ML20084D819
| ML20084D819 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 12/02/1970 |
| From: | Hoyt H COMMONWEALTH EDISON CO. |
| To: | Morris P US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| 04655, 4655, NUDOCS 8304120438 | |
| Download: ML20084D819 (2) | |
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'Commonweahh Edison Company 71 WEST ADAMS S T f1 E E T
- CHICAGO. ILLINOIS Addr.as feely fe-POST OFFICE 50X F47
- C H I C A G O. ILLINOIS 40490
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Dresden Nuclear Power Station',
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a December 2, 1970
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ut. Jeter A. Morris, Director h
Division of Reactor Licensing U.S. Atomic Energy Commission Jashington, D.C.
20545 SulklECT: LICENSE DDR-19 DRESDEN NUCl. EAR P0.;E3 STATION ICIT J2, SECTION n.6.C.1 0F THE TECHNICAL SPECIFICATIONS
Dear Dr. Morris:
This is to report a condition relating to the operation of the station whea during routine surveillance 12 Standby Diesel Generator failed to start follouing a manual initiation signal.
Problem, Investination and Corrective Action Oa November 2, 1970, while conducting routine surveillance on the Unit 2 Diesel Generator, the diesel failed to start following a manual start signal.
Investigation revealed that the pinion gear on the lower starting air motor had failed to engage the engine ring gear, tlius preventing the normal start sequence of the diesel starting air motors.
The probable cause for the failure was an accumulation of oil and scale found beneaLh the seat of the starting air solenoid valve, which prevented proper engage-ment of the starting air motor pinion gear.
Tue starting air solenoid valve was disassembled, cleaned and returned to service and the lower pinica gear was repositioned to allow proper engagement with the engine ring gear.
The diesel was then returned to service and successfully restarted three times to verify its operability.
During the period the Unit J2 diesel was unavailable, the Unit 2/3 diesel was started and loaded to prove its operability in accordance with Section 3.9.B.2 of the Technical Specifications.
The total time that Unit 12 diesel was unavailable was less than 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
The bendix drive and solenoid will be inspected in the near future _on both the Unit 2 and 2/3 diesels.
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Dr. Peter A. Morris Page 2 December 2, 1970 The failure of the solenoid valve to seat maintained a cotistaat pressure against the lower pinion gear and combined with previous running of the engine had also wora some of the bevel off the pinion gear.
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H. K. Hoyt
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Superintendent IIKh:Jme
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