ML19225A105
| ML19225A105 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 06/28/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Clayton F ALABAMA POWER CO. |
| References | |
| NUDOCS 7907180426 | |
| Download: ML19225A105 (2) | |
Text
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JUN 2 81979 In Reply Refer To:
RII:JPO 50-348 50-364 Alabama Power Company Attn:
F. L. Clayton, Jr.
Executive Vice President Post Office Box 2641 Birmingham, Alabaca 35291 Gentlemen:
The enclosed IE Circular 50. 79-12, is forwarded to you for infornation.
So written response is required. Should you have any questions related this office.
to your understanding of this ratter, please contact Sincerely, m ~
5 -
James P-C ' Re ill:.
Director
Enclosures:
1.
IE Circular 50. 79-12 2.
List of IE Circulars Issued in Las: 12 Months
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e JUN 2 8197S Alabama Power Company
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A. F. Barton Executive Vice President Post Office Box 2641 Birmingham, Alabama 35291 J. T. Young Vice President-Production Post Office Box 2641 Birmingham, Alabama 35291 C. Biddinger, Jr.
Manager-Corporate Quality Assurance Post Office Box 2641 Birmingham, Alabama 35291 H. O. Thrash Manager-Nuclear Generation Post Office Box 2641 Bi rmingham, Alabama 35291 H. G. Hairston, III Plant Manager Drawer 470 Ashford, Alabama 36312 R. E. Hollands, Jr.
QA Supervisor Post Office Box U Ashford, Alabama 36312 b
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UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 June 28, 1979 IE Circular No. 79-12 (7906210065)
POTENTI AL DIESEL GENERATOR TURBOCHARGER PROBLEM Dercription of Circumstances:
TF Electrn-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.
Vnen 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 ware 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 ci rculated, via a 30 psi relief valve, through the lube oil filter and cooler which ecves to keep the entire accessory lubricating oil system primed to support a fast start.
If a power outage occurs, the oil circulating pump may stop 5 to 10 seconds before the ergine receives a start signal; but the main bearing and piston cooling pump will immediately receive oil from the primed lube oil filter-cooler system thus providing a rapid buildup of engine lobe oil pressure throughout the engine bearing and turbocharger systems.
A potential problem occurs, however, if the diesel engine receives a repeat rapid st art 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 /> af ter a shutdown from a previous run in which the engine has reached full operating temp e ra t u re.
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 bot lubricant.
At this temperature, the circulating pts; 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 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 s um; via the lube oil scavenging pump, and some of the oil f rom 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 within the 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 hot shutdown, lack of prime oil systew 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 the turbocharger thrust bearing.
This may cause some smearing of the bearing metal so that cumulative damage from several similar starts would result in a turbocharger failure.
322 0i4
s lE Circular No. 79-12 June 28, 1979 Page 2 of 2 EMD is currently developing a modi.ication to improve the lube oil system.
It is planned that this modification will be available for installation in approximately 6 months.
In the interim, the following actions are recommended for those having EKD diesel engines:
1.
Repeated fast hot.t r -t s witnin a minimum lE ninute 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 draining the accessory oil system far any reason, and upon refilling of the system make sure that the circu-lating oil pump is in operation for at least 30 minutes and that the strainer box is full before starting engine.
The engine should then be brought to an idling condition to assure complete 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 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> following the shutdown of the other.
No written resp nse to this Circular is required.
If you require additional inf ormation regarding ' his subject, contact the Director of the appropriate NRC Regional Office.
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IE Circular No. 79-12 Enclosure June 28, 1979 Page 1 of 3 LISTING OF IE CIRCULAR $ 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 Turbine 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 BWR Chamber Hold Down Bolting OLs or cps fr -
plants with a HPCl Terry Turbine excepting Duane Arnold and Monticello 73-15 Checkvalves Fall to 7/20/78 All Holders of Close In Vertical Reactor OLs or cps Position 78-16 Limitorque Valve 7/26/78 All Holde-s of Actuators Reactor OLs or cps 78-17 Inadequate Guard Training /
10/13/78 All Holders of Qualification and Falsified and applicants Training Records for Reactor OLs 78-18 UL Fire Test 11/6/78 All Holders of Reactor OLs or cps 78-19 M nual Override (Bypass) 12/28/78 All Holders of of Safety Actuation Signals cps
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IE Circular No. 79-12 Enclosure June 28, 1979 Page 2 of 3 LISTING OF IE CIRCULARS ISS'JED 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 Teletherapy Medical Licensees and each Radi opba rma ceut i c a l Suppliers 79-02 Failure of 120 Volt Vital 2/16/79 All Holders f
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 Lockin; Nut On 3/16/79 All Holders of Limitorque Vas ve Reictor OLs or cps Operators 79-05 Motsture Leakage In 3/20/79 All Holders of Stranded Wire Conductors Reactor OL< or cps 79-06 Failure to Use Syringe 4/19/79 All Holders of and Battle Shields in Medical Licensees Nuclear Medicine excer* teletherapy licensees 79-07 Unexpected Speed Increase 5/2/79 All Holders of of Reactor Recirculation 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 NRC 79-09 Occurrences of Split or 6/22/79 All Materials Punctured Regulator Diaphragms Priority I, Fuel In Certain Self Contained Cycle and Operating Breathing Apparatus Reactor Licensees j
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IE Circular No. 79-12 Enclosure June 28, 1979 Pege 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 Mat (rial Licensees with a CP and/or OL 79-11 Design /Censtruction 6/27/79 All Applicants Interface Problem for, and Holders of Power Reactor cps
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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 Gene al Motors Corporation has recently identified a potential failure nude 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 lubric ting oil system primed to support a fast start.
