ML19312C950
| ML19312C950 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 04/02/1976 |
| From: | DUKE POWER CO. |
| To: | |
| Shared Package | |
| ML19312C942 | List: |
| References | |
| RO-287-76-02, RO-287-76-2, NUDOCS 8001140604 | |
| Download: ML19312C950 (2) | |
Text
-
G Duke Power Company Oconee Unit 3 Report No:
R0-287/76-2 Report Date: April 2, 1976 Occurrence Date: March 3, 1976 Facility: Oconee Unit 3, Seneca, South Carolina i
)
Identification of Occurrence: Standby bus breaker improperly taken out of of service.
]
1 Conditions Prior to Occurrence: Unit 1 at refueling shutdown Unit 2 at 100% full power Unit 3 in startup mode, reactor power approximately 18% full power Description of Occurrence:
On March 3,1976, annual preventative maintenance was performed on the Oconee Nuclear Station 4160 volt switchgear. This work required that one standby bus breaker at a time be removed from service.
The Oconee Units 1 and 2 work was completed and the standby bus breakers returned to service.
Permission was then received to remove Oconee Unit 3 standby bus breaker No. I from service at 1100 hours0.0127 days <br />0.306 hours <br />0.00182 weeks <br />4.1855e-4 months <br />.
On the next shift, at 2245 hours0.026 days <br />0.624 hours <br />0.00371 weeks <br />8.542225e-4 months <br />, the Oconee Unit 3 control operator observed that there was no indication on the control room switch for this breaker.
Investigation revealed that this breaker had been racked out, and no tag or Out of Normal Check Sheet identified the reason for the breaker's being out of service. The breaker was restored to service at 2300 March 3, 1976.
Designation of Apparent Cause of Occurrence:
The apparent cause of this occurrence was inadequate communication between the operations personnel which resulted in an "Out of Normal Check Sheet" i
not being completed for the removal of this breaker from service. Two individuals were under the impression that the other had completed the "Out of Normal Check Sheet" when neither had done so.
The status of the breaker was, therefore, not adequately communicated between shifts.
Analvsis of Occurrence:
Oconee Nuclear Station Technical Specification 3.7.2 permits one of the two redundant standby bus breakers to be removed from service, for test or maintenance, during power operation of the reactor. A time period of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is permitted for this maintenance because of the extremely low probability of a postulated accident and the simultaneous failure of the redundant standby bus breaker.
In this incident, one of the two standby bus breakers was inoperable for a period of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
It is concluded that the health and safety of the public was not affected by this occurrence.
011 80
., R0-287/7622 April.2, 1976 i
~
Page 2 t
Corrective Action:
i This occurrence has been discussed with the personnel involved, and the i
deficiency in their actions identified. All operating personnel will review this incident to prevent its future repetition.
i 4
i e
4 t
i i
i I
'1
-........ - -.