ML19210C145
| ML19210C145 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 10/30/1979 |
| From: | Baer R Office of Nuclear Reactor Regulation |
| To: | Crews E SOUTH CAROLINA ELECTRIC & GAS CO. |
| References | |
| NUDOCS 7911130330 | |
| Download: ML19210C145 (10) | |
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UNITED STATES y}
g NUCLEAR REGULATORY COMMISSION
- . C WASHINGTON, D. C. 20555 f
0013 o 1g79
%,e.w..+,5 Docket No. S0-395 Mr. E. H. Crews, Jr.
Vice President and Group Executive Engineering and Construction South Carolina Electric and Gas Company P. O. Box 764 Columbia, Scuth Carolina 29218
Dear Mr. Crews:
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION ON THE FINAL SAFETY ANALYSIS REPORT FOR THE VIRGIL C. SUMMER NUCLEAR STATION The enclosed request for additional information is derived from a report recently completed by the University of Dayton Research Institute for the Nuclear Regula-tory Comission. The report entitled " Enhancement of Onsite Emergency Diesel Generator Reliability" (NUREG/CR-0660), identifies problem areas contributing to the unreliability of emergency diesel generators. We request that you respor.d to all of the items in the Enclosure by December 15, 1979.
If you cannot meet this schedule, please provide us with your schedule within seven days of the receipt of this letter.
Sincerely, h
$c
' '7 Robert L. Baer, Chief Light Water Reactors Branch No. 2 Division of Project Miragement
Enclosure:
RecJest for Additional Information ccs w/ enclosure:
See next pages e
79111303 3 b g
Mr. E. H. Crews, Jr., Vice President and Group Executive - Engineering ET S 0 M and Construction South Carolina Electric & Gas Company P. O. Pox 764 Columbia, South Carolina 29218
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Mr. H. T. Babb General Manager - Nuclear Operations and Systeni Planning South Carolina Electric & Gas Company P. O. Box 764 Colunbia, South Carolina 29218 G. H. Fischer, Esq.
Vice President & Group Executive South Carolina Electric & Gas Company P. O. Box 764 Colunbia, South Carolina 29218 Mr. William C. Mcscher President & Chief Executive Of ficer South Carolina Public Service Authority 223 North Live Oak Drive Moncks Corner, South Carolina 29461 Mr. William A. Williams, Jr.
Vice President South Carolina Public Service Authority 223 North Live Oak Drive Moncks Corner, South Carolina 29461 Wallace S. Murphy, Esq.
General Counsel South Carolina Public Service Authority 223 North Live Oak Drive Moncks Corner, South Carolina 29461 Troy B. Conner, Jr., Esq.
Conner, Moore & Corber 1747 Pennsylvania Avenue, N. W.
Washington, D. C.
20006 Mr. Mark B. Whitaker, Jr.
Manager, Nuclear Licensing South Carolina Electric & Gas Company P. O. Box 764 Colunbia, South Carolina 29218 Mr. 0. W. Dixon Group Manager, Production Engineering 1321 002 South Carolina Electric & Gas Company P. O. Box 764 Columbia, South Carolina 29218
Mr. E. H. Crews, Jr.
OCT301979 cc:
.v.r. Brett Allen Bursey Route 1 Box 93C Little Mountain, South Carolina 29076 Mr. J. Skolds United States Nuclear Regulatory Comission P. O. Box 1047 Irmo, South Carolina 29063 1321 003
ENCLOSURE 00T c 1970
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REQUEST FOR AULTTIONAI INFORMATION 040.37 Experience at some operating plants has shown that diesel engines have (9.5.8) failed to start due to accumulation of dust and other delf terious material on electrical equipment associated with starting of th6 diesel generators (e.g., auxiliary relay contacts, control switch.s - etc.).
Describe the provisions that have been made in your diesel generater building design, electrical starting system, and combustion air and ventilation air intake design (s) to preclude this condition to assure availability of the diesel generator on demand.
Also describe under normal plant operation what procedure (s) will be used to minimize accumulation of dust in the diesel generator room.
In your response also consider the condition when Unit 1 is in operation and other construction is being done in the vicinity of Unit 1.
040.88 Assume an unlikely event has occurred requiring operation of a diesel generater (9. 5. 4) for a prolonged period that would require replenishment of fuel oil without in-terrupting operation of the diesel generator. What provision will be made in the design of the fuel oil storage fill system to minimize the creation of tur-bulence of the sediment in the bottom of the storage tank. Stirring of this sediment during addition of new fuel has the potential of causing the overall quality of the fuel to beccme unacceptable and could potentially lead to the degradation or failure of the diesel generator.
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h 040.09 Provide a detailed discussion (or plan) of the level of training p oposed (8.3) for your operators, raintenance crew, quality assurance, and supervisory personnel risponsible for the operation and raintenance of the emergency diesel generators.
Identify the number and tyse of personnel that will be dedicated to the operctions and maintenance of the emerge.ncy diesel generators and the number and type that will be assigned from your general plant operations and maintenance groups to assist when needed.
In your discussion identify the amount and kind of training that will be received by each of the cbove categories and the type of ongoing training program planned to assure optimum availability of the emergency generators.
Also discuss the level of education and minimum experience requirements for the various categories of operations and raintenance personnel associated with the emergency diesel generators.
340.90 Several fires have occurred at some operating plants in the area of (9.5.7)
RSP the diesel engine exhaust rantfold and ins 'de the turbocharger housing which have resulted in equipment unavaileaflity. The fires were started from lube oil leaking and accuralating on the engine exhaust 1321 005 D
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-L ef fold and accumulating and igniting inside the turbocharger housing.
wumulation of lube oil in these areas, on some engines, is'apparently caused from an excessively long prelube period, generally longer than five minutes, prior to manual starting of a diesel generator. This condition does not occur on an emergency start since the prelube pttriod is minimal.
