ML19321A802
| ML19321A802 | |
| Person / Time | |
|---|---|
| Site: | Hatch, Vogtle  |
| Issue date: | 05/08/1980 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | John Miller GEORGIA POWER CO. |
| References | |
| NUDOCS 8007240213 | |
| Download: ML19321A802 (2) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION c
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REGION 11 o,
8 101 MARIETTA ST., N W., SUITE 3100 8
ATLANTA, GEORGLA 30303
- j NAY 8 1980 In Reply Refer To:
RII:JP0 c5tF37175(F36[6x 50-424,~50 42 s
Georgia Power Company Attn:
J. H. Miller, Jr.
Executive Vice President 270 Peachtree Streer, N.W.
Atlanta, Georgia 30303 Gentlemen:
The enciesed Information Notice provides early notification of an event that may have safety significance. Accordingly, you should review the Information Notice for possible applicability to your facility.
No specific action or response is requested at this time; however, con-tingent upon the results of further staff evaluation, a Bulletin or Circular recommending or requesting specific licensee actions may be issued.
If you have questions regarding this matter, please contact me.
Sincerely,
\\ NN9(m /
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_A James P. O'Reilly Director
Enclosures:
1.
IE Information Notice No. 80-20 2.
List of Recently Issued IE Information Notices 7,
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MAY 8 1980 Georgia Power Company.
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M. Manry, Plant Manager Post Office Box 442 Baxley, Georgia 31513 C. E. Belflower Site QA Supervisor Post Office Box 442 Baxley, Georgia 31513 K. M. Gillespie Construction Project Manager Post Office Box 282 Waynesboro, Georgia 30830 E. D. Groover QA Site Supervisor Post Office Box 282 Waynesboro, Georgia 30830 W. A. Widner, General Manager Nuclear Generation Georgia Po.er Cempany Post Office Box 4545 Atlanta, Georgia 30303 e
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SSINS No.: 6870 UNITED STATES Accession No.:
o NUCLEAR REGULATORY COMMISSION 8002280671 0FFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D. C. 20555 May 8, 1980 IE Information Notice 80-20
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I0S'S 0F DEC Y~ HEAF REMdVCChPXBILITY A'T DAVIS;BESSE'JNIT 1 WHILE IN A REFUELING MODE Description of Circumstances:
On April 19, 1980, decay heat removal capability was lost at Davis-Besse Unit I for approximately two and one-half hours. At the time of the event, the unit was in a refueling mode (e.g., RCS temperature was 90F; decay heat was being removed by Decay Heat Loop No. 2; the vessel head was detensioned with bolts in place,; the reactor coolant level was slightly below the vessel haad flanges; and the manway covers on top of the once through steam generators were removed).
(See Enclosure A, Status of Davis-Besse 1 Prior to Loss of Power to Busses E-2 and F-2 for additional details regarding this event.)
Since the plant was in a refueling mode, many systems or components were out of service for maintenance or testing purposes.
In addition, other systems and components were deactivated to pr.eclude their inadvertent actuation while in a refueling mode. Systems and components that were not in service or deactivated included:
Containment Spray System; High Pressure Injection System; Source Range Channel 2; Decay Heat Loop No. 1; Station Battery IP and IN; Emergency Diesel-Generator No. 1; 4.16 KV Essential Switchgear Bus C1; and 13.8 KV Switchgear Bus A (this bus was energized but not aligned).
In brief, the event was due to the tripping of a non-safeguards feeder breaker in 13.8 KV Switchgear Bus B. Because of the extensive maintenance and testing activities being conducted at the time, Channels 1 and 3 of i.he Reactor Protec-tion System (RPS) and Safety Features Actuation System (SFAS) were being ener-gized from caly one source, the source emanating from the tripped breaker.
Since the SFAS logic used at Davis-Besse is a two-out-of-four input scheme in which the loss (or actuation) of any two input signals results in the actuation of all four output channels (i.e., Channels 1 and 3, and Channels 2 and 4), the loss of power to Channels 1 and 3 bistabletalan esti.1terLhactivademnLSras,.ym Channels 2 and 4.
The actuation of SI:'M"%
^M Decay Heat Loop No. 2, the operating 5
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' 9% ME RM DUPLICATE DOCUMENT Since the initiating event was a loss 1
were actuated (i.e., Level 1 - High R j Entire document previously 1
tion; Level 3 - Low Pressure Injectio entered into system under:
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