ML19256B426
| ML19256B426 | |
| Person / Time | |
|---|---|
| Site: | Marble Hill |
| Issue date: | 06/28/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Coughlin J PSI ENERGY, INC. A/K/A PUBLIC SERVICE CO. OF INDIANA |
| References | |
| NUDOCS 7907100525 | |
| Download: ML19256B426 (1) | |
Text
- "" %'o tic UNITED STATES
! '),,, cf(','n NUCLEAR REGUL, ATORY COMMISSION
$.h'W//.%,' ((f 799 ROOSEVELT ROAD
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REGION 111 g
IIh e
- 3 GLEN ELLYN, ILLINOIS 60137 JUN 2 81979 Dochet No. 50-546 Docket No. 50-547 c..
Public Service of Indiana ATTN:
Dr. James Coughlin Vice President, Nuclear 1000 East Main Street Plainfield, IN 46168 Gentlemen:
The enclosed IE Circular No. 79-12, is forwarded to you for infor-mation.
No written response is reqvired. Should you have any questions related to your understanding of this matter, p ease contact this office.
Sincerely, h
n 0= -
JamesG.heppfer Director
Enclosure:
IE Circular No. 79-12 cc w/ encl:
Mr. R. M. Brown, Construction Project Superintendent Central Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC LeBoeuf, Lamb, Leiby & MacRae
.4 t
7907100515
U.S. NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT REGION III r-C' - -
June 28, 1979 IE Circular No. 79-12 (7906210065)
POTENTIAL DIESEL GENERATOR TURBOCHARGER PROBLEM Description of Circumstances:
The Electro-Motive Division (EMD) of General Motors Corporation has recently identified a potential failure mode of turbochargers used on EMD diesels in nuclear plant standby service.
When an engine is in the normal standby mode, the lubricating oil temperature is maintained at about 115 degrees F and the circulating oil pump supplies warm oil to the turbocharger bearings at a flow rate of about 2 gpm.
Since the total oil pump flow rate is 6 gpm, 4 gpm is also circulated, via a 30 psi relief valve, through the lube oil filter and cooler which serves to keep the entire accessory lubricating oil system primed to support a fast start.
If a power outage occurs, the oil circulating pu=p may stop 5 to 10 seconds before the engine receives a start signal; but the main bearing and piston cooling pump will temediately receive oil from the primed lube oil filter-cooler system thus providing a rapid buildup of engine lube of) pressure throughout the engine bearing sr.d turbocharger systems.
A potential problem occurs, however, if the diesel engine receives a repeat rapid start within a minimus 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 shutdown. Under these circumstances, the full 6 gpm output of the circu-lating pump will flow only to the turbocharger bearings because of the lower viscosity of the hot lubricant. At this temperature, the circulating pump pres 3ure will not reach 30 psi. Until the lube oil cools to about 160 degrees J. no oil will 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 will drain back to the engine sump via the lube oil scavenging pump, and some of the oil from the strainer box will be drawn into the cooler by the system vacuum that develops.
The result is that when a repeat fast start occurs a
time frame after a hot shutdown, lack of engine damage.
In the worst case of a r DUPLICATE DOCUMENT 4
AC actually reach operating speed, 900 RPM, O
'k#
established at the turbocharger thrust b Entire document previously entered of the bearing metal so that cumulative into system under:
vould result in a turbocharger failure.
b ANO No. of pages:
I
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