ML20039B190
| ML20039B190 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 11/27/1981 |
| From: | Goldberg J HOUSTON LIGHTING & POWER CO. |
| To: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| REF-SSINS-6820 IEB-81-02, IEB-81-2, ST-HL-AE-756, NUDOCS 8112220394 | |
| Download: ML20039B190 (6) | |
Text
i The Light Company n_,,,,, u#mim,_ m H.,a= noi
,,,.w an amun November 27, 1981 ST-HL-AE-756 SFN: V-0540 Mr. Karl Seyfrit s$
c3 Director, Region IV g'
Nuclear Regulatory Commission Q
7_s 611 Ryan Plaza Drive, Suite 1000 DEC 211931% -
Arlington, TX 76012
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Dear Mr. Seyfrit:
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'a South Texas Project ji Units 1 & 2 Docket Nos. STN 50-498, STN 50-499 Response to NRC IE Bulletin No. 81-02, Supplement 1 Bulletin No. 81-02, Supplement 1, received August 21, 1981, bas been reviewed by Houston Lighting & Power Company. Investigation has ccnfirmed that a number of the Westinghouse EMD gate valves discussed in the Bulletin have been purchased for installation at the South Texas Project.
The attached table lists the subject valves intended for us. in safety-related systems, their planned service, the differential pressure against which they will be required to close, and the safety consequences of the valves failing to close.
The af fected valves will be modified by Westinghouse so that they will be capable of closing against the maximum differential pressures that will be encountered.
The exact method that will be used has not yet been firmly established.
However, Westinghouse is currently working on a schedule under which the modifications to the affected valves will be completed by Decem-ber 31, 1982.
The manpower expended in the review of this supplement to the Bulletin and the preparation of the report is estimated to be approximately 100 man-hours to date.
This estimate only includes activities specific to STP and not generic work performed by W.
Since corrective actions have not been completed, a breakdown of the man-hours expended is not available.
If there are any questions, please contact Mr. Michael E. Powell at (713) 676-8592.
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D 2 5 l98I J. H. Goldberg Vice President
_2. s Nuclear Engineering & Construction
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PLW/blt Attachment 8112220394 eii127" PDR ADOCK 05000 G
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llouston Lighting & Power Company cc:
G. W. Oprea November 27, 1981 J. H. Goldberg ST-HL-AE-756 J. G. Dewease SFN: V-0540 D. G. Barker Page 2 C. G. Robertson H. Pyle, III R. A. Frazar D. R. Beeth J. W. Williams J. W. Briskin J. E. Geiger D. E. Sells (NRC)
H. S. Phillips (NRC)
J. O. Read (Read-Poland, Inc.)
M. D. Schwarz (Baker & Botts)
R. Gordon Gooch (Baker & Botts)
J. R. Newman (Lowenstein, Newman, Reis, & Axelrad) -
STP RMS Director, Office of Inspection & Enforcement Nuclear Regulatory Commission Washington, D. C. 20555 R. L. Range /G. W. Muench Charles Bechhoefer, Esquire Central Power & Light Company Chairman, Atomic Safety & Licensing Board P. O. Box 2121 U. S. Nuclear Regulatory Co= mission Corpus Christi, Te'xas 78403 Washington, D. C.
20555 R. L. Hancock/G. Pokorny Dr. James C. Lamb, III City of Austin 313 Woodhaven Road P. O. Box 1088 Chapel Hill, North Carolina 2751' Austin, Texas 78767 J. B. Poston/A. vonRosenberg Mr. Ernest E. Hill City Public Service Board Lawrence Livermore Laboratory P. O. Box 1771 University of California San Antonio, Texas 78296 P. O. Box 808, L-46 Livermore, California 94550 Brian E. Berwick, Esquire William S. Jordan, III Assistant Attorney General Harmon & Ve~cs for the State of Texas 1725 I Street, N. W.
P. O. Box 12548 Suite 506 Capitol Station Washinton, D. C.
20006 Austin, Texas 78711 Lanny Sinkin Citizens for Equitable Utilities, Inc.
Citizens Concerned I. bout Nuclear Power c/o Ms. Peggy Buchorn 5106 Casa Oro Route 1, Box 1684 San Antonio, Texas 78233 Brazoria, Texas 77422 Jay Gutierrez, Esquire Hearing Attorney Office of the Executive Legal Director U. S. Nuclear Regulatory Commission Washington, D. C.
