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41 Cards in this Set
- Front
- Back
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Fuel Oil System -
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Provides sufficient fuel oil to the diesel engines for all loading conditions for at least seven days of continuous operation.
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Purpose of EDG
Air Start System |
- Supplies high pressure air sequentially to the cylinders to roll the engine to initiate a start of the D/G and be ready to accept load within 10 seconds of a Start signal.
- Provides instrument control air to the Air Coolant System temperature control valve. - Provides operating air to the piston pump for the aft bearing oil booster. - Provides operating air to the hydraulic accumulator for the governor power piston boost. - Provides a long term air supply to the C, A and N SRV's in the event PCIG is unavailable due to fire. |
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Purpose of EDG
Combustion Air Intake and Exhaust Systems |
- Supplies adequate combustion air and disposes of exhaust products to permit continuous full load operation.
- Removes crankcase vapors from the engine and disposes of them with exhaust products. |
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Purpose of EDG
Jacket Water Cooling System |
- Cools the engine cylinder and turbocharger jackets and combustion air in order to permit full load operation.
- Maintains jacket water in a warmed condition while the D/G is in a standby condition to promote starting. |
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Purpose of EDG
Lube Oil System |
- Supplies a continuous flow of oil to all surfaces requiring lubrication at controlled pressure, temperature, and cleanliness.
- Warms and circulates the oil when the D/G is in standby to promote starting and to prevent extreme lube oil viscosities. |
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Purpose of EDG
Diesel Enclosure HVAC |
- Maintains suitable ambient air temperatures for D/Gs and aux. during all modes of operation.
- Two 50% capacity exhaust fans, with adjustable pitch blades, per cell - Fans take a suction on enclosure cell and discharge to outside surroundings - Fans controlled from local panel - Each cell equipped with two unit heaters (1) Supplied by aux. Steam (2) Fan circulates warm air (3) Thermostat controlled - Greater than 75ºF Outside Air Temperature, both fans are required for D/G operability. - Less than or equal to 75ºF, one fan is required for operability. |
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Diesel Enclosure HVAC fan Auto starts and trips
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(1) One fan in AUTO, one fan in STANDBY
(2) AUTO fan starts on Hi Hi Temp [110ºF] OR on associated diesel start (3) STANDBY fan starts on Hi Hi Temp [110ºF] OR Hi Temp when diesel is running (4) AUTO fan shuts off when temp below Hi Temp [95ºF] with diesel shutdown (5) STANDBY fan shuts off when temp below Hi Temp [95ºF] |
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Fuel Oil Storage Tank required supply
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- Four fuel oil storage tanks per unit, each with a capacity of 41,500 gallons. Tech. Spec. minimum level 33,500 gal - 9'7" indicated, which is a 7 day supply.
- A 7 day supply is assured by limiting loading on the Diesel Generators if the engines are running carrying their respective buses following a LOCA |
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Day Tank required supply and fuel oil transfer pump trip auto start and trip
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- 850 gal. Capacity. That is enough fuel for 4 hrs of continuous full load operation.
- Tech Spec is 250 gal. or 40" indicated level. That is enough oil for 1 hour of operation @ full load. - Make up to day tank is via fuel oil transfer pump - Controlled by 2 position switch-Auto/Hand. Switch is normally in auto which starts the pump on Day Tank low level. - Pump trips on high day tank temperature (150ºF) |
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Air Start System, Compressors and Receivers
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Each D/G has two independent air start systems. Each air start system consists of:
- One compressor - AC powered, 20 HP, 44 cfm. Each one can press up both receivers. Normally aligned to respective receiver only. Handswitch normally in auto which runs compressor on low pressure in receiver (228 psig); and shuts off on high pressure (243 psig). Each compressor sized to be able to press up both receivers in 30 minutes. - One receiver - each sized to provide enough air for at least 5 starts, although testing shows that each can actually provide up to 13 starts. The D/G will not start if air pressure is <80 psig. - One solenoid operated air start pilot valve - becomes energized by the Start relays and repositions to vent the diaphragm of the air start valve. Backed up by a manual vent which would be used in the event of a loss of control power. - One Air Start Valve - when operating air is vented, opens to admit air to the air start header and the air start distributor. - One Air Start Header - receives the air to be admitted to the cylinders to start the D/G. - One Air Start Distributor - a rotating cam which actuates the pilot air valves in order of firing sequence. - Six Pilot Air Valves - admits control air to the pistons of its respective air start check valve, opening that check valve. - Six Air Start Check Valves - open to admit air from the air start header to its respective cylinder. - The engine will begin to fire, come up to speed and then the low speed relay (LSR) will dropout the starting relays, securing supply air to the start system. - Vent paths integral with the pilot valves and check valve housings will vent off the starting air, seating the check valves and withdrawing the pilot valve plungers from the cam to minimize wear. The solenoid operated vent valves, just downstream of the air start valve, are redundant and are operated by the start relays. |
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diesel generator output breaker trip
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Remote Shutdown Panel Transfer switch in the "normal" position and C661 control switch in "Trip" or "Pull to lock" positions.
OR - Either Safeguard feed closed (101 or 201) and EDG output breaker closed and LOCA signal (0.5 sec duration trip). OR - 4KV Bus Lockout due to differential overcurrent or overcurrent or ground fault on bus (trips all breakers on bus). OR - Diesel Engine Tripped OR - Diesel Generator Lockout due to Generator Differential Overcurrent or Generator Neutral Overcurrent OR - Anti-Motoring OR - Diesel Generator output breaker phase overcurrent. |
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EDG Trip initation
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Jacket coolant high temperature (2 out of 3 logic) [195ºF]
Jacket coolant low pressure (2 out of 3 logic) [9psig] Generator ground neutral overcurrent. Generator lockout. Lube oil low pressure (2 out of 3 logic) [23 psig] Lube oil high temperature (2 out of 3 logic) [190ºF] Engine overspeed Diesel generator differential overcurrent generator lockout - May be bypassed on D11 - HS-092-186A on 1A-C514 in FIRE position will isolate a fire induced circuit fault t allw the diesel generator to be restarted. Manual |
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EDG Trip initation that are active in LOCA
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Engine overspeed
Diesel generator differential overcurrent generator lockout - May be bypassed on D11 - HS-092-186A on 1A-C514 in FIRE position will isolate a fire induced circuit fault t allw the diesel generator to be restarted. Manual |
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Engine Controls must be aligned for Auto Start
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(1) Local - Remote Transfer switch at the local control panel is in the "Remote" position. This enables auto start and control room start. This disables local engine start at the local control panel.
(2) Control Room Diesel control switch must be in the "normal" position to allow diesel automatic start on a dead bus or LOCA signal. (3) Diesel Generator Lockout Relay (86) is reset. (4) Start Failure Relay (SFR) and Engine Trouble Shutdown (ETS) are reset - SFR and ETS relays are reset using the "Engine Shutdown Reset" pushbutton at the local panel (5) 125V DC Control power is available to start and trip circuits. (6) Engine is at rest, low speed relay and high speed relays are both de-energized (i.e., < 200 rpm) |
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EDG Dead bus start conditions
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Normal 4KV Bus feed is tripped open
- AND - 4KV bus voltage < 40% of normal - AND - Alternate 4KV bus feed fails to close within 0.5 sec (3) Output breaker closes on dead bus start but only if the diesel is ready to load and the 4 KV bus and Diesel Generator Lockouts are not tripped. |
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EDG LOCA start conditions
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LOCA signal (LOCA signal taken from Core Spray initiation logic. Manual initiation of a Core Spray Division also starts the respective diesel.
- -129" Reactor water level - OR- 1.68 psig drywell pressure AND < 455 psig reactor press |
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EDG Low speed relay functions
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(5) Engine fires and speed increases to greater than 200 rpm
(6) Low speed relay energizes performing the following functions: (a) Disarm start and cranking time control relays (b) De-energizes the standby lube oil and jacket water keep warm systems, pre-lube pump, and D/G space heater (c) Initiates generator field flash (d) Enables voltage regulator and governor remote control circuits unless diesel generator automatically started (e) Energize combustion air temperature control valve (f) Enables auto start of D/G enclosure vent exhaust fan (g) Enables auto start of ESW pump (after nominal 53 second time delay) Unsuccessful start causes start attempt to be aborted if 200 rpm is not reached within 7 seconds (only in the event of an automatic or remote manual start) |
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EDG high speed relay functions
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(7) At 800 rpm the high speed relay energizes performing the following functions:
(a) Alarm delay relay is energized (b) Alarm delay relay is TDC (10 seconds) to enable protective trips and de-energizes DC auxiliary fuel oil pump |
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steps necessary to swap a diesel generator to droop mode with a LOCA signal present
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If D/G starts in AUTO, D/G in Isochronous mode which disables MCR speed governor and voltage regulator control
- There are two (2) steps to place D/G in Droop mode: - Depress “Diesel Generator Auto Start Signal Bypass” pushbutton on C661 panel. (1) This energizes a 3 minute time delay dropout relay (TDDO) (2) 3 minute timer starts when pushbutton is released (3) With TDDO relay energized, LOCA start and DBS start relays de-energized - Place D/G control switch on C661 to “Start” BEFORE 3 minute TDDO relay times out - “D/G AUTO Start Bypass” pushbutton must be depressed approximately every 2 ½ minutes with LOCA signal present or the LOCA start relay will re-energize and convert D/G governor to isochronous. - If LOCA signal is no longer present, the LOCA signal may be reset. Jumpers may be installed at local panel in D/G bay in lieu of depressing pushbutton. |