When manually starting the diesel generators for any reason, to minimize the potential fire hazard and to improve equipnent availability, the prelube period should be limited to a maximum of three to five minutes unless otherwise recomended by the diesel engine manufacturer. Confirm your compliance with this requirement or provide your justification for requiring a longer prelube time interval perior to manual starting of the diesel generators.
Provide the prelube time interval your diesel engine will be exposed to prior to manual start.
040.91 An emergency diesel generator unit in a nuclear power plant is nomally (9.5.7)
RSP in the ready standby =cde unless there is a loss of offsite power, an accident, or the diesel generator is under test. Long periods on standby have a tendency to drain or nearly empty the engine lube oil piping system. On an emergency start of the engine as much as 5 to 14 or wre secolidt may elapse from the strt of cranking until full lube oil pressure is attained even though full engine speed is generally reached in about five seconds. With an essentially dry engine, the comentary lack cf lubrication at the various moving parts may damage bearing surfaces pro-ducing incipient or actual component failure with resultant equipment unavailability.
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. OCT 2 O G9 The emergency condition of readiness requires this equipment to attain full rated speed and enable automatic sequencing of electric. load within ten seconds.
For this reason, and to improve upon the availability of this equipment on demand, it is necessary to establish as quickly as possible an oil film in the wearing parts of the diesel en.g.2 Lubricating oil is nonnally delivered to the engine wearing parts by one or more engine driven pump (s). During the sta-ting cycle the pump (s) accelerates slowly with the engine a'id nay not supply the required quantity of lubricating oil where needed fast enough. To remedy this condition, as a minimum, an electrically driven lubricating oil pump, powered from a reltat'e DC power supply, should be installed in the lube oil system to operate in parallel with the engine driven main lube pump. The electric driven prelube pump should operate only during the engine cranking cycle or until satisfactory lube oil pressure is established in the engint main lube distribution header.
The installation of this prelube pump should be coorcinated with the respective engine manufacturer. Some diesel engines include a lube oil circulating pump as an intregal part of the lube oil preheating system which is in use while the diesel engine is in the standby mode.
In this case an_ additional prelube oil pump may not be needed.
Confirm your complianc3 with the above requirement or provide your justification for not installing an electric prelube oil pump.
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. OCT 3 c 1979
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k 040.92 Periodic testing and test loading of an emergency die:el generator (8.3)
RSP in a nuclear power plant is a necessary function to demonstrate the operability, capability and availability of the unit on demand Periodic testing coupled with good preventive raintenance practices will assure optimum equipment readiness and availability on demand. This is the desired goal.
To achieve this optimum equipment readiness status of the following requirements should be met:
1.
The equipment should be tested with a minimum loadtng of 25 percent of rated load. No load or light load operation will cause incomplete combustion of fuel resulting in the for ation of gum and varnish deposits on the cylinder walls, intake and exhaust valves, pistons and piston rings, etc., and accumulation of unburned fuel in the turbocharger and ex5aust system. The censequences of no load or light load operation are potential equipment failure due to the gum and varnish deposits and fire in the engine exhaust system.
2 Periodic surveillance testing should be performed in accordance with the applicable NRC guidelines (R.g.1.108), and with the recomendations of the engine manufacturer. Conflicts between any such reconnendations and the NRC guidelines, particularly with respect to test frequency, loading and duration, should be identified and justified, o *
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. OCT 3 0ig73 3.
Preventive maintenance should go beyond the norr.al mutine adjust-
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r ents, servicing an. repair of components when a malfunction'. occurs'.
I reventive maintenance should encompass investigative testing of
()mponents which have a history of repeated malfunctioning and require constant attentier. and repair.
In such cases consideration should be given to replacement of those components with other products which have a record of demonstrated reliabiltty, rather than repetitive repair and maintenance of the existing components. Testing of the unit after adjustments or repairs have been made only confirms that the eouipment is operable and does not necessarily mean that the root cause of the problem has been eliminated or alleviated.
4 Upon completion of repairs or maintenance and prior to an actual start, run, and load test a fina' equipment check should be made to assure that all electrical circuits are functional, i.e., fuses are in place, switches and circuit breakers are in their proper position, no loose wires, all test leads have been re.oved, and all valves are in the proper position to permit a manual start of the equipment. After the unit has been satisfactorily started and load tested, return the unit to ready automatic standby service and under the control cf the control room operator.
Provide a discussion of how the above requirements have been implemented in the emergency diesel generator system design and how they will be considered when the plant is in comercial operation, i.e., by what means will the above requirements be enforced.
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h pgog3 The availability on demand of an emergency diesel generator ts ~.
RSP dependent upon, among other things, the proper functioning of its controls and monitoring instrumentation. This equipment ts generally pa 21 mounted and tr some instances the panels are mounted directly on the diesel generator sktd. Major diesel engine damage has occurred at some operating plants from vibratton induced wear on skid counted control and centtoring instrumentation. This sensitive instrumentation is not made to withst.and and function accurately for prolonged periods under continuous vibrational stresses normally encountered with internal combustion cngines. Operation of senstive instrumentation under this ervironment rapidly deteriorates calibration, accuracy and control signal output.
Therefore, except for sensors and other equipment that must be directly nounted on the engine or associated piping, the controls and nonitoring instrumentat an should be installed on a free standing floor mounted panel separate from the engine skids, and located on a vibration free floor area or equipped with vibration counts.
Confirm your compliance with the above requirement or provide justification for noncompliance.
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