ML20040C633
| ML20040C633 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 01/19/1982 |
| 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 8201290104 | |
| Download: ML20040C633 (2) | |
Text
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TENNESSEE VALLEY AUTHORITY
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Dear Mr. O'Reilly:
W BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - AUTOMATIC DIESEL START FROM AUXILIARY CONTROL ROOM - BLRD-50-438/81-48, BLRD-50-439/81 SECOND 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 This was followed by our first interim report dated August 19, 1981. Enclosed is our second interim report. We expect to submit our next report by June 17, 1982.
If you have any questions concerning this matter, please get in touch with R. H. Shell at FTS 858-2688.
Very truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills, Marager Nuclear Regulation and Safety Enclosure cc:
Mr. Richard C. DeYoung, Director (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Commissior Washington, DC 20555 8201290104 820119 PDR ADOCK 05000438
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1 An Equal Opportunity Employer
-J 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 SECOND 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 (MCh) 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 Control 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 ctuse 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 review and correct all affected drawings under ECN 1?O9. The correct de. ign vill be issued and will properly reflect the design criteria.
Action required to prevent recurrence will be addressed in nonconfo*mance report BLRD-50-438/81-30 and BLRD-50 439/81-33 (BLN QAB 8101).
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