Control Elment Drive Mechanism Control System (CEDMCS) Flashcards
1
Q
What is CEDMCS used for ?
A
-Develops control voltage to withdraw, hold, or insert CEAs
2
Q
What’re Control Element Assemblies(CEA), also known as control rods, used for?
A
Used to control fission rate of reactor power
3
Q
What does CEDMCS allow CEA groups to compensate for reactivity changes ?
A
CEA movement controls:
-power in core
-variations in moderator temp & boron concentrations
-Dampens axial xenon oscillations
4
Q
How does CEDMCS allow CEAs to drop into the core ?
A
CEAs drop into core upon interruption of power to Control Element Drive Mechanism(CEDM) Coil Stack
5
Q
What system does CEDMCS send a signal too upon a reactor trip ?
A
-Main Turbine
-Feedwater control system
-Steam bypass control system
-Emerg. Response Facility Digital Acquisition Display System(ERFDADS)
-SRP Plant Multiplier
6
Q
Why does CEDMCS provide signals for CEA positioning ?
A
CEA position is used as an indication to assure reactivity control has maintained plant within safety limits
7
Q
What provide powers the Legacy CEDMCS system ?
A
Non-Class 480VAC Load Centers
-NGN-L03
-NGN-L10
8
Q
What is the generators output voltage for the Legacy CEDMCS ?
A
Out out of generator is 240VAC that is sent through load contractor & circuit interrupters
9
Q
What is the normal operation for the Legacy CEDMCS Motor generator set?
A
Both of the Motor Generators are operating in parallel
10
Q
What does Reactor Protection System do for the CEDMCS system ?
A
Reactor Protection System will interrupt power going through Reactor Trip Switchgear Breakers deenergizing CEDMCS cabinets to trip reactor
11
Q
What is a Power Switch Assembly used for on the Legacy CEDMCS ?
A
Rectifies 240VAC into 60VDC and sends it to Control Element Drive Mechanisms(CEDM) coil stacks in the associated subgroups
12
Q
Where does CEDMCS accept CEA motion signals from ?
A
-Reactor Regulating System(RRS)for automatic control
-Operators module on board 4 manual control
13
Q
What does the Power Switch Assembly do when it’s receives a CEA motion signal demand ?
A
PSA will supply appropriate power to the CEDM coils to either hold, withdraw, or insert CEAs
14
Q
Where does CEDMCS receive demand control signals for CEA operations for Legacy CEDMCS ?
A
-Reactor Power Cutback system
-Plant Computer
15
Q
What do the Legacy Motor Generator Sets do ?
A
Convert 480VAC power from NG system into 240VAC power from CEDMCS system
16
Q
What is the generator rated at ?
A
-200kW
-240VAC
-60HZ
-601Amperes
17
Q
What’re the Flywheels meant for on the Motor Generators ?
A
Provide rotational inertia for MG set during momentary transients
18
Q
If MG set loses all power for 1 second, what’re the parameters it should maintain supplying full load?
A
-voltage shouldn’t decrease more than 5% below 240VAC
-Frequency shall not decrease below 58Hz
19
Q
What set points do under voltage and under frequency relay initiate a MG trip ?
A
-Under voltage will trip at 210VAC
-Under frequency will trip at 57Hz
20
Q
Why should both MG sets be running before moving CEAs?
A
They have to be running before CEAs are moved in:
-Auto Sequential
-Manual Group
-Manual Sequential
21
Q
How is CEA motions limited to when only ONE MG set is operating ? Why must motion be limited ?
A
-Limited to Manual Individual to minimize potential of slipping or dropping rod
22
Q
Whatre the controls in Square Black Line meant for on the each MG set control panel ?
A
The controls inside the square black line are meant to control the other MG set
23
Q
What’re the controls located inside the MG set control panel ?
A
3 MG set overloads reset pushbuttons
-Motor Running Overload
-Motor Starter Overload
-Generator Running Overload
Two MG set high vibration resets located on each MG set
24
Q
What should be done when there are a row of red alarm lights going across MG control cabinet ? How’re the red lights reset ?
A
Problem should be addressed via:
-Operating procedure
-Alarm Response Procedure
Pushbutton on each MG set control cabinet is for manually resetting local light and alarm input
25
What’re the two Voltage adjustment switches available on MG control Cabinet ?
-Automatic Voltage Adjust
-Manual Voltage Adjust
26
What is the difference when adjusting voltage for a single MG set & a MG set operating in parallel ?
-MG operating individually adjust generator output voltage indicated by voltmeter
-MG set operating in parallel are adjusted by sharing load indicated by ammeter on both control panels
27
What is the Motor Contactor ?
Pushbutton on MG set panel to start the motor
28
What is the Circuit Interrupter used for on the MG control panel ?
Manually operated circuit breaker for generator output
29
What is the Neutral interrupter used for on the MG control panel ?
Manually operated circuit breaker for Generator output neutral line
30
What is the Load Contactor used for on the MG control panel ?
A Pushbutton used to quickly open/close a contact inline with 240VAC circuit breaker
31
What is used for disconnecting/ connecting MG set to/from system besides the Circuit Interrupter ?
Load Contactor is rather used than manually operating Circuit interrupter
32
What will trip open the Load Contactor ?
-Generator Overload
-Under frequency @ 57Hz
33
What is the MG out put voltage for the ARCH system ?
Output voltage of the MG set is 240VAC
34
What is the normal operation between the two MG sets on the arch system ?
MG sets are operated in parallel
35
What is the 240VAC flow path ?
1.)240VAC output of MG set
2.)Goes through MG cabinet & output circuit breaker
3.)Then goes through parallel Reactor Trip Switchgear Breakers
4.)Then go to common 240VAC bus which is distributed through Coil Power Management Drawers
36
How many CPMDs does each disconnect switch supply ?
Each disconnect Feeds 3 Coil Power Management Drawers
37
Why does each CPMD have a disconnect ?
Each CPMD has a disconnect for isolation
38
What does each CPMD rectify 240VAC down to ?
CPMD rectifies 240VAC down to 60VDC to apply it to CEDM Coil
39
Where does CEDMCS Log Cabinet accept CEA motion demand signals ?
-Reactor Regulating system(RRS)for Automatic Control
-Ovation CEDMCS operators module in control room for Manuel control
40
Which subgroups receive signals from Reactor Power Cutback System ?
Subgroups 4,5,& 22
41
What do the Rod Drive Power Supply(RDPS) Motor Generator sets(MGs) provide to CEDMCS ARCH system ?
Supplies power to Advanced Rod Control Hybrid(ARCH) to operate CEDM which hold or move CEAs
42
Where do the RDPS MG receive there power supply from ?
NGN-L03 & NGN-L10 supply power
43
What is selective tripping function for the RDPS MG ?
-Ensures only one MG set is taken offline in event of a single failure
-Other set will be able to maintain power to CEDMCS
-Allows offline MG set to get repaired and to keep the plant online
44
Is a single MG set capable of operating & maintaining the ARCH system without any limitations?
Yes
45
Why does each MG set for the ARCH system have a Flywheel ?
-Provides rotational inertia for momentary transients
46
During a total loss of power to MG set for one second, what should the generator output voltage & frequency not drