ML19225A101
| ML19225A101 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 06/28/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Gerstner W ILLINOIS POWER CO. |
| References | |
| NUDOCS 7907180418 | |
| Download: ML19225A101 (1) | |
Text
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GLEN ELLYN, ILLINOls 60137 a...*
Docket No. 50-461 Decket No. 50-462 c..
Illinois Power Company AfTN:
Mr. W. C. Gerstner Executive ' lice President 500 South 27th Street Decatur, IL 62525 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, SMek
_a Jam'sG. rep %r
'e Director
Enclosure:
IE Circular No. 79-12 cc w/ encl:
Central Files Director, NRR/DPM Director, NF.R/ DOR PDR Local PDR NSIC TIC Mr. Dean Hansell, Office of Assistant Attorney General 7907180418
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U.S. NUCLEAR REGULATORY COMMISSIrN OFFICE OF INSPECTION AND ENFORCL:ENT REGION III r..
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June 28, 1979 IE Circular No. 79-12 (7906210065)
POTENTIAL DIESEL GENERATOR TURBOCHARGER PROBLEM Description of Circu= stances:
The Electro-Motive Divisicn (EMD) cf General Motors Corporation has recently identified a potential failure mode of urbochargers 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 cil to the turbocharger bearings at a flow rate of about 2 gpm.
Since the total cil pu=p 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 ril 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 i==ediately receive oil from the primed lube oil filter-cooler systen thus providing a rapid buildup -f engine lube oil pressure throughout the engine bearing and turbocharger utems.
A potential problem occurs, however, if the diesel engine receives a repeat rapid start within s mini =um 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 shutde ; fust a previous run in which the engine has reached full operating te=perature.
If, for example, the engine had becn 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 pu=p will flow only to the turbocharger bearing s because of the lower viscosity of the hot lubricant. At this temperature, the circulating pu=p pressure will not reach 30 psi. Until the lube oil cools to about 160 degrees 7, no eil 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 /> af ter engine shutdown. During this cooling period seme 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 s.rainer box will be drawn into the cooler by the system vacuum t hat develops. The result is that when a repeat fast start occurs within the abcve 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 reach operating speed, 900 RFM, befere the required oil pressure is established at the turbocharger thrust bearing. This may cause some smearing of the bearing metal so that cu=ulative damage from several similar starts would result in a turbocharger failure.
7906210005
II Circular No. 79-12 Juna 28, 1979 EMD is7 currently developing a modification to improve the lube oil system.
It is planned that this modification will be available for installaticn in approximately 6 months.
In the interim, the following actions are recccmended for those having EMD diesel engines:
1.
Repeated fast hot starts within a mini =um 15 mirute 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 *.he system make sure that the circu-lating oil pu=p 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 ninimum 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 appropricte NRC Regional Office.
Enclosure:
List of IE Circulars Issued in Last Twelve Months s
IE Circular No. 79-12 June 28, 1979 LISTING OF IE CIRCULARS ISSUED IN C.
LAST WELVE MONTHS Circular Subject Date Issued To No.
of Issue 78-12 HPCI Turbine Control 6/30/78 All !! ciders of Valve Lift Rod Bending BWA OLs or cps for plants with HPCI Terry Turbine 78-13 Inoperability of Multiple 7/10/78 All Holders of Service Water Pu=ps 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 HPCI Terry Turbine excepting Duane Arnold and Monticello 78-15 Checkvalves Fail to 7/20/78 All Holders of Clote In Vertical Reactor OLs or cps Position 78-16 ti=itarque Valve 7/2C/78 All Holders of 4 tu,cors Reactor OLs or cps 78-17 Inadaquate Guard Training /
10/13/78 All Holders of Qtalification and Falsified and applicants Training Records for Reactor OLs 78-18 UL Fire Tes:
11/6/78 All Holders of Reactor OLs or cps 78-19 Manual Override (Bypass}
12/28/78 All Holders of of Safety Actuation Signals cps Enclosure Page 1 of 3 7qt bI
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IE Circular No. 79-12 June 28, 1979 LISTING OF IE CIRCULARS ISSUED IN LAST TWELVE MONTHS Circular Subject Date of Issued to No.
r' Issue f--
79-01 Administration of 1/12/79 All Holders of Unauthorized Byproduct Licensees except Material to Hu=ans Teletherapy Medical Licensees and each Radiophar=aceutical Suppliers 79-02 Failure of 120 Volt Vital 2/16/79 All Holder.
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 Linitorque 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 Medicios except teletherapy licensees 79-07 Unexpected Speed Increase 5/2/79 All Holders of of Reactor Recirculation BWR OL's or CP's MG Set Resulted in Reactor Power Increase 79-48 Attempted Extortion - Lov 5/18/79 All Fuel Facilities Enriched Uranium Licensed by NRC 79-09 Occurreness of Split or 6/22/79 Ali Materials Punctured Regulator Diaphrag=s Priority I, Fuel In Certain Self Contained Cycle and Operating arcathing Apparatus Reacter Licensees Enclosure Page 2 of 3 cs') 3 S:3
Circular No. 79-12 June 28, 1979 LISTING OF IE CIRCULARS ISSUED IN LAST TWELVE MONTHS
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Circular Subject Date of Issued to No.
Issued 79-10 Pipefittings Mar.ufactured 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 Power Reactor cps Enclosure Page 3 of 3 321 3515