ML18116A145
| ML18116A145 | |
| Person / Time | |
|---|---|
| Site: | Surry, North Anna  |
| Issue date: | 06/28/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Proffitt W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| References | |
| NUDOCS 7907180446 | |
| Download: ML18116A145 (7) | |
Text
-.Q e
e UNITED STATES NUCLEAR REGULATORY COMMISSION REGION II 101 MARIETTA ST., N.W., SUITE 3100 ATLANTA, GEORGIA 30303 JYN 2 81979 In Reply Refer To:
RII:JPO 50-338, 50-339 c::;o-404 50-405 p-2ao: 5o-i.si=1' Virginia Electric and Power Company Attn:
W. L. Proffitt Senior Vice President, Power P.O. Box 26666 Richmond, Virginia Gentlemen:
23261 The enclosed IE Circular No. 79-12, is forwarded to you for information.
No written response is required.
Should you have any questions related to your understanding of this matter, please contact this office.
Enclosures:
- 1.
IE Circular ~o. 79-12
- 2.
List of IE Circulars Issued in Last 12 Months i1.
Sincerely, James P. O'Reilly Director
Virginia Electric aud Power Coepany e
cc v/encl:
W. l. Cartwright, Station Maoaaer Poat Office Bos 402 Mineral, Vir1inia 13117 P. G. Perry Senior Resident En1ineer Post Office Bos 38 "ineral, Vir1inia 23117 W. L. Stewart, Manager Post Office Box 315 Surry, Vir&inia 23883 e
JUN 2 8 1979 e
e UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 June 28, 1979 POTENTIAL DIESEL GENERATOR TURBOCHARGER PROBLEM Description of Circumstances:
IE Circular No. 79-12 (7906210065)
The Electro-Motive Division (EHD) of General Motors Corporation has recently identified a potential failure mode of turbochargers used on EHD 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 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 i111nediately 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 bas reached full operating temperature.
If, for example, the engine had been operated for about l hour at full load, the lube oil temperature would be at about 200 degrees Fat time of shutdown.
Under these circumstances, the full _6 gpm output of the circu-lating pump will flo"'* only to the turbocharger bearings because of the lower viscosity of the bot lubricant.
At this temperature, tbe 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 shutdO\\o'Tl.
During this cooling pt-nod some of the oil contained in the cooler and f1ltt-r will drain back to the engine sumr via the lube oil,cavenging pump, and some of the oil from the strainer box will be drawn into tht-coolt-r by the system vacuum that develops.
The result i1 that when a rept-al fast start occurs within the above 15 ainute to 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> ti~ frame after a hot shutdown, lack of primt-oil system pressure can cause engine damage.
Jn the worst case of a repeat fast start, the engine may 1ctu1lly reach operating speed, 900 RPH, before the required oil pressure is e1t1bli,hed 1t the turbocharger thrust bearing.
This may cause 1oae sllt'aring of the bearing ~t*l so that cuaul1tive d1magt-froe several 1iail1r starts vould result in I turbocharger failure.
I l
e IE Circular No. 79-12 e
June 28, 1979 Page 2 of 2 El'ID is currently developing 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 recouunended for those having El1D diesel engines:
- l.
Repeated fast hot starts within a m1n1mum 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 othen,;ise 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 shutdo.'Il, 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.
e IE Circular No. 79-12 June 28, 1979 Circular No.
78-12 78-13 78-14 78-15 78-16 78-17 78-18 78-19 LISTING OF IE CIRCULARS ISSUED IN LAST TWELVE MONTHS Subject HPCI Turbine Control Valve Lift Rod Bending Inoperability of Multiple Service Water Pumps HPCI Turbine Reversing Chamber Hold Down Bolting Checkvalves Fail to Close In Vertical Position Limitorque Valve Actuators Inadequate Guard Training/
Qualification and Falsified Training Records UL Fire Test Hanual Overrid~ (Bypass) of Safety Actuation Signals Date of Issue 6/30/78 7 /10/78 7 /12/78 7/20/78 7 /26/78 10/13/78 11 /6/78 12/28/78 e
Enclosure Page 1 of 3 Issued To All Holders of BWR OLs or CPs for plants with HPCI Terry Turbine All Holders of Reactor OLs and CPs except for plants located in: AL, AK, CA, FL, GA, LA, HS, SC All Holders of BWR OLs or CPs for plants with a HPCI Terry Turbine excepting Duane Arnold and Monticello All Holders of Reactor OLs or CPs All Holders of Reactor OLs or CPs All Holders of and applicants for Reactor OLs All Holders of Reactor Ols or All Holders of CPs CPs
IE Circular No. 79-12 June 28, 1979 Circular No.
79-01 79-02 79-03*
79-04 79-05 79-06 79-07 79-08 79-09 LISTING OF IE CIRCULARS ISSUED IN LAST TWELVE MONTHS Subject Administration of Unauthorized Byproduct Material.to Humans Failure of 120 Volt Vital AC Power Supplies Inadequate Guard Training-Qualification and Falsified Training Records Loose Locking Nut On Limitorque Valve Operators Moisture Leakage In Stranded Wire Conductors Failure to Use Syringe and Battle Shields 1n Nuclear Medicine Unexpected Speed Increase of Reactor Recirculation MG Set Resulted in Reactor Power Increase Attempted Extortion - Lo~
Enriched Uranium Occurrences of Split or Punctured Regulator Diaphragms In Certain Self Contained Breathing Apparatus Date of Issue 1/12/79 2/16/79 2/23/79 3/16/79 3/20/79 4/19/79 5/2/79 5/18/79 6/22/79 Enclosure Page 2 of 3 Issued to All Holders of Licensees except Teletberapy Medical Licensees and each Radiopbarmaceutical Suppliers All Holders of Reactor OLs and CPs All Holders of and applicants for Special Nuclear Material Licenses in Safeguards Group I All Holders of Reactor OLs or CPs All Holders of Reactor OLs or CPs All Holders of Medical Licensees except teletberapy licensees All Holders of BWR Ol's or CP's All Fuel Fac1l1t1es Licensed by NRC All Materials Priority I, Fuel Cycle and Operating Reactor Licensees
IE Circular No. 79-12 June 28, 1979 Circular Ho.
79-10 79-11 LISTING OF IE CIRCULARS ISSUED IN LAST TWELVE MONTHS Subject Pipefittings Manufactured from Unacceptable Material Design/Construction Interface Problem Date of Issued 6/26/79 6/27 /79 Enclosure Page 3 of 3 Issued.to All Power Reactor Licensees with a CP and/or OL All Applicants for, and Holders of Power Reactor CPs