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effect on EDG of a loss of
starting air |
- Failure of one air receiver will not prevent diesel from starting - 5 starts from one air receiver design
- Failure of both air receivers will prevent D/G start - Failure of one starting air distribution will not prevent D/G start - Failure of one air compressor will not prevent D/G operation - one air compressor may feed both air receivers |
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effect on EDG of a loss of
fuel oil pump |
- Failure of the engine driven fuel oil pump will not prevent D/G start or operation due to DC pump acting as a backup
- Failure of DC fuel oil pump may increase start time of D/G - will not affect D/G during operation |
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effect on EDG of a loss of
lube oil pump |
- Failure of D/G lube oil circulating system may cause increase in D/G start time due to decrease in lube oil temperature
- Failure of prelube pump will not prevent D/G operation but will increase wear on moving parts. - Loss of lube oil will cause a D/G trip at all times except on LOCA start - during LOCA significant damage to D/G will occur |
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effect on EDG of a loss of
jacket water cooling |
- Failure of air cooler loop would cause a reduction in D/G capacity
- Failure of jacket water loop will trip the D/G during all modes of operation except LOCA start - Failure of jacket water warming loop will cause an increase in D/G start times due to lower engine temperature prior to starting |
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effect on EDG of a loss of
electric governor |
- The mechanical governor will take over and provide backup control of the engine upon a loss of signal from the electric governor.
- Governor actuator is directly coupled to engine via fuel oil pump drive from lower crankshaft |
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Droop vs. Isochronous:
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Governor will be in droop mode only on a Remote Manual Start. Droop = Parallel; i.e. allows changing of speed for the purpose of paralleling with an offsite source.
Isochronous = Constant Speed; governor will be in Isochronous on any Auto start and Local start. Mode designed for D/G to pick up a dead bus, no speed adjustment required, frequency will remain constant at 60 HZ. |
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Engine response to manipulation of controls
- Standby |
(1) With engine running in standby, placing the speed governor control in raise or lower will raise or lower engine speed and generator frequency
(2) With engine running in standby, placing voltage regulator control in raise or lower will raise or lower generator voltage |
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Engine response to manipulation of controls
- Parallel |
(1) With engine running in parallel, placing the speed governor control in raise or lower will raise or lower generator real load (KW)
(2) With engine running in parallel, placing voltage regulator control in raise or lower will raise or lower generator reactive load (KVAR) |
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Engine response to manipulation of controls
- Isochronous |
(1) Following an auto start due to a LOCA or LOOP, speed governor and voltage regulator controls will not function until governor is converted to droop
(2) Following a local start, if the LOCAL/REMOTE switch is placed in REMOTE, speed governor and voltage regulator controls will function which may allow the diesel to be synchronized in isochronous |
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EDG Normal/Fire Bypass Switch (D11 and D21 only)
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- With switch in “Normal” position, all speed governor and auto voltage controls work as described above.
- With switch in “Fire” position, MCR speed governor and auto voltage controls are disabled, but local controls are still enabled. - These circuits were modified as part of the Thermo-Lag Reduction Mod to provide a means to bypass/isolate a postulated fire-induced cable fault and allow the D/G to be controlled locally. NOTE: The same switch on D11 bypasses the D/G Differential Overcurrent Lockout input to the Emergency Stop Relay (5E). The D21 switch does NOT have this contact and can NOT bypass this trip. |
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DC Fuel Oil Pump Operation on D/G Start Up
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- On a remote manual or auto start, the DC fuel oil pump starts when the D/G start relay is energized
- Shuts down when the D/G reaches 800 rpm - Will auto restart if fuel oil pressure is <10 psig - Once the low pressure restart has actuated, then pump will not shut off until the engine is shutdown or the pump is manually shut off |
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EDG Prelube Pump
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- rotary positive displacement pump 30 gpm at 20 psig. Provides lubrication prior to manual startups.