20555 Revision Date 10-29-81
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ATTACHMENT SOUTH TEXAS PROJECT a,
RESPONSE TO NRC IE BULLETIN 81-02, SUPPLEMENT 1 W-EMD PLANNED SERVICE MAXIMUM VALVE IP_
APPCICATION HL&P VALVE # (W)
AP (psi)
FAILURE ANALYSIS 3GMB8FNB Pressuriter PORV Block Valve XRC 001 A, B 2500 The present design does not require the block valves to close
, (i.8000 A,B) under full flow conditions. These valves are used to isolate PORV's if they are leaking. The failure of one of these valves to close under full flow conditions would be the same as a Failed Open PORV (assuming PORV is already opened and fails to close). The consequences of this failure are covered by present accident analysis in the FSAR.
6GM72FBA Volume Control Tank Discharge XCV 112 B 100 These valves in series are located on the VCT Discharge line Isolation (LCV-112 B) that provides suction to the CVCS charging pumps. These XCV 113 A valves are closed upon opening of the valves that permit CVCS (LCV-113A) chargina pump suction from the RWST and when either SI signal or VCT 10-10 level signal is present. Failure of one valve to close completely may reduce the differential prersure across the second valve sufficient to permit its cicsure. Fail-ure of these valves to close would have,,o significant safety consequences.
6GM72FBA CVCS Charging Pump Suction to XCV 112 C 200 These valves are in parallel flow paths from the R4ST to the RWST (LCV-112C)
CVCS charging pump suction header. These valves c.re normally XCV 113 B closed and are used only in abnormal situations when the (LCV-1138) charging pumps are used to provide water from the RWST to the Reactor Coolant System. These valves are interlocked to prevent closure when an SI signal or VCT 10-10 level' signal is present. Failure of these valves to close would have no significant safety consequences.
4GM8dFND CVCS Letdown Upstream of LCV 465 2500 These two valves in series provide isolation of the CVCS let-Regenerative Heat Exchanger LCV 468 down from the RCS. These valves would be automatically closed on Pressurizer low level that might be caused by a break in the safety class 2 pipe of the regenerative heat exchanger downstream of the valves. The two valves in series provide redundancy. Failure of one valve to close completely may re-duce the differential pressure across the second valve suf-ficiently to pennit closure. If the blowdown is not h
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- p. 2 of 4 W-EMD PLANNED SERVICE VALVE ID APPLICATION HL&P VALVE # (W) hyfpM FAILURE ANALYSIS tenninated, the consequences are covered by present accident analyses in the FSAR. Failure of the valves to close cce-pletely has no erreviewed safety consequences.
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CVCS Letdown Containment 150-XCV023 700 These valves provide a Containment Isolation function. High 4GM74FEB lation Valves (8133) differential pressure would occur on a Containment isolation XCV024 Signal. For a pipe break inside Containment, the differen-
' (8134) tial pressure across the valves would be reduced insnediately.
permitting the valves to close.
For failure of the two upstream isolation valves (Westing-house EMD valves) in conjunction with a letdown pipe break outside C w tainment, there are motor-operated packless metal diaphraym valves used as Letdown Orifice isolation valves that could be manually operated to terminate flow. When the flow is reduced, the valves LCV 465. LCV 468. XCV 023 (8133) and XCV 024 (8134) would then be able to close. Also.
partial closure of one valve may reduce the differential across the second valve sufficiently to' permit the second valve to close. Failure of XCV 023 (8133) and XCV 024 (8134) to close would have no significant safety consequences.
4 278FPA CVCS Charging Line Isolation XCV 025 3100 The failure of this valve for a pipe break inside or outside (8135)
Containment reduces the redundancy for Containment Isolation.
For outside Containment, there are 3 check valves downstream that would prevent blowdown of the RCS. For inside Contain-ment, the Charging Pumps can be stopped and the differential pressure across the valve would be reduced immediately, per-mitting the valve to close.
4GMFBA Charging Pump Suction Valve XCV 218 0
This valve is normally closed and provides a means to have from Boric Acid Transfer Pump (8358)
CVCS Charging Pumps take suction from 4 weight percent boric acid solution. The valve is in series with a check valve; failure to close would permit flow from boric acid transfer pumps to the suction of the charging pumps. Flow may be stopped by turning off the BAT pumps. Backflow into BRS is precluded by check valve. The failure of this valve to close has no significant safety consequences.
