ML20063D031
| ML20063D031 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 08/19/1982 |
| From: | Oprea G HOUSTON LIGHTING & POWER CO. |
| To: | Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, ST-HL-AE-872, NUDOCS 8208270454 | |
| Download: ML20063D031 (4) | |
Text
.
The Light Company n,,,sa>,, ugiin,ig u-m m,x nuo n.>iisu,,.wxaooummn August 19, 1982 ST-liL-AE-872 File Nunber: G12.126 SFN: V-0530 l
r f
l l
Mr. John T. Collins Regional Administrator, Region IV E20M l
Nuclear Regulatory Connission 611 Ryan Plaza Dr., Suite 1000 J u,.
tb},
L j
Arlington, Texas 76012
Dear Mr. Collins:
South Texas Project 1
Units 1 & 2 Docket Nos. STN 50-498, STN 50-499 First Interin Report Concerning the Essential Cooling Water Strainer Backwash Discharge Line On July 23, 1982, pursuant to 10CFR50.55(e), Pnuston Lighting &
Power Company (HL&P) notified your office of an ite i concerning the Essential Cooling Water (ECW) self-cleaning strainer backwash discharge I
lines.
Attached is the First Interim Report which provides several alternatives for corrective actions which are currently under review.
The final report will provide the corrective action which will be implemented and will be subnitted to your office by January 28, 1983.
If you should have any questicns concerning this iten, please contact Mr. Michael E. Powell at (713)877-3281.
Very truly yours, f
se 2
W.
- prea, Executive, ce President MEP/ng Attachnent
/h Y
G208270454 820819 PDR ADOCK 05000499 S
lionston I.igliting & Power ComI>any cc:
G. W. Oprea, Jr.
August 19, 1982 J. H. Goldberg ST-HL-AE-872 J. G. Dewease File Number: G12.126 J. D. Parsons Page 2 D. G. Barker C. G. Robertson P,. A. Frazar J. W. Williams R. J. Maroni J. E. Geiger R. L. Ulrey S. M. Dew J. T. Collins (NRC)
D. E. Sells (NRC)
W. M. Hill, Jr.
(NRC)
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 Comission Washington, D. C. 20555 G. W. Muench/R. L. Range Charles Bechhoefer, Esquire Central Power & Light Company Chairman, Atomic Safety & !.icensing Board P. 0. Box 2121 U. S. Nuclear Regulatory Commission Corpus Christi, Texas 78403 Washington, D. C.
20555 H. L. Peterson/G. Pokorny Dr. James C. Lamb, III City of Austin 313 Woodhaven Road P. O. Box 1088 Chapel Hill, North Carolina 27514 Austin, lexas 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. 0. Box 808, L-46 Livermore, California 94550 Brian E. Berwick, Esquire William S. Jordan, III t
Assistant Attorney General Harmon & Weiss for the State of Texas 1725 I Street, N. W.
P. O. Box 12548 Suite 506 Capitol Station Washington, D. C.
20006 Austin, Texas 78711 Lanny Sinkin Citizens for Equitable Utilities, Inc.
Citizens Concerned About Nuclear Power c/o Ms. Peggy Buchorn 5106 C3sa 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 08-09-82 1
FIRST INTERIM REPORT CONCERNING THE ESSENTIAL COOLING WATER STRAINER BACKWASH DISCHARGE LINES I.
SUMitARY I
Six (6) non-nuclear safety (NNS) lines were identified as important for the proper functioning of the safety-related Essential' Cooling Water System (ECWS). As presently designed, these lines have the potential to drain significant amounts of water from the Essential Cooling Pond (ECP) and inhibit the ability of the ECWS to cool the safety-related components serviced by the ECWS. Several alternatives for resolution of this problem are outlined in Section III of this report.
II.
DESCRIPTION OF THE INCIDENT On July 23, 1982, pursuant to 10CFR50.55(e), Houston Lighting & Power Company (HL&P) notified your office of an item concerning the ECW self-cleaning strainer backwash discharge lines.
A portion of each ECW self-cleaning strainer backwash discharge line is NHS and non-seismic category I.
These lines run from the ECP intake structure to the ECP discharge structure, and are currently routed underground outside of the ECP embankment. During a seismic event the 4
i portion of the lines that is NHS must be assumed to fail, which may either restrict the backwash flow or discharge the flow outside of the embankment.
Failure of a backwash discharge line may result in a loss of water from the ECP in excess of the maximum 30-day losses assuned in the ECP analysis.
Restriction 'of flow through a backwash line may result in blockage in the ECW self-cleaning strainer; which may ultimately result in the sustained (but temporary) loss of that ECW train.
III.
CORRECTIVE ACTION The following alternatives are under consideration as resolutions to the problems identified herein.
A.
The lines may be upgraded to safety class 3 and seismic category I with the routing left as presently designed. This would involve the replacement of the piping and the temporary removal of a section of the ECP embankment.
B.
The line may be upgraded to safety class 3 and seismic category I with the routing changed so that the lines pass over top of the ECP embankment. This would involve the
-replacement of the pipe and the use of seismic supports on the embankment.
,..s C.
The lines may be rerouted so that they stay within the perimeter of the ECP embankment.
In this case, the lines could remain NNS; however, seismic supports night be required to preclude the possibility that a broken pipe could damage any safety-related equipment or structure.
IV.
RECURRENCE CONTROL A recurrence control program is not considered necessary because the situation is unique.
V.
SAFETY ANALYSIS Of the two scenarios defined in Section II, the " worst-case" scenario is the failure of the backwssh line which results in a loss of water from the ECP in excess of the maximum 30-day losses assumed in the ECP analysis.
The subject lines are non-nuclear safety and non-seismic category I; therefore, for the purpose of this safety analysis, all six lines are assumed to fail during a single seismic incident.
This failure could cause the discharge of backwash flow outside of the ECP embanknent. This continuous loss, coupled with the 30-day fluid losses assumed in the ECP analysis and the lack of a safety-related makeup source, could significantly affect the volume of water in the ECP. Study of this postulated occurence has indicated the following consequences.
A.
Inability to keep ECW temperatures low enough during the 30-day post-accident period to adequately cool the safety-related components serviced by the ECWS.
B.
Inability to maintain the ECP level high enough during the 30-day post-accident period for the ECW pumps to function.
A change in indicated ECP level could be the first indication of a failure of these lines. The loss in level could be as much as six to twelve inches before positive indication is determined.
This loss is too high to maintain adequate margin, given lowest usable initial level, maximum evaporation and seepage rates, and no makeup to the ECP for 30-days.
The design described herein was released for construction on piping composites and has the potential to unacceptably impair the operation of the safety-related ECWS.
_ _ _ _ _ _ _ _ _