- Remote manual start automatically starts the prelube pump. - Local manual start - prelube pump is manually started. - Runs on a timer for 180 seconds. - Prelube pump does not run on an auto start. |
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EDG Electric Governor Controls
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Droop setting is adjusted using a locally set potentiometer.
- The electric governor is placed in the droop mode when the engine is started from the Control room. - Speed setting may be adjusted from the control room unless the diesel was started by a LOCA or DEAD Bus signal. - Remote manual start relay is energized to place the electric governor in the droop mode. Must remain energized to keep the governor in the droop mode. Speed <200 rpm resets the governor to 60 Hz. Auto start signal places the governor in isochronous mode and sets governor to 60 Hz. |
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Condensate Transfer Pumps loads
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- Two condensate transfer pumps and a jockey pump supply water, from either CST, to plant loads such as ECCS keep fill, Radwaste demin backwashing, solid radwaste piping flushes, and refuel floor hose connections.
- The condensate transfer pumps are single stage, centrifugal pumps with a capacity of 600 gpm each. |
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Condensate Transfer Pumps start and trip
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- Condensate Jockey and Transfer pumps will trip on low level in the selected CST (29 feet).
- The LEAD Condensate Transfer pump runs continuously - The LAG Condensate Transfer pump will automatically start if it's switch is in "AUTO" and high demand causes header pressure to drop to the low pressure starting setpoint. When demand is reduced sufficiently, as sensed by low flow, the lag pump will automatically stop. This arrangement (start on low pressure/stop on low flow) prevents the lag pump from cycling; as could occur if only pressure were used for both functions. |
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Refuel water pump auto start and trips
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Refuel Pumps
- Refuel Water pumps trip on low RWST level (4 feet) - A Refuel Water pump in "AUTO" will start as required by a Condensate Filter Demin Backwash cycle. - The lead Refuel Water Transfer pump is normally operated in RUN to prevent water hammer when starting a condensate filter backwash. - A Refuel Water pump in "STBY" will start as required by a Condensate Filter Demin Backwash cycle if header pressure is low (100 psig for 5 seconds). |
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CST High and Low trips
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- Low CST level (29 feet) in the CST selected as the suction source will cause the Condensate transfer pumps to trip.
- High CST level (40 feet ) will cause the hotwell reject valves for the corresponding unit to automatically close. |
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Identify the major components supplied by the CST and RWST
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HPCI, RCIC, Core Spray, Condensate, and Refuel Water Transfer, and the Hotwell.
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loads supplied by the demineralized water header
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- Condensate and Refuel Water Storage Tanks
- Fuel Pool Skimmer Surge Tanks - RECW - TECW - Auxiliary Boilers - SLC - Radwaste System - DWCW - CECW - Chemistry Lab - Plant demineralized water hose stations - GEZIP System |
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Demin Water Transfer and Jockey Pumps
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- Demineralized Water Transfer Pumps (one normally in service) are controlled from the MCR panel 20C655. Switches are STOP-START type.
- Demineralized Water Jockey Pump (normally OFF) is controlled from local panel 00C548 with a STOP-START type of switch. - All pumps trip on DWST Lo-Lo level. |
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4 subsystems associated with the Water Treatment Plant and the purposes
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- Raw water treatment - Clarify and filter raw river water and store it for usage in other subsystems.
- Lube water – Provide cooling and seal water to the seals of all circ water pumps for both units. - Waste Treatment - Collect, process, transfer and store wastewater form various sources within the Water Treatment Plant. - Makeup Demineralizer - Take clarified water from CWST and purify it via the Ionics Reverse Osmosis (R/O) Trailer. |
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Load Center Bus Breakers Control Power
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480/120 VAC Control Power Transformer taps off between LC Transformer and LC Bus Breaker (control power is restored, even if respective breaker is not closed in on the bus)
- Supplies 120 VAC control power for all breakers on LC Bus - Each Load Center Breaker has two (2) solenoid coils to operate the breaker - The closing coil releases the closing springs when energized to close the breaker - The trip (opening) coil releases the opening springs when energized to open the breaker - Without control power breakers can only be operated via manual controls at breaker - "PREFERRED SOURCE" and "NON-PREFERRED SOURCE lights - Preferred source is usually LC powered from 11 Bus for Unit 1, 21 Bus for Unit 2 or the Unit 1 LC for common LC - Control Power Transfer Switch - PREF-NORMAL-NONPREF switch - Selects source of control power - Transfer switch is spring returned to normal |