- p. 3 of 4 b-iMD PLANNED SERVICE MAX MU VALVE ID APPLICATION HL&P VALVE # (W)
AP fpsh FAILURE ANALYSIS 6
16GM72FBA Safety injection Suction Valve XS! 001 A, B, C 200 Valve is closed for recirculation phase following a LOCA.
from RWST (8801 A.B.C)
Failure of the valve to close would result in a loss of redundancy for preventing backflow to the RWST. Failure of the valve to close has no significant safety consequences.
t 6GM77 FHA High Head Safety Injection Pump XSI 004 A, B, C 100 This valve provides pump isolation and also serves as the Discharge Isolation Valve /
(8804 A.B.C)
Containment Isolation Valve. The valve is normally open.
Containment Isolation Failure of the valve to close against backflow from the RCS has no significant safety consequences because there are 2 check valves which could prevent blowdown of the RCS.
6GM78FNB HHSI to Acc mulator Isolation XSI 006 A, B, C 0
This valve closes for switchover from Cold Leg injection to Valve (8806 A.B.C)
Hot Leg injection. Failure of valve to close during recir-culation will degrade flow to Hot Legs. Pressure differen-tial across valve can be reduced to permit closure by momen-tarily interrupting SI (by stopping pump or manual action).
Failure of the valve to close reduces the redundancy for Hot Leg recirculation.
6GM78FNB HHSI to Hot Leg Injection Iso-XSI 008 A, B, C 0
This valve is opened to provide SI switchover from Cold Leg lation Valve (8808 A.B.C) injection to Hot Leg injection. If switchover back to Cold Leg is required, failure of the valve to close would degrade Cold Leg injection flow. However, SI could be momentarily interrupted to reduce differential pressure across valve permitting it to close.
16GM72FBD Emergency Sump Recirculation XS! 016 A, B, C 100 This v11ve must open to permit SI recirculation. The valve Isolation Valve (8816 A.B.C) is requ red for isolating a passive failure between the sump valve and the next motor-operated valve. High differential pressure should not be present when the valve is required to close.
8GM74FEA Low Head Safety Injection Pump XSI 018 A, B, C 100 This valve serves as a pump isolation valve and as a Contain-Discharge Isolation Valve / Con-(8818 A.B.C) ment Isolation Valve. The valve is normally open. Reverse tainment Isolation Valve flow in the line is stopped by the inside Containment check valve. Failure of the valve to close reduces Containment Isolation redundancy.
- p. 4 cf 4 w.EMD PIAkNrn trDvfrF ggggggy VALVE 10 APPLICATIDM HL&P VALVE f (W) op (psi)
FAILURE ANALYSIS 8GM78FNB LHSI to Hot Leg injection Iso-XRH 019 A. B. C 200 Same as for XSI 008 (B808) lation valve (B819A,B.C1 8GM78FNB LHSI to Accumulator Isolation XRH 031 A. B. C 200 Same as for XS! 006(8806)
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Valve (8901 A.B.C) 12GM78FND Accumulator Tank Discharge Iso-XSI 039 A. B. C 0
This valve is normally open during power operation and is lation (8949 A.B.C) closed only when required to prevent blowdown as RCS is de-pressurized in a normal shutdown. The accumulator may also be depressurized by venting the N2 to the Containment. The failure of the valve to close under high differantial pressure has no significant safety consequences.
12GMB8SEB RHR Suction Isolation Valves XRH 060 A. B. C 700 These valves are normally closed' valves and can only be opened from RCS (9000 A.B.C) when RCS pressure is less than approximately 425 psig. When XRH 061 A. B. C the valves are open, they automatically close when RCS (9001 A.B.C) pressure is approximately 750 psig. If valves fall to close under high differential pressure, the operator can take steps to reduce RCS pressure untti the valves are able to close.
Also, with two valves in series, partial closure of the first valve may reduce differential pressure across the second valve permitting its closure. Failure of these valves to close would reduce redundancy.
8GM74FCA CSS Pump Discharge Isolation XCS 001 A. B. C 200 These' valves are normally closed. They open to provide Cou-Valve / Containment lo31ation Valve (9100 A.B.C) t3inment spray and are used for Containment Isolation after Lontainrent spray has been terminated. A check valve (IRC) would provide isolation capability. Failure of these valves to close reduces Containment isolation redundancy.
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