ML20091A261
| ML20091A261 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 05/26/1977 |
| From: | Mayer L NORTHERN STATES POWER CO. |
| To: | Desiree Davis Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9105140467 | |
| Download: ML20091A261 (5) | |
Text
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iiigutatory b *-
NORTHEMN STATES POWER COMPANY wiw ~ a a ou.. wis u a. ora.. oi n
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Mr D K Davis, Acting Chief
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Operating Reactors Branch #2
)2,/J);rtpp-e Division of Operating Reactors U. S. Nuclear Regulatory Comission Washington, DC 20555
Dear Mr. Davis:
MONTICELLO NUCLEAR GENERATINC PLANT Docket No. 50-263 License No. DPR-22 Response to 4/7/77 Letter on Diesel Generators As requested by your April 7,1977, letter to L. O, hbyer concerning Emergency Diesel Cencrator operability and alarm indications, the following infomation is submitted:
a.
Alarmed conditions that render the diesel generators incapable of re-sponding to an automatic emergency start signal are listed below:
NOTE: 'lhe alanns listed are the exact wording as it appears on the control room annunciator window except the wording is preceeded by the designation No.11 or No.12 depending on which of the two diesel generators is involved.
Condition Alam
- 1. " Auto-Local" hLad switch on the 1.
Diesel Cenerator Not In Auto, engine control panel in the 2.
Diesel Cenerator hbintenance local position.
Lockout.
3.
Diesel Cenerator Trouble.
2.
Engine control switch in 1.
Diesel Cenerator Not In Auto, control room in pull to lock 2.
Diesel Generator hbintenance position. Switch has posi-Lockout *
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tions of pull to lock, stop, auto, and start with spring 3.
Diesel Generator Trouble, return to auto from stop and start.
771520i d 9103140467 770526 PDR ADOCK 05000263 P
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Condition Alam 3.
Overspeed trip (Trip has 1.
Diesel Cenerator Not In Auto, to be manually reset).
2.
Diesel Cencrator hhintenance Lockout.
3.
Diesel Cenerator Troubic.
4.
A.C. control power drcuit 1.
Diesel Cenerator Not In Auto, breaker open.
2.
Diesel Cenerator bhintenance lockout.
3.
Diesel Cenerator Tmuble.
5.
D.C. contml power circuit 1.
Diesel Cenerator Not In Auto, breaker open.
2.
Diesel Cenerator bhintenance Lockout.
3.
Diesel Cenerator Trouble.
6.
Start system #1 control power 1.
Diesel Centrator Not In Auto.
circuit breaker open and start 2.
Diesel Generator thintenance system #2 control power circuit
- Lockout, breaker open.
3.
Diesel Cenerator Trouble.
7.
Exciter circuit breaker open.
1.
Diesel Cenerator Not In Auto.
2.
Diesel Cenerator thintenance Lockout.
3.
Diesel Cenerator Trouble.
8.
Cenerator phase overcurrent 1.
Diesel Cenerrtor lockout.
relay trip. Must be manually reset. There is an addition-al approach alam before the lockout.
9.
Cenerator differential over-1.
Diesel Cencrator Lockout, current relay trip, hbst be manually reset.
s 10.
Cenerator anti-mo.toring relay 1.
Diesel Cenerator Lockout.
trip. bbst be manually reset, b.
The conditions that carse the same annunciators listed above to alam but do not render the diesel generator incapabic of responding to an automatic emergency start signal are listed below:
Alam Condition 1.
Diesel Cenerator Not In Auto.
1.
Alam control power circuit breaker open.
2.
Start system #1 control power cir-cult breaker open or start system
- 2 control power cTrcuit breaker open.
Alam Condition 3.
Starting air compressor #1 or start-ing air compressor #2 control switch-es in the off position.
2.
Diesel Generator Fbintenance 1.
Alam control power circuit
- lockout, breaker open.
2.
Start system #1 control power cir-cuit breaker open or start system #2 control poaer circuit breaker open.
3.
Starting air compressor #1 or start-ing air compressor #2 conttui switch-es in the off position.
3.
Diesel Generator Trouble.
1.
Low lule oil pressure.
2.
High crank case pressure.
3.
Low cooling water pressure.
4.
Insufficient voltage following an emergency start.
5.
Unit not at 0 rpm within 15 minutes following a stop signal.
6.
Loss of field voltage relay during operation.
7.
Generator circuit breaker not closed within 1 second following reaching 870 rpm during a fast start.
8.
High or low level in the fuel oil base tank.
9.
Low starting air pressure.
- 10. Engine coolant high temperature.
11.
Lube oil low level.
12.
Lube oil high tempetature.
- 13. Three unsuccessfull automatic start attempts.
- 14. Service water / emergency service water low pressure.
- 15. High fuel pump pressures (electric driven or engine driven).
- 16. Alarm control power circuit breaker open.
17.
Start system #1 control power circuit breaker open or start system #2 control power circuit breaker open.
4 Alam Condition 18.
Starting air compressor #1 or starting air campressor #2 control switches in the off position, c.
The conditions that render the diesel generator incapabic of responding to an automatic emergency start signal which are not alamed in the control room are listed below:
1.
The loss of D.C. control power to the generator output circuit breaker prevents the generator output circuit breaker froat automatically closing.
Light indication above the breaker hand switch will be Icst if there is no control power available to close the breaker, 2.
The generator output circuit breaker control switch in the contml room in the pull-to-lock position will prevent the generator output circuit breaker frm automatically closing.
It requires deliberate operator action to place the hand switch in this position.
3.
The loss of D.C. power to the diesel generator control power circuit (which also supplies the alam control power circuit) or to the gen-exator field flashing circuit will render the diesel generator in-capable of responding to an automatic emergency start signal.
d.
There are no proposed modifications resulting from this evaluation. All alamed conditions are imnediately investigated by operating personnel to detemine the cause of the problem, to detemine the status of diesel generator involved and to take the necessary corrective actions. The non-alarmed conditions involve loss of D.C. power sources or a deliberate action by a control room operator. Considering the reliability of the D.C.
power supply system, the routine surveillance testing perfomed on the emergency diesel generators, the once per shift inspections of control room switch and indicating light status, and the redundancy of the diesel generators, additional alams are not deemed necessary.
The area of particular concem noted in your April 7th letter invoht g an unreset condition following a local manual stop of the diesel generator does not apply to the hbnticello diesel generator system. When a stop signal is given to the diesel generator from either the control room or the local panel, the diesel engine idles for 15 minutes before shutting down. If during the shut-down cycle an automatic emergency start signal is received, the engine re-turns to operating spet;d and is ready to accept load if required. After the 15 minute idle time has elapsed, the engine shuts down, the governor is driven to the synchronous speed setting and the unit is ready to accept an automatic emergency start signal.
Yours very truly, h.
L 0 Mayer, PE Manager of Nuclear Support Services LQ4/MHV/ead cc: J G Keppler G Charnoff MPCA-Attn:
J W Ferman
v.s. uvest aei eis e.vt At on, Gouviaioas asoccic o cavem a liic ili.6 tot,
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->tr. D. K. Davis.
Minneapolis, Minnesot a DAtt rit etivt o L. O. Mayer 5/31/77 inevvroHM NUMlat f) or corit s fit CLIvt D g,1 s t n Quotoriir t o e nor Oco'Y
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Consists of requested inf orniats an regarding g
IEmergency Diesel Generator. operability and i
alarmi i ndi ca t i ons.......
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DISTRIliUTION OF MATEltIAL CONCERNING DIESEL D
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