ML19225A113
| ML19225A113 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 06/28/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Mary Johnson SOUTH CAROLINA ELECTRIC & GAS CO. |
| References | |
| NUDOCS 7907180440 | |
| Download: ML19225A113 (2) | |
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'c UNITED ST ATES NUCL E AR REGULATORY COMMISSION
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JUN 2 81979 In Reply Refer To:
RII:JP0 50-395 South Carolina Electric and Gas Company Attn:
M. C. Johnson, Vice President Special Services and Purchasing Post Office Box 764 Columbia, South Carolina 29218 Gentlemen:
The enclosed IE Circular No. 79-12, is forwarded to 'ou for inforcaticr..
No written response is required.
Should you have any questions related this office.
to your understanding of this natter, please contact Sincerely,
_ i-Jane-P. O'Reilly Director
Enclosures:
1.
IE Circular so. 79-12 2.
List of IE Circulars 1ssued in Last 11 Months 347 013 70 0718 0 t///g
!ga arco UNITED ST ATES
'o, NUCLEAR REGULATORY COMMISSION 8'
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JU f, P t, ' J' In Reply Refer To:
RIl:JP0 S>uth Carolina Electric and Gas Company Attn:
T. C. Nichols, Jr., Vice President Power Production and Syste= Operations Post Office Box 764 Columbia, South Carolina 29218 Gentlemen:
The enclosed IE Circular 50. 79-12, is forvarded to you for infornation.
So written response is required.
Should you have any questions related this office.
to your understanding of this matter, please contact Sincerely,
~
Janes P. O' Reill:,
Director
Enclosures:
1.
IE Circular No. 79-12 2.
List of IE Circulars Issued in Last 12 Months 347 014
JUN 2 81979 South Carolina Electric and Gas Company cc w/ encl; T. B. Conners, Jr.
Conners, Moore and Corber 1747 Pennsylvania Avenue, N.V.
Washington, D.C.
20006 A. A. Smith Quality Assurance Post Office Box 8 290(5 Jenkinsv111e, South Carolina O. S. Bradham, Manager Nuclear Operations Post Off ce Box 8 29065 Jenkinsville, South Carolina 347 0i5
UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 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 code, the lubricating oil temperature is maintained at about 115 degrees F and ti.e circulating oil pump supplies warm oil to the turbocharger bearings at a flow rate of about 2 g;m.
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 acces sory lubricating oil system primed to support a f ast 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 imediately receive oil irom the primed lube oil filter-cooler system thus providing a rapid buildup of engine lube oil 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 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 f rom a previous run in wiach the engine has reached f ull operating temperature.
If, for example, the engine had been operated for about 1 bour 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 o' the lower viscosity of the bot lubricant.
At this temperature, the circulating pump pressure will not reach 30 psi.
Until the lube oil cools to about 160 degrees F, no oil will be supplied via the relief valve to the equipment rack for the first 2 to 3 bours after engine s h u t d ow.
During this coo ing period some of the oil contained in the cooler and filter will drain back ta the engine suer via the lube oil scavenging pump, and some of the oil fror. the strainer box will be drawn into the cooler by the system vacuum that develops.
The result is that w..en a repeat fast start occurs within tbc above 15 minute to 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> time frame after a bot shutdown, lack of prime oil system pressure can cause engine damage.
In the worst case of a repeat fast start, the engine may actually reach operating speed, 900 RPM, before the required oil pressure is established at tbc turbocharger thrust bearing.
This may cause some secat..g of the bearing metal so that cumulative damage from several in h
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IE Circular No. 79-12 June 28, 1979 Page 2 of 2 EMD is currently developing a modification to improve the lube oil s y s t ec..
It is planned t'uot tuis modification will be available for installation in approximately 6 months.
In the interim, the f ollowing actions a' e recommended for those having EMD diesel engines:
1.
Repeated fast hot starts within a minimum 15 minute to 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> time frame after shutdown should be avoided.
Allow the engine to cool at least 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> after it has been operated in the " loaded" mode, or otherwise a restart should be performed within 15 minutes of shutdown.
2.
