ML19246B791
| ML19246B791 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 06/28/1979 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Herbein J METROPOLITAN EDISON CO. |
| References | |
| NUDOCS 7907180615 | |
| Download: ML19246B791 (1) | |
Text
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'o UNITED STATES I) p, NUCLEAR REGULATORY COMMISSION g
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,e KING OF PRUSSIA, PENNSYLVANIA 19406 June 28, 1979 Docket Nos. 50-289 m 50-320~
Metropolitan Edison Company ATTN:
Mr. J. G. Herbein Vice President P. O. Box 542 Reading, Pennsylvania 19640 Gentle,nen:
The er.:losed IE Circular No. 79-12, is forwarded to you for informaticn.
No written response is required.
Should you have any questions related to your understanding of this matter, please contact this office.
Sincerely,
- / 8h ce H. Grier 1 rector
Enclosures:
1.
IE Circular No. 79-12 2.
List of IE Circulars Issued in Last Twelve Months cc w/encls:
E. G. Wallace, Licensing Manager J. J. Barton, Project Manager L. L. Lawyer, Manager - Generation Operations G. P. Miller, Manager - Generating Station - Nuclear 344 156 J. L. Seelinger, Unit 1 Superintendent W. E. Potts, Unit 1 Superintendent - Technical Support J. B. Logan, Unit 2 Superintendent G. A. Kunder, Unit 2 Superintendent - Technical Support I. R. Finfrock, Jr.
Mr. R. Conrad
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G. F. Trowbridge, Esquire Miss Mary V.:Southard, Chairman, Citizens for a Safe Environment 2
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ENCLOSURE 1 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 IE Circular No. 79-12 Date:. June 28, 1979 Page 1 of 2 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 lobe 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 pump may stop 5 to 10 seconds before the engine 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 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 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> 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 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 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 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 system pressure can cause engine damage.
In the worst case of a repeat fast start, the engine may actually reacti operating speed, 900 RPM, before the required oil pressure i_s.
established at the curbocharger 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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' Enclosure 1 IE Circular No. 79-12 Date:
June 28, 1979 Page 2 of 2 EMD is currently developin0 a modification 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 EMD diesel engines:
1.
Repeated fast hot starts i,ithin 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 draining the accessory oil system for 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 response to this Circular is required.
If you require additional information regarding this subject, contact the Director of the appropriate NRC Regional Office.
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ENCLOSURE 2 IE Circular No. 79-12
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June 28, 1979 Page 1 of 3 LISTING OF IE CIRCULARS ISSUED IN LAST TWELVE MONTHS Circular Subject First Date Issued To No.
of Issue 78-12 HPCI Turbine Control 6/30/73 All Power Reactor Valve Lift Rod Bending Facilities with an Operating License (OL) or Construction Permit (CP) having a HPCI Terry Turbine 78-13 Inoperability of 7/10/78 All Power Reactor Multiple Service Facilities with an Water Pumps OL or CP, except those located in:
AL, AK, CA, FL, GA, LA, MS, SC 78-14 HPCI Turbine Reversing 7/17/78 All Power Reactor Chamber Hold Down Facilities with an Bolting OL or CP having a HPCI Terry Turbire excepting Duane Arnold and Monticello 78-15 Tilting Disk Check 7/24/78 All Power Reactor Valves Fail to Close Facilities with an with Gravity in Vertical OL or CP Position 78-16 Limitorque Valve 7/26/78 All Power Reactor Actuators Facilities with an OL or CP 78-17 Inadequate Guard 10/13/78 All Power Reactor Training / Qualification Facilities with an OL; and Falsified Training Susquehanna 1 & 2, Shoreham, Records and Salem 2
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-Enclosure 2 IE Circular No. 79-12 Date:
June 28, 1979 Page 2 of 3 LISTING OF IE CIRCULARS ISSUED IN LAST TWELVE MONTHS Circular Subject First Date Issued To No.
of Issue 78-18 UL Fire Test 11/6/78 All Power Reactor Facilities with an OL or CP 78-19 Manual Override (Bypass) 12/29/78 All Power Reactor of Safety Systems Facilities with a Actuation Signals CP 79-01 Administration of 1/12/79 All Medical Licensees, Unauthorized Byproduct except Teletherapy Material to Humans Medical Licensees, and all Licensad Radio-pharmaceuth :
Distributors 79-02 Failure of 120 Volt 1/16/79 All Power Reactor Vital AC Power Supplies Facilities with an OL or CP 79-03 Inadequate Guard 2/23/79 All Holders of and Training / Qualification Applicants for and Falsified Training Special Nuclear Records Material Licenses in Safeguards Group I 79-04 Loose Locking Nut on 3/16/79 All Power Reactor Limitorque Valve Facilities with an Operators OL or CP 79-05 Moisture Leakage in 3/20/79 All Power Reactor Stranded Wire Facilities with an Conductors OL or CP J O
IE Circular No. 79-12 Date: June 28, 1979 Page 3 of 3 LISTING OF IE CIRCULARS ISSUED IN LAST TWELVE MONTHS Circular Subject First Date Issued To No.
of Issue 79-06 Failure to Use Syringe 4/19/79 All Holders of and Bottle Shields in Medical Licenses Nuclear Medicine Except Teletherapy Licenses 79-07 Unexpected Speed 5/2/79 All BWR Power Reactor Increase of Reactor Facilities with an Recirculation MG Set OL or CP Resulted in Reactor Power Increase 79-08 Attempted Extortion-5/18/79 All Fuel Facilities low Enriched Uranium and Licensed Reactors 79-09 Occurrences of Split 6/22/79 All Materials Priority or Punctured Regulator I, Fuel Cycle and Diaphragms in Certain Operating Reactor Self-Contained Licensees Breathing Apparatus 79-10 Pipefittings Manu-6/26/79 All Power Reactor factured from Facilities with an Unacceptable Material OL or CP 79-11 Design / Construction 6/27/79 All Applicants for, Interface Problem and Holders of cps
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