| Download: ML20079K415 (6) | |
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Vogtle Project soutecta Cuaipaar Svevices. Inc, Pcst Otti:e lion 2625 Cism.ngnam. Airbama 35202 Tescohene 20S ti10 6011 i
July 2, 1981 IE FILE COPl.
United States Regulatory Ccmmission Office of Inspection and Enforcement Region II - Suite 3100' 101 tiarietta Street At1cata, Georgia 30303 o
Attention: for. James P. O'Reilly File: X7BG03-f417 Lcg:
Gfi-136 P.eference:
50-424; 50-425 Westinghouse 4" Gate Valve Closure Problem-Part 10rFR50.55(e) Evaluation and Respcnse to I.E.Bulletin 81-02.
Gentle 1.en:
Further to our f4 arch 19,1981 and May 1,1981 letters, enclosed is
'N Georgia Power Ccmpany's evaluation of the 4" gate valve closure problem.
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This report centains the information required by Parts 10CFR50.55(e) and ICCFR21 and I.E.Bulletin 31-02.
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t!est;nghcuse has stated the failure of the valve to close would invalidate the safety analysis, but has been unable to develop plant specific consequences as required by the bulletin.
Georgia Fcwer Company conside'rs these vaives a reportable deficiency and a reportable safety hazard.
Georgia Power Cenpany submitted an eval-cation for Westinghouse 3" vaivcs on April 21, 1981.
This response contains nc proprietary information and may be placed in the NRC Pubile Document Pcom upon receipt.
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Doug qstten Project General fianager C'.;ii/ r.k r 01HGIlU5 DESIGII W Attac!=ents
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Cei'tified BY 8301070465 82070.e PDR ADOCK 05000424 0
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'.;ettinghouse 4" 03ii Valve Clorure l'roblem July 2,.19B1 page~two.
sees xc:
U.S. Nuclear Regulatory Corsaission Attention: Mr. Victor Stello, Jr., Director Office of' Inspection.-and Enforce:cnt
~ Washington, D.C.. 20555 j
D
- J. H. Miller, Jr.
-1 R. J. Kelly i
R. E. Conway F. G. Mitchell,~Jr.
C. F. Whitmer D. L. McCrary R. A. Thomas J. A.-Bailey' i
O. Satum D. E. Dutten Y,. M. Gillespie
- i E. D. Groover L. T. Gucwa M.-Z. Jeric B. L. Lex
' C. R. Miles, Jr.
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R. N. Staffa J. L. Vota
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TVALUAT10H FOR PGTEtiTIAL DEFICIEtiCY n.
J Initial Recort:
On February 12. 1931, deficiency concerning !!astinghouse 4" gate n ives.Mr. John Rausch, H
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of a potential Bacharound:
The El:D manufactured gate valve closing prcble everal valves ducir.g plant start-up testing at the Almara; Huclear Station in Spain conditions the EPP.I POR',' bicck valve tests at Duke Pouer's liarshall Station.
Typically, these-and during of the fica passage unsealed. valves operated through 75 percent i
1 thrust loads required to fully close the valve to be 50 percent lSubseq percen t.
des'gn calculations predicted, arger than original In these original design calculations, the stem thrust required to fu m
wedge or disc against flow we.s calculated using t. hat were considered eat the c:andard equaticns which are'part of the actuator manufacturer's sizi e industry This calculated required stem thrust load was then used to size the Li it rotoe operator that scuers the valve.
m orque-actual required thrust load to be 50 percent higher than the ' calcu e
s.as used to size the operators, the operators do not have the capacity to which close the valve particularly under their difficult 90 perce u
y.
of analyses and tes:s were initiated.To determine the source 'of th n.wg s, a series full flw testing, mechanical fixture testing, seat friction incicde:
tnd : otor cperatcr testing.
Although this work is not totally complete, e
ng rave been performed.
higher than expected seat friction forces are the source of th
(<ctss load.
Back. seat friction reactions and stem-disc connec
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e majority of the cen:ribute.
Cesign-wise. little can ba done to reduce the actual required loads so focus en increasin re:
, the valve being con:g tile force capabilities of the valve actuators.
ention iderad, the force capability can be increased by someDeper. ding umbina. ion of gearing char.ges, motor size changes, cnd operator fram ensnges.
In scme valve sizes these changes have potential for overstress pg:s so other changes to the valve may also be required ve
,Egineering Enluation(
T!.: failure of the valves to close could invalidate the '.cstinghouse safety analys
- a valves affected are
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. E'!AlbaTIO:I FOR POTEt;TIAL DEFICIEllCY
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Valve-WEMD' Location i Model Valve Function
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. Number Reference
- f Boron Injection Tank Isolation 8201A'
.4GM88
-s 88018 4GM88
- SI. Pump Hot Leg Recirculation Isolt. tion 8802A 4GM38 88028
'4GM88 Scron Injection Tank Isolation 8803A 4GMS8 88033 4GM88 t
SI Pump Discharge x 0 Isolation 8821A 4GMS7 8821B 4GM87 SI Pump CC Injection Isolation 8835 4GMS8 Reportability:
Since the failure of the. valves to close could invalidate the Westinghouse safety analysis, these valves represent c deficiency found in the design and construction -
1 mwhich, were it to have retaincd uncorrected, could have adversely affected the ^ safety"
' f pperations of the nuclear power plant at any tirce throughout the expected lifetice i
of'the plant.
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The 4" gate valve closure problem also'represcnts a significant deviation from performance
- pecificaricns which uill require extensive evaluation and repair to establish the adequacy of these cor.p:nents to perform their intended safety function.
~_Corecctive Action:
Westinghouse is currently' conducting flow tests to determine the modifications necessary to cic:e the valves. Note that in the b;ckground discussion, the requirement for closing against the criginal equip: rent spec.ification is extremely conservative and -
Only a scall percentage of the valves will be made capable of-closing against the origin;i ecuip: rent specification.
Vestinghcuse has furnished the folloaing reco= ended correctiva c.ction!.
Georgia P0, er Ccmpany uill modify the valves to those-requirements or to other r; quire..ents which are daveloped by Westinghouse through the 4" valve test-ir.g pregcam. 11odificati:ns are expected to be completed by March 1932.
Madel /G..87 (Tenta tive):
- 1. Change operator gear ratio to guarantee adequate thrust capability at 80 percent vol tace.
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'.- Rewire the operator for limit cicsing control.
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. C 21.'. A!:0': FOR '. ~iT! L :NLb?ICIEf;CY.
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.- S'-$el :'s'G3 -(Ten::iive) :
1.
Cr.ar. e te Li-.itor:;ue 5B-0-25 motor-operator.
2.
Kwire-:he c:erator. for limit closing control.
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31 Char.ge to new ycke.that will-accept an SB-0-25.
4 C5 cage valve internals to accept higher operator stall loads.
a.
i;ew stem (same size:
1.25" 9).
b.
Isw sten disc cor.nection Renachined valve. disc.to accept new stea-disc ccnnection parts c.
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" ACTIVE" VALVE. APPL $ATIONS Ir r
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MAXIMUMAP(PSlO)
AS FLOW APPROACl!ES ZERO VALVE CAPA0!LITY VALVE WEMD t.P (PSID) BELOW WrilCH SATISFIES FINICTICII:
VALVE LOCATI0il Il0 DEL ' '
EQUIPMElli FU;iCTI0flAL(1)
VALVE WILL CLOSE REQUIREMEitT FUllCTIO1
.tiUMBER REFEREtiCE SPECIFICATI0li REQUIREHEllT (AS SHIPPED)
(AS SIIIPPED) 1 Boron injection 8801 4GP38 2750 1200 750 No
- bTank Isolation A&8 l
4GM88 2750 1200 750
!!o SI Pump Hot Leg 8802 i
Recircula tion A&B Isolation Boron Injection 8803 4GVS8 2750 1200 750 flo Tank Isolation A&B I
SI Funp 8821 4Gl'a7
.1500 l500' 750 lb Discliarge A&8 x 0 Iso.1ation (cross over)
- L *.,
.2750
,1200 750 fla Injec tion Isolation
- 0TE:
' ' t) FunctioEal requirements untier final review.
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