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Section 1 (first 2 Weeks) > Diesel and SBOGs > Flashcards

Diesel and SBOGs Flashcards

0
Q

What is each diesel generator designed to carry?

A

All power requirements of one train of safeguard equipment which in itself is capable of safely shutting down the unit and mitigating a LOCA.

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1
Q

What is the purpose of the diesel generator?

A

Function as a standby source of AC power for safe plant shutdown in the event of loss of preferred off site power.

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2
Q

How long after the diesel starts can it take full load?

A

designed to attain full load speed and accept load within 10 seconds after a cold start

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3
Q

What are the ratings for the diesel?

A

5500 kW continuous output or 6050 kW output for 2 hours out of 24 hrs.

Rated for 7670HP continuous or 8437HP short time

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4
Q

What signals will auto start a diesel?

A

SIAS - safety injection actuation switch (not loaded)
AFAS - aux feed water pump actuation signal (not loaded)
LOP - loss of power (loads after 10 seconds)
CSAS - containment spray actuation signal (not loaded and not running in Emergency Run unless SIAS is also present)

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5
Q

What does the PK system supply on the diesel generating system?

A

125vdc to the DC power feed #2, starting circuit, and engine panel.
Power to the generator low voltage control panels.
Field flashing for the diesel.

safety related interfaces

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6
Q

What does the NK system supply to the diesel?

A

NC 125vdc to diesel low voltage panel, instrumentation and alarms

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7
Q

What does the BOP ESFAS sequencer do?

A

SA is the abbreviation
Originates from BOP ESFAS DGSS module and DGSS contact closes when there is a LOP, AFAS, SIAS, or CSAS to start the diesel in emergency mode (test mode for CSAS).
If you lose the sequencer, you will have to manually sequence it.

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8
Q

What does the spray pond cool on the diesel generator?

A

Jacket water
Lube oil
Fuel oil
Inter cooler heat exchangers

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9
Q

How long can the diesel run without SP?

A

15 minutes unloaded

2.6 minutes loaded

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10
Q

What is the normal supply of makeup water to the diesel generator cooling water system?

A

Demineralized Water

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11
Q

What are the alternate sources for makeup water for the diesel generator cooling water system?

A

CT (condensate transfer)

Fire protection

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12
Q

Describe the operation of the Diesel engine.

A

There is a sprocket on the aft end of the crank shaft that drives the governors and camshaft through a chain.
A link driven sprocket and hub drive the oil, fuel, and water pumps.
Supercharging is done by an exhaust driven turbocharger located at the forward end of the engine.
Exhaust gases are forced out of the cylinders through a main valve overlap and the cylinders are subsequently charged with fresh cool air.
Combustion air is heated in the turbo charger during compression is cooled in the inter cooler

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13
Q

What does the crankshaft do?

A

Converts reciprocating motion of piston to rotational motion

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14
Q

What do the cylinder head and liner do?

A

Contain the inlet and exhaust valves & their operating mechanisms, an air start valve, and a fuel injector

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15
Q

What is the purpose of the turning gear?

A

It’s used only to do alignments.

Cranking air cannot start the engine when the turning gear is not fully disengaged.

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16
Q

What is the capacity of the fuel oil storage tank and what is the basis?

A

84,000 gallons.

Sufficient for 7 days continuous 100% rated output power levels plus 15% margin for testing.

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17
Q

Describe the fuel oil transfer pumps.

A

Capacity of more than twice the consumption rate of the diesel at full power.
Submerged in the fuel oil storage tank.
Powered from PHA-M31 & M32
Cycles in AUTO depending on day tank level

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18
Q

Describe the fuel oil transfer pumps.

A

One for each diesel.
Capacity is more than twice the consumption rate of the diesel at full power
Submerged in the fuel oil storage tank
Powered from PHA-M31 & PHA-M32
In auto, it cycles depending on day tank level

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19
Q

What is the high D/P alarm set point on the basket strainers?

A

2.5psid

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20
Q

What is the capacity of the fuel oil day tank and what is minimum level?

A

1100 gallons capacity
550 gallons minimum level by tech specs
(tank should supply 60 minutes with 10% margin assuming full rated load)

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21
Q

At what level in the day tank does the fuel oil transfer pump start?

A

731 gallons (enough for full load ops for 1.9 hrs)

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22
Q

What components make up the high pressure fuel subsystem?

A 
injection pump (positive displacement pump, driven by camshaft)
fuel injector
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23
Q

Where can the fuel oil transfer pump be manually operated from?

A

main control room or the diesel local panel

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25
Q

What is the flow path from the day tank to the generator?

A

Gravity flow from the day tank to a four element duplex strainer, then to the engine driven booster pump, then to a four element duplex filter, then the high pressure injection pumps. Injectors spray atomized fuel into the cylinder combustion chamber where it gets ignited by heat of compression.

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26
Q

Draw diesel generator jacket water system

A 
See drawing.  check for the following items:
Jacket water standpipe
motor driven jacket water circ pump
jacket water circ heater
engine driven jacket water pumpm
jacket water cooler ante temp control valve
intercooler heater sections
turbocharger
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27
Q

What supplies normal makeup water to the jacket water system?

A

Demin water

Condensate transfer and fire protection are backups

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28
Q

What can cause damage to the circulation heater if not monitored?

A

If water level is low in the jacket water system and the circ pump and heater are turned on, then the heaters can become damaged

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29
Q

When do the circ pump and circ heater cycle on and off?

A

on at 120F and decreasing, off at 135F and increasing

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30
Q

At what temperature does the thermostatic valve in the jacket water system direct all flow to the cooler?

A

175F or greater (all flow bypasses the cooler at 165F or less).
Goal is to maintain temp at 170F

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31
Q

What diesel loads are cooled by spray pond water?

A

Jacket cooling water
fuel oil cooler water
lube oil cooler water
intake intercooler

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32
Q

What are the three diesel emergency run trips?

A 
Low lube oil pressure
over speed (660RPM)
Generator differential (86 lockout)
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33
Q

What components make up the Diesel Air Intake and Exhaust Sub System?

A

Filter and Silencer
Overspeed shutdown butterfly valve
Heater/Intercoolers

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34
Q

What starts the Diesel Building HVAC units?

A

ESFAS load sequencer 25 seconds after diesel reaches rated speed and voltage

35
Q

Which starts first, the diesel essential AHU or the essential exhaust fan?

A

The AHU is slaved to the exhaust fan. both run until the room reaches 110F

36
Q

If the diesel start button is in Local, who can start it?

A

locally with the push button or receipt of the emergency start signal

37
Q

What does the emergency start push button simulate?

A

LOP or simulated ESF actuation

38
Q

What drives the diesel turning gear?

A

100 psig air

39
Q

Where is the diesel main governor mounted and driven from?

A

on the drive end of the engine and driven from the end of the left camshaft drive gear

40
Q

What is the position of the fuel racks upon start up?

A

Max or full fuel position and they stay there until 600 RPM

41
Q

At what speed does the diesel overspeed governor trip and how does it accomplish the trip?

A

660 RPM and it does it by applying the OFF air to the fuel control cylinder as well as tripping the overspeed butterfly valve to isolate combustion air

42
Q

What conditions must be met to AUTOMATICALLY close the DG output breaker?

A

LOP
Diesel at rated speed and voltage
no 86 lockout on the normal or alternate supply breaker
both normal and alteranate supply breakers open

43
Q

What conditions are necessary to close the output breaker manually from the breaker?

A

the breaker can only be closed on a dead bus since you can’t synch from the local breaker

44
Q

How can you tell if the diesel is running in emergency mode?

A

The “emergency mode” light on the engine panel will be lit
if the diesel starts automatically, it’s in emergency
if the diesel is started manually at the local panel using the emergency start pushbutton it’s in emergency

45
Q

What conditions exist when the DG is started in emergency mode?

A

Frequency is fixed at 60Hz

If the raise/lower switch is used it will only adjust the motor operated potentiometer and will have no affect on output

46
Q

Describe the three emergency mode shutdowns.

