ML19225A103
| ML19225A103 | |
| Person / Time | |
|---|---|
| Site: | Bailly |
| Issue date: | 06/28/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Shorb E NORTHERN INDIANA PUBLIC SERVICE CO. |
| References | |
| NUDOCS 7907180420 | |
| Download: ML19225A103 (1) | |
Text
- pn nec,#'o u
UNITED STATES 8 'j'., 7 j
NUCL:
"!EGULATORY COMMISSION g/'
~ '. c REGION til o'
799 ROOSEVELT ROAD N
GLEN ELLYP' ILLINOls 60137
%, ' N./
o Docket No. 50-367 M 20 N G.
Northern Indiana Public Service Company ATTN:
Mr. Eugene M. Shorb Senior Vice President 5265 Hohman Avenue Hammond, IN 46325 Gentlemen:
The enclosed IE Circular 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, fa,mes G. & AKeppEer %
(% _ ~ > %
Director
Enclosure:
IE Circular No. 79-12 cc w/ encl:
Central Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC Mr. Dean Hansell, Office of Assistant Attorney General 7907180420 322 00~
U.S. NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT REGION III r--
G-June 23, 1P9 IE Circular No. 79-12 (7906210065)
P9TENTIAL DIESEL GLLERATOR 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 nor=al standby mode, the lubricating oil temperature is maintained at about 115 degrees F and the circulating oil pump supplies warm oil to tne turbocharge-. bearings at a flow rate of about 2 stpm.
Since the total oil pu=p flo:: rate is 6 gp=, 4 gpm is also circulated, via a 30 psi relief valva, 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 a 10 seconds before the engine receives a start signal; but the main bearing and piston cooling pump will i==ediately receive oil from the primed lube oil filter-cooler system thus providing a rapid buildup of engine lube all pressure throughout the engine bearing and turbocharger systems.
A potential problem occurs, however, if the diesel engine receives a repeat rapid start within a minimum of 15 minutes and a maxi =um 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 exa=ple, the engine had been operated for about I hour at full load, the lube oil te=perature would be at about 200 degrees F at time of shutdevn. 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 pump pressure vill not reach 30 psi. Until the lube oil cools to about 160 degrees I, 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 will drain back to the engine su=p via the lube oil scavenging pu=p, and some of the oil from the strainer box vill be drawn into the cooler by the system vacuu= that develops. The result is that when a repeat fast start occursE time frame after a hot shutdown, lack d DUPLICATE DOCUMENT engine damage.
In the worst case of a actually reach operating speed, 900 RFh Entire document previously entercd established at the turbocharger thrust 5 into system under-I of the bearing =etal so that cu=ulativc would result in a turbocharger failure.
ANO hh No. of pages:
e e
d' i
e :-
r
.