ML19296A457
| ML19296A457 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 03/21/1979 |
| From: | Murray T TOLEDO EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| L79-190, NUDOCS 7903270283 | |
| Download: ML19296A457 (2) | |
Text
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r TOLEDO a EDISON L79-190 March 21, 1979 FILE: RR 2 (NP-33-77-56)
Docket No. 50-346 License No. NPF-3 Mr. James C. Keppler Regional Directer, Region III Office of Inspection and Enforcement U. S. Nuclear Regulatory Cocmission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Dear Mr. Keppler:
s for Licensee Enclosed are three copies of the supplemental infonnation sheet Event Report NP-33-77-56, which has been revised. The revisions are indicated by a "1" in the lef t margin.
Please replace your previous supplemental informa' tion sheet for Licensee Event Repcrt NP-33-77-56 with the attached, revised copy.
Yours truly, WC^^) PWA&ll/ph1 Terry D. Murray Station Superintendent Davis-Besse Nuclear Power Station TDM/SNB/1j k Enclosure cc:
Dr. Ernst Volgenau, Director Office of Inspection and Enforcement Encl:
30 copies LER NP-33-77-56 Mr. William G. Mcdonald, Director Office of Management Inf ormation and Program Control Enc 1:
3 copies LER NP-33-77-56 7003270 AE3 THE TOLEDO EDISON COMPANY EDISON PLAZA 300 MAC! SON AVENUE TOLEDO. CH:0 43S52
TOLEDO EDISON COMPANY DAVIS-BESSE UNIT ONE NUCLEAR POWER STATION SUPPLEMENTAL INFORMATION FOR LER NP-33-77-56 DATE OF EVENT: August 16, 1977 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Diesel Generator #1 was inoperable.
Conditions Prior to Occurrence: The plant was in Mode 2, with Power (MWT) = 0 and Load (MWE) = 0.
Description of Occurrence: At 1715 hours0.0198 days <br />0.476 hours <br />0.00284 weeks <br />6.525575e-4 months <br /> on August 16, 1977, the Davis-Besse Station received notice of a tornado which had touched down in the East Toledo area, and was heading in an easterly direction (toward the Station).
In anticipation of the loss of switchyard capability (of f-site power) in the event of a tornado, Station personnel tested the Emergency Diesel Generators s
at 1730 hours0.02 days <br />0.481 hours <br />0.00286 weeks <br />6.58265e-4 months <br />.
Diesel Generator #2 was started without incident.
Diesel Generator #1, however, would not start manually; it automatically shutdown on overspeed.
The DC field would not flash. The station entered Action Statement (a) of Technical Specifi-cation 3.8.1.1.
The tornado did not materialize in the area of the Station, and the tornado warning was cleared at 1820 hours0.0211 days <br />0.506 hours <br />0.00301 weeks <br />6.9251e-4 months <br /> on August 16, 1977.
Designation of Apoarent Cause of Occurrence: The cause of the event is attributed to component failure in the speed switch for Diesel Generator #1.
Burned resistors and shorted diodes were found in the switch (Model #ESSB-4AT).
It was replaced and returned to the manufacturer, Synchro-Start Products, Inc.,
a division of Knowles Electronics, Inc., for repair.
Analysis of Occurrence: There was no danger to the health and safety of the public or Station personnel. Off-site power was not lost, and Diesel Generator
- 2 was operable and able to handle Station loads if necessary.
Corrective Action: The defective speed switch was replaced, and Diesel Generator #1 returned to service on August 17, 1977 at 0740 hours0.00856 days <br />0.206 hours <br />0.00122 weeks <br />2.8157e-4 months <br />. This removed th Station from Action Statement (a) of Technical Specification 3.8.1.1.
The replacement switch operation has been satisfactory. The failed switch has 1
been refurbished by the vendor and was returned to the station as a spare.
Failure Data: There have been no previous similar occurrences.
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