ML20030B763
| ML20030B763 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 08/19/1981 |
| 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, NUDOCS 8108240197 | |
| Download: ML20030B763 (2) | |
Text
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TENNESSEE VALLEY._ AUTHORITY r
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r; CH ATTANOOGA, TENN ESSEE 47.4ol 400ChestnutStreetTowerII' I I ' ' 2!l il fj. l /
August 19, 1981
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BLRD-50-438/81-48 BLRD-50-439/81-51 il AUG g 4 7
Mr. James P. O'Reilly, Director 5
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Region II - Suite 3100 101 Marietta Street Atlanta, Georgia 30303
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Dear Mr. O'Reilly:
BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - AUTOMATIC DIESEL START FROM AUXILIARY CONTROL ROOM - BLRD-50-438/81-48, BLRD-50-439/81 FIRST INTERIM REPORT The subject deficiency was initially reported to NRC-0IE Inspector R. V. Crlenjak on July 20, 1981 in accordance with 10 CFR 50.55(e) as NCR BLN BLP 8119 Enclosed in our first interim report. We expect to submit our next repcrt by January 20, 1982.
If you have any questions concerning this matter, please get in touch with D. L. Lambert at FTS 857-2581.
Very truly yours, TENNESSEE VALLEY AUTHORITY p
1s, 6 Nuclear Regul tion and Sa l
Enclosure Mr. Victor Stello, Director YEnclosure) l cc:
Office of Inspection and Enforcement U.S. Nuclear Regulatory Conmission Washington, DC 20555 i
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- 'b PM An Equal Opportunity Employer
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ENCLOSURE BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 AUTOMATIC DIESEL START FROM AUXILIARY CONTROL ROOM 10 CFR 50.55(e)
BLRD-50-438/81-48, BLRD-50-439/81-51 FIRST INTERIM REPORT Description of Deficiency Auxiliary Control System Criteria N4-50-D791, paragraph 4.2, requires that the design shall assume that evacuation of the main control room (MCR) can occur simultaneously or coincidently with the loss of offsite power. Standby AC Auxiliary Power System Criteria N4-RPD775A, paragraph 3.6.4, requires in part that a main bus undervoltage (loss of offsite power) shall start the diesel generator supplying standby power. In the event of the loss of power occurring simultaneously with main control room evacuation, the Solid State Cont"ol System (SSCS) control logic and hardware implementation does not implement both of these requirements.
For the present design, the Class IE medium voltage switchgear bus undervoltage signal intended to automatically start the diesel generator engine is inadvertently disabled by the diesel generator system SSCS logic when the main control room evacuation is initiated. Any subsequent required use of any or all of the diesel generators must be manually initiated from the auxiliary control room.
The apparent cause of the deficiency was a design error. TVA is investigating the possible QA implementations of this and other similar NCR's.
Interim Progress TVA will redesign the system and will review and correct all affected drawings.
Action requirei orevent recurrence will be addressed in nonconformance report BLRD-50-438/81-30 and BLRD-50-439/81-33 (BLN QAB 8101).
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