After changing oil filter elements or dra aang the accessory oil system for any reason and upon refilling of the system make sure that the circu-lating oil pump is in operatiot for at least 30 minutes and that the strainer box is full before starting engine.
The engine sb ald then be brought t3 an idling condition to assure cc.plete filling of accessories before any subsequent fast start is made.
3.
Any small leak at the top of the oil cooler should be corrected.
A leak at this location allows air to be drawn into the cooler during shutdown, which will cause the drain back to be more rapid.
4.
Avoid testing of the redundant diesel engines concurrently.
Where it is necessary to run the redundant diesels concurrently, maintain one diesel in the running mode for a minimum of 3 nours following the shutdown of the other.
No written response to this Circular is required.
If you require additional inf ormation rega rding this subj ect, contact the Director of the appropriate h'RC Regional Office.
347 017
IE Circular No. 79-12 Enclosure June 28, 1979 Page 1 of 3 LISTING OF IE CIRCULARS ISSUED IN LAST TWELVE MONTHS Circular Subject Date Issued To No.
of Issue 78-12 HPCI Turbine Control 6/30/78 All Holders of Valve Lift Rod Bending BWR OLs or cps for plants with HPCI Terry lurblue 78-13 Inoperability of Multiple 7/10/78 All Holders of Service Water Pumps Reactor OLs and cps except for plants located in: AL, AK, CA, FL, GA, LA, MS, SC 78-14 HPCI Turbine Reversing 7/12/78 All Holders of 3kR Chamber Hold Down Bolting OLs or cps for plants with a RFC1 Terry Turbine excepting Duane Arnold and Monticello 78-15 Checkvalves Fail to 7/20/78 All Holders of Close In Vertical Reactor OLs or cps Position 78-16 Limitorque Valve 7/26/78 All Holders of Actuators Reactor OLs or cps 78-:7 Inadequate Guard Training /
10/13/78 All Holders of Qualification and Falsified and applicants Training Records for Reactor OLs 7^-18 UL Fire Test 11/6/78 All Holders of Reactor OLs or cps 78-19 Hanual Override (Bypass) 12/28/78 All Holders of of Safety Actuation Signals cps 347 018
IE Circular No. 79-12 Enclosure June 28,1979 Page 2 of 3 LISTING OF IE CIRCULARS ISSL'ED IN LAST TWELVE MONTHS Circular Subject Date of Issued to No.
Issue 79-01 Administration of 1/12/79 All Holders of Unauthorized Byproduct Licensees except Material to Humans Teletberapy Medical Licensees and each Ra d i opha rma ce ut i c a l Suppliers 79-02 Failure of 120 Volt Vital 2/16/79 All Holders of AC Power Supplies Reactor OLs and cps 79-03 Inadequate Guard Training-2/23/79 All Holders of Qualification and Falsified and applicants Training Records for Special Nuclear Material Licenses in Safeguards Group I 79-04 Loose Locking Nut On 3/16/79 All Holders of Limitorque Valve Reactor OLs or cps Operators 79-05 Motsture Leakage In 3/20/79 All Holders of Stranded Wire Conductors Reactor Ots or cps 79-06 Failure to Use Syringe 4/19/79 All Holders of and Battle Shields in Medical Licensees Nuclear Medicine except teletherapy licensees 79-07 Unexpected Speed Increase 5/2/79 All Holders of of Reactor Rec:rculation BVR OL's or CP's MG Set Resulted in Reactor Power Increase 79-08 Attempted Extortion - Low 5/18/79 All Fuel Facilities Enriched Uranium Licensed by KkJ 79-09 Occurrences of Split or 6/22/79 All Materials Punctured Regulator Diaphrages Priority I, Fuel In Certain Self Contained Cycle and Operating Breathing Apparatus Reactor Licensees 347 019
L IE Circular No. 79-12 Enclosure June 28,1979 Page 3 of 3 LISTING OF IE CIRCULARS ISSUED IN LAST TWELVE MONTHS Circular Subject Date of Issued to No.
Issued 79-10 Pipefittings Manufactured 6/26/79 All Power Reactor from Unacceptable Material Licensees with a CP and/or OL 79-11 Design / Construction 6/27/79 All Applicants Interface Problem for, and Holders of Powei Reactor cps Jk/
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