ML20116G192
| ML20116G192 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 03/26/1985 |
| From: | Hufham J TENNESSEE VALLEY AUTHORITY |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| NUDOCS 8505010405 | |
| Download: ML20116G192 (2) | |
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i TENNESSEE VALLEY AUTHORITY CHATTANOOGA, TENNESSEE 37401 400 Chestnut Street Tower II 35M,2 N March 26, 1985 BLRD-50438/83-09 BLRD-50439/83-06 U.S. Nuc1 car Regulatory Commission Region II Attn:
Dr. J. Nelson Grace, Regional Achinistrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323
Dear Dr. Grace:
BELLEFGITE NUCLEAR PLANT UNITS 1 AND 2 - BACKFLOW NOT CONSIDERED FOR ERCW B0OSTER PUMP SHUR 0FF - BLRD-50438/83-09, BLRD-50439/83 FINAL REPORT The subject deficiency was initially reported to NRC-0IE Inspector L. Watson on December 30, 1982 in accordance with 10 TR 50.55(e) as NCR BLN BLP 8233. This was followed by our interim reports dated Jantary 28 and May 6,1983, July 17,1984, and Febr.iary 22, 1985.
Enclosed is our final report.
.If you have any questions, please get in touch with R. H. Shell at FTS 858-2688.
Very truly yours, TENNESSEE VALLEY AUTHORITY
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1e J. W. Hufham, Manager Licensing and Regulations Enclosure oc:
Mr. James Taylor, Director (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Records Center (Enclosure)
Institute of Nuclear Power Operations 1100 Circle 75 Parkway, Suite 1500 Atlanta, Georgia 30339 g5010405850326 ADOCK 05000438 g
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An Equal Opportumty Employer
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ENCLOSURE BELLEFCNTE NUCLEAR PLANT UNITS 1 AND 2 BACKFLOW Nor CONSIIERED FOR ERCW B0OSTER PUMP SHUR 0FF i
BLRD-50438/83-09, BLRD-50439/83-06 10 TR 50.55(e)
NCR BLN BLP 8233 FINAL REPORT Description of Deficiency During design of the essential raw cooling water (ERCW) system for Bellefonte Nuclear Plant (BLN), consideration was not given to booster pump shutdown and the prevention of backflow. Thus, during loss of offsite power or during routine maintenance, the pumps could shut down thereby resulting in backflow.
A check valve should have been placed in the discharge lines of the booster pumps to prevent backflow when the pumps shut down.
1 TVA has determined that the cause of this problem was that the designers had considered that these pumps would operate continuously and would not require backflow prevention.
Safety Inclications Backflow could cause water hammer, possibly damaging the ERCW heat exchangers in the reactor building or the auxiliary control room air-conditioner.
Damage to these heat exchangers could adversely affect the safe operation of the plant.
Corrective Action TVA has revised all necessary piping drawings and design criteria diagrams to include check valves in the discharge of the ERCW booster pumps. TV A has also mvised applicable seismic analysis drawings to include the check valves and has completed the redesign of affected seismic supports.
Additionally, check valve procurement documents have been issued. All of this work was completed under engineering change rotice (E01) 1718.
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To prevent recurrence of this deficiency, TVA has reinstructed designers to consider pump shutdown as an operating mode in the preparation of BLN design criteria diagrams.
All construction work necessary for completion of this iten will be completed by November 29, 1985, for unit 1, and by March 11, 1988 for unit 2.
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