ML19350D596
| ML19350D596 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 05/07/1981 |
| From: | Oprea G HOUSTON LIGHTING & POWER CO. |
| To: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| REF-PT21-81-422-000 10CFR-505.55E, PT21-81-422, PT21-81-422-000, ST-HL-AE-659, NUDOCS 8105180111 | |
| Download: ML19350D596 (5) | |
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g-f?>-OOd May 7, 1981 ST-HL-AE-659 SFN:
V-0530 Mr. Karl Seyfrit Director, Region IV Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76012
Dear Mr. Seyfrit:
South Texas Project Units 1 & 2 Docket Hos. STN 50 498, ST'i 50-499 Final Report Concerni-c Steam Generator Water _evel Measurement Svsten E rors On April, 8,1981, Houston Lighting & Power notified your office of an iten pursuant to 10CFR50.55(e).
The iteT concerns possible stean generator water level measurement s_ysen errors.r a result of heat up in the reference leg cue to high energy line breaks insice containment.
This iten has previousiv been reported by Westinghouse under the Drovisions of 10CFR21.
The related equiDnent has not been delivered to the South Texas Project.
Attached is tne Final Report which orovides tne corrective actions to be implemented.
If you have any quertions, please contact Mr. 4. E. Powell at (713) 676-8592.
Very truly yours, 3
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/ :?r$a ExecdtiveVicePresident JGW/aaj Attachment 00ROR\\fxQ#,1-a 7)ost 8'O ll t b
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Houston Lighting & Power Company May 7, 1981 cc:
J. H. Goldberg ST-ML-AE-659 D. G. Barker SFN:
V-0530 C. G. Robertson Page 2 Howard Pyle R. L. Waldrop H. R. Dean D. R. Beeth J. D. Parsons L. K. English J. W. Briskin R. A. Frazar STP RMS 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)
Director, Office of Inspection &' Enforcement Nuclear Regulatory Connission Washington, D. C. 20555 M. L. Borchelt Charles Bechhoefer, Esquire President Chairman, Atomic Safety & Licensing Boarc Central Power & Light Company U. S. Nuclear Regulatory Concission P. O. Box 2121 Washington, D. C.
20555 Corpus Christi, Texas 78403 R. L. Range Dr. Janes C. Lanb, III Central Power & Light 313 Woodnaven Road P. O. Box 2121 Chacel Hill, North Carolina 27514 Corpus Christi, Texas 78403 R. L. Hancock Mr. Ernest E. Hill Director of Electrical Utilities Lawrence Livernare Laboratory City of Austin University of California P. O. Box 1088
- o. O. 3ox 808, L-123 Austin, Texas 78767 Livernore, California 194550 T. H. Muehlenbeck Citizens for Equitable Utilities, Inc.
City of Austin c/o Ms. Deqqy Buchorn P. O. Box 1088 Route 1, Box 1684 Austin, Texas 78767 Brazoria, Texas 77422 J. B. Poston Pat Coy Assistant General Manager of Ocerations Citizens Cnncerned About Nuclear Power City Public Service Board 5106 Casa Gro P. O. Box 1771 San Antonio, Texas 78233 San Antonio, Texas 78296 A. vonRosenberg
-Lanny Sinkin City Public Service Board 2207-0, Nueces P. O. Box 1771 Austin, Texas 78705 San Antonio, Texas 78295 drian E. Berwick, Esquire Jay Gutierrez, Esquire
. Assistant Attorney for the State of Texas Hearing Attorney P. O. Box 12548 Office of tne Executise Lacal 9irector Capitol Station U. S. Nuclear Regulatory Connission Austin, Texas 73711 klasnington, D. C.
20555 m,33,3-
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FINAL REPORT CONCERNING STEAM GENERATOR WATER LEVEL MEASUREMENT SYSTEM ERRORS-I.
Summary of Incident Westinghouse identified to HL&P a generic concern (previously reported to NRC under 10CFR21) that Steam Generator Water Level Measurenent System errors could occur because of the heat up of the reference leg after nigh energy line breaks inside contain-ment.
HL&P confirmed that the concern is apolicable to STP.
Although _the subject equipment has not 'been delivered, the concern was reported under 10CFR50.55(e).
A corrective action that can be implemented to resolve the safety concern is to have additional insulation placed on the steam ge.erator level measurement reference leg.-
II.
Description of the Incident By letter dated July. 3,1979, Westinghouse notified HL&P of a generic concern regarding possible Steam Generator Water Level i
Measurement System Errors caused by the heat up of the reference leg by high energy line breaks inside containment.
The heat up will cause the system to be biased such that protecion signals (i.e. reactor trip and auxiliary feedwater initiation) could be delayed or prevented.
Altnougn backuo signals exist, Ine crimary signal provided by the stean generator water level measurenent system cculd be affectec.
The concern was reported to the NRC t
under 10CFR21.
The July 3, 1979 letter also provided recommendations for immedi~ ate corrective action to operating plants.
Subsequent to these letters, HL&P and Westingnouse discussed otner improvenents to the Steam Generator Water Level Measurement Systen which would also preclude tne safety concerns.
5 Although the subject equipment reported on a generic basis by Westinghouse has not been delivered, dL&P re-reported this ; ten under 10CFR50.55(e, to the Region IV office on April 8,1981.
Engineering has determined that the immediate corrective actions recommended for near-term and operating clants are an acceptable resolution for the South Texas Project.
III.
Corrective Acticn The corrective action for the South Texas ?roject will be to I
comply with the Westingnouse recommended actions for near-tern and i
operating plants.
The corrective action involves additional 1.isulation placed on the reference leg.
(Note that alternative resolutions are still being pursued between W and ML3P and nay be incorporated if tney are determined acceotable from a safety concern standpoint and are considered oreferable).
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IV. Recurrence Control A recurrence control program is' not considered necessary because the situation is a unique design.
V.
Safety Analysis A detailed analysis was not performed since the potential level bias could result in delayed protection signals.
Backup signals may be available but the adverse environment could delay or prevent the primary signal arising from declining steam generator water level.
The corrective action will alleviate these potential errors.
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