If a power outage occurs, the oil circulating pump may stop 5 to 10 seconds * ? fore the engine receives a start signal; but the main bearing and piston cooling pump will 0eediately receive oil from the primed lube oil filter-cooler 2
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 from a previous run in which the engine has reached full 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 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 F, eo oil will be supplied via the relief valve to the equipment rack for tic 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 surp via the lube oil scavenging pump, and some of the oil f rom the st rainer box will be drawn into the cooler by the system vacuum that develops.
The result is that when a repeat fast start occurs within the 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 af ter a hot shutdown, lack of prime oil system pressure can cause engine damage.
In the worst c.sse of a repeat
..c start, the engine may actually reach operating speed, 900 RPM, before the required oil pressure is established at the turbocharger thrust bearing.
This may cause some smearing of the bearing metal so that cumulative damage from several similar starts would result in a turbocharger failure.
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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 system.
It is plann' ! that this modification will be available for installation in approximate f 6 months.
In the interim, the following actions are 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 /> tim'. frame after shutdown should be avoided.
Allow the engine to cool at least hours after it has been operated in the " loaded" mode, or otherwise a restart should be performed within 15 minutes of shutdown.
2.
Af ter changing oil filter elements or drain.ng the accessory oil system f or i
any reason, and upon refilling of the system make sure that the circu-lating oil pump is it operation for at least 30 minutes and that the strainer box is full before starting engine.
The engine should then be brought to an idling condition to assure complete 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 tc be drawn into the cooler during shutdown, which will cause the drain ba r 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 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> following the shutdown cf the other.
No written response to this Circular is required.
If you require additional information rega rding this subject, contact the Director of the appropriate NRC Regional Office a9 r '. r.
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IE Circular No. 79-12 Enclesure June 28, 1979 Page 1 of 3 LISTING OF IE CIRCULARS ISSL'ED 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 Turbine 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 BWR Chamber Hold Down Bolting OLs or cps for plants with a EPCI 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 78-17 Inadequate Guard Training /
10/13/78 All Holders of Qualification and Falsified and applicants Training Records for Reactor OLs 78-18 UL Fire Test 11/6/78 All Holders of Reactor OLs or cps 78-19 Manual Override (Bypass) 12/28/78 All Halders of of Safety Actuation Signals Clw 322 02',
1 IE Circular No. 79-12 Enclosure June 28, 1979 Page 2 of 3 LISTING OF IE CIRCULARS ISSUED IN LAS1 TVELVE 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 Teletherapy Medical Licensees and e 2ch Radiopharmaceutical 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 applic.nts Training Records for Special Nuclear Material Licenses in Safeguards Group 1 79-04 Loose Locking Nut On 3/16/79 All Holders of Limitorque Valve Reactor OLs or cps Operators 79-05 Moisture Leakage In 3/20/79 All Holders of Stranded Wire Conductors Reactor OLs 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 Rectreulation BWR 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 NRC 79-09 Occurrences of Split or 6/22/79 All Materials Punctured Regulator Diaphragms Priority I, Fuel In Certain Self Contained Cycle and Operating Breathing Apparatus Reactor Licensees 322 0:2
IE Circular No. 79-12 Enclosure June 28, 1979 Page 3 of 3 LISTING OF IE CIRCULARS ISSUED IN LAST TVEIXE MONTHS Circular Subject Date of Issued to No.
Issued 79-10 Pipef2ttings Manufactured 6/26/79 All Power Reactor f rom Unacceptable Material Licensees with a CP and/or OL 79-11 Design / Construction 6/27/79 All Applicants Interface Proble-for, and Holders of Power Reactor cps Tq7 n ", '
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