A

Over speed - governor trips; fuel shutoff valve & butterfly valve in the turbo charger air inlet trip; butterfly vlv must be manually reset.
Low oil pressure- two switches, one for emergency and one for test mode, bypassed for 20 seconds during s/u and s/d when RPM is < 570.
Generator differential - current into a winding is not equal to current leaving, trips the emergency mode fuel control solenoid. Must be manually reset.

47
Q

Describe droop mode.

A

Used when DG is in parallel. Affects governor and voltage regulator. When you load the DG governor lowers speed set point and voltage reg. loads voltage set point.

48
Q

Describe isochronous mode.

A

DG runs at constant frequency and voltage as load changes. Used when DG is tied to the bus or running in emergency mode. VR control mode is not to be transferred while diesel is running due to surges.

49
Q

How long is the cool down cycle for the diesel?

A

5 minutes

50
Q

Describe the emergency stop sequence.

A 
Run relays deenergize and run light off
Shutdown solenoid deenergized
Generator breaker trip signal
Engine stops (no cool down)
Warm up pumps are turned ON
51
Q

What happens to the diesel on a loss of control power?

A

Engine will trip; loss of tripping capability of output breaker
Won’t run in emergency mode
Output breaker can’t be operated remotely due to loss of control power.

52
Q

What happens to the diesel on loss of control air?

A

No effect during a startup in either emergency or test run because the fuel fuel control cylinder requires air to turn off the fuel

After it’s running, the only auto trip is the overspeed butterfly valve trip.

When started in test run mode, normal trips will only trip the output breaker.

When started in emergency run mode other emergency trips will only trip output breaker. Pneumatic trips will only start alarming as pressure decreases.

53
Q

How do you stop the diesel if you have no control air?

A

Take the main governor load limit control knob to minimum fuel position.
Hold manual fuel control handle in the off position until the generator stops
Manually trip the overspeed butterfly valve at the valve.

54
Q

Describe the flow path through the diesel air compressor

A

Air comes in through the air filter and into the first stage suction valve and piston
Air then goes to an intercooler
Enterst the 2nd stage and goes out through another intercooler
Enters the 3rd stage and exits through the aftercooler.

55
Q

What type of air dryers do we use on the diesel air system?

A

refrigerant air dryers

56
Q

What set points are associated with the diesel generator air compressors?

A

Normal pressure - 250psig
Compressor starts - 240psig and falling
Compressor stops - 250psig and rising
Relief valve lifts - 265psig

57
Q

What alarm is associated with the air receiver tanks?

A

185psig - low pressure alarm received if the pressure is not restored in 3 minutes or if the turning gear is engaged.

58
Q

What pressure is the air supplied to the turning gear?

A

100psig

59
Q

What are the functions of the DG Lube Oil system?

A

Maintain engine oil temp between 120-135F shutdown and <165F operating
Lubricate bearings and other moving parts
Keep engine warm to enhance immediate startup
cools pistons
prevents rust and corrosion

60
Q

What supplies oil to the diesel when the engine is running?

A

Engine driven main oil pump (Motor Driven oil pump operates <280RPM to keep oil warm and engine pre-lubed

61
Q

What temperature is the low lube oil temperature alarm?

A

115F (min temp is 105F for operability)

62
Q

What temp is the diesel main lube oil maintained at?

A

<165 when running (Thermostatic valve bypasses the cooler at 160F and full flow through the cooler at 170F)

63
Q

What D/P causes the alarm on the full flow oil filter?

A

25psid

64
Q

What pressure does the low lube oil pressure trip come in when the diesel is in emergency run?

A

30psig (Test - 1/4; Emergency 2/4)

65
Q

What cools the lube oil cooler?

A

Essential Spray Pond

66
Q

Draw DG Lube oil.

A

Verify the following items in drawing:
L.O. pump suction strainer, Eng. Driven L.O. pump suction check vlv and relief vlv, Eng. driven lube oil pump, Motor driven Warm up pump, L.O. circulation heater, L.O. cooler and TCV, Lube oil filters, Strainers, Lube oil to Engine bearings, Turbo l.o. filters, Header to turbo bearings.

67
Q

Why do we have SBOG’s?

A

NRC mandated that every station have a back up source of power for core safety in case of a loss of diesels or battery power. Diesels have proven unreliable in the past.

68
Q

How long do we have to start the SBOGs after station blackout?

A

1 hr loaded on PBA-S03

69
Q

What is a station blackout?

A

Loss of all AC power to one unit (loss of preferred off site power AND loss of on site standby emergency AC power) PK is all that is available.

70
Q

What is the output rating of the SBOG?

A

4270KW

71
Q

What are the three main components of a gas turbine?

A

Compressor, Combustor, and turbine

72
Q

Where does the compressed air go?

A

20% to combustion, 80% to cooling turbine blades

73
Q

The four processes that comprise turbine operation are:

A

compression, combustion, expansion, exhaust

74
Q

Is there a change in pressure in the combustion process in the turbine?

A

No. The rapid rise in temperature increases volume and flow velocity, but not pressure

75
Q

What are the major components of the SBOG?

A

Gas turbine, reduction gear, generator

76
Q

What is the purpose of the batteries at the SBOG?

A

Provide an independent source of DC power for blackout starts

77
Q

What does the diesel engine do during SBOG startup?

A

supplies rotational power to drive a hydraulic pump which provides pressure to drive a hydraulic motor to provide rotational force to start the turbine engine

supplies a source of atomizing air from external compressor (belt driven) to the air assist accumulator of the turbine engine

78
Q

What functions do the air system provide on the SBOG?

A

1) Combustion air - air from the compression portion of the turbine directed into the combustion chamber
2) Oil seal pressurizing air - prevents oil from leaking from the bearing into the engine air flow path (labyrinth seals)
3) Turbine cooling air - cools the turbine rotor disks.
4) Bleed air - unloaded from the combustor during acceleration to prevent engine from surging. Remains open until 90% speed and then closes. Re-opens at 90% on coast down.
5) Control air - indication and to control the fuel control valve. Pcd is the pressure signal to the fuel control valve.

79
Q

What cools the oil on the SBOG?

A

3 oil to air heat exchange radiators with an electric fan

80
Q

What does the lube oil system provide oil to?

A

engine rotating elements, hydraulic actuation of bleed air valve, variable guide vanes, and fuel valve actuator.

81
Q

What does the Turbotronic control system do?

A

sequence operating systems during startup, running and shutdown; provide protections during all phases of operation; and monitor package system parameters.

82
Q

How does the fire protection system detect a fire in the SBOG enclosure?

A

“Fire Eyes” detect light instead of heat and must be locked out prior to opening the doors on the SBOG or CO2 will be emitted.

83
Q

Describe the startup sequence for an SBOG.

A

1) Push Start
a) Pre/Post lube pump starts and runs for about 30 seconds.
2) Diesel starts
a) hydraulic pressure sent to hydraulic motor which turns the compressor and turbine
b) air compressor driven by diesel further charges air accumulator for fuel atomizing
c) at 30% speed SPRAG clutch is over run
3) Ignition
a) starting circuit opens fuel purge vlv and drains old fuel out (closes at 15%)
b) Fuel boost pump starts
c) 21% speed fuel control valve sends fuel to igniter torch and fuel injector. Atomizing air mixes with fuel and igniter torch is lit.
d) Bleed air valve is open and variable speed vanes are at minimum position to prevent surge and stall
e) As temp of air leaving combustor rises, turbine takes over load of turning the shaft.
4) Acceleration -
a) 66% is self sustaining; starting system disengages, pre/post lube pump runs for 3 min and then stops; atomizing air now supplied from compressor
b) bleed air vlv closes 90% and variable vane controller actuates open
5) Generation
a) 85% VR flashes field
b) 90% ready to load timer activated
c) 100% Governor control system takes over

all this in 1 minute 35 seconds

Section 1 (first 2 Weeks) (2 decks)

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