ML19340C095
| ML19340C095 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 11/05/1980 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, NCR-SQN-EEB-802, NUDOCS 8011130391 | |
| Download: ML19340C095 (2) | |
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A e TENNESSEE VALLEY AUTHORITY CH ATTANOOGA. TENNE'SSEE 37401 400 Chestnut Street Tower II November 5, 1980
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' i; O2 Mr. James P 0'Reilly, Director Office of In ection and Enforce:eent
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U.S. Nuclear R latory Comunission Region II - Suit 3100 101 Marietta Stre Atlanta, Georgia 3 03
Dear Mr. O'Reilly:
SEQUOYAH NUCLEAR PLANT UNIT 2 - ERCW PUMP MOTOR RELAYS - NCR SCN EEB 8022 -
FINAL REPORT The subject deficiency as initially reported to NRC-0IE Inspector R. W. Wright en October 6,1980, in accordance with 10 CFR 50.55(e).
Enclosed is our final repcrt.
If you have any questions, please get in touch with D. L. Lanbert at FTS 857-2581.
Very truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills, Manager Nuclear Regulation and Safety Enclosure cc:
Mr. Victor Stello, Director (Enclosure Office of Inspection and Enforcement U.S. Nuclear Regulatory Comuniasien Washington, DC 20555 Qo11 3
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ENCLOSURE 1
SEQUOYAH NUCLEAR PLANT UNIT 2 ESSENTIAL RAW CCOLING WATER PUMP MOTOR RELAYS NCR SGN EEB 8022 l
FINAL REPORT Descriptien of Deficiency General Electric type IAC66 overcurrent relays with a tap range of 1.5 to 3.0 amperes were installed as part of the 6900 volt shutdown board. These relays formed the overcurrent protecticn system for the 600-hp essential raw cooling water (ERCW) pump motors located in the original ERCW pumping station. A new ERCW pumping station has been constructed with net ERCW pump motors rated at 700 hp.
These new 700-hp ERCW pump motors were installed using the existing overcurrent protection system designed for the original 600-hp ERCW pump motors. The original oveccurrent relays are not adequate to handle the increased amperage associated with the new 700-hp ERCW pump motors.
Safety Implications The increased a=perage associated with the new 700-hp ERCW pump motors has resulted in the annunciation contacts being picked up and braced together during normal operation.. If an ERCW pump motor were to be shut down, it would not be possible to restart the motor because of failure of the relay
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contact to reopen. This condition could adversely affect the safe opera-tien of the plant because of insufficient essential raw cooling water.
Corrective Action For the 700-hp ERCW pump motors that are now in operation, the overcurrent relays have been changed out with General Electric type IAC66 overcurrent rolays with a tap range of 2.5 to 5.0 amperes. It has been verified that this range will allow the ERCW pump motors to start without damage to the relays and will coordinate with existing upstream protective devices.
The remaining relays will be enanged out with relays qualified to handle the increased amperage before final switchover to the new ERCW pumping station.
l TVA has taken action to prevent the recurrence of a similar problem by the issuance of engineering procedure (EP) 4.02.
This EP requires an impact justification sheet to accompany all Engineering Change Notices (ECN's).
This sheet lists all consequences the ECN will have en existing design and will allcw TVA to identify any systems or components which could be affected by the ECN.
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