ML19246B737
| ML19246B737 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point, Palisades File:Consumers Energy icon.png |
| Issue date: | 06/28/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Dewitt R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| References | |
| NUDOCS 7907180406 | |
| Download: ML19246B737 (1) | |
Text
pa arc o q'o, UNITED STATES
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NUCLEAR REGULATORY COMMISSION PDR.
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REGION lll
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e GLEN ELLYN, ILLINOls 60137
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Jtm 2 81979 Docket No. 50-155 Doc.ket No. 50-255 c.
Consumers Power Company ATTN:
Mr. R. B. DeWitt Manager of Nuclear Plant Operations 212 West Michigan Avenue Jackson, MI 49201 Gentlemen:
The enclosed IE ctreular No. 79-12, is forwarded to you for infor-mation. No written response is required. Should you have any questions related to your understanding of this matter, please contact this office.
Sincerely, C% m b gn ~ O' NamesG.KeMer_-
Director
Enclosure:
IE Circular No. 79-12 cc w/ encl:
Mr. C. J. Hartman, Plant Superintendent Mr. i. G. Lewis, Plant Superintendent Central Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC Ronald Callen, Michigan Public Service Commission Anthony Roisman, Esq., Attorney Myron M. Cherry, Chicago
_s 79 0718 d 4 0 6 364 203
U.S. NUCLEAR REGULATORY CCMMISSION OFFICE OF INSPECTION AND ENFORCEMENT REGION III e_
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June 28, 1979 IE Circular No. 79-12 (7906210065)
POTENTIAL DIESEL GENERATOR TURBOCHARGER PROBLEM Description of Circumstances:
The Electro-Motive Division (EMD) c' 'anral Motors Corporation has recently identified a potential failure mode
.f turbochargers used on EMD diesels in nuclear plant standby service.
When an engine is in the nor=al staidby mode, the lubricating cil temperature is maintained at about 115 degrees'? and the circulating oil pump supplies varm oil to the turbocharger bearings at a flow rate of about 2 gpm.
Since the total oil pump flow rate is o gpm, A gpm is also circulsted, via a 30 psi i
relief valve, through the lube oil filter and cooler which ssrves to keep the entire accessory lubricating nil system primed to support a fast start.
If a power outage occurs, the oil circulating pu=p may stop 5 to 10 seconds before i
the engine receives a start signal; but the =ain bearing and piston cooling pu=p will i= mediately receive oil from the primed lube oil filter-cooler system thus providing a rapid buildup of engine lube oil pressure throughout i
the engine bearing and turbocharger syste=s.
A potential problem occurs, however, if the diesel engine receives a repeat rapid start within a minimum of 15 minutes and a maximum of 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> after a shutdown from a previous run in which the engine has reached full operating temperature.
If, for example, the engine had been operated for about I hour at full load, the lube oil temperature would be at about 200 degrees F at time of siutdown. Under these circumstances, the full 6 gpm output of the circu-lating pu=p will flow only to the turbocharger bearings because of the lower viscosity of the hot lubricant. At this temperature, the circulating pu=p pressure vill not reach 30 psi. Until the lube oil cools to about 160 degrees
- 7. no oil vill be supplied via the relief valve to the equipment rack for the first 2 to 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> after engine shutdown. During this cooling period some of the oil contained in the cooler and filter vill drain back to the engine sump via the lube oil scavenging pump, an8 nme of the oil from the strainer box vill be drawn into the cooler by the g -
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~ _, N 1 A result is that when a repeat fast start occ time frame af ter a hot shutdown, lac pUPLICATE DOCUMENI engine damage. In the worst case o:
Enti actually reach operating speed, 900 into sy te nt previously entered established at the turbocharger thr n er:
of the bearing metal so that cumula
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ANO would result in a turbocharger fail No. of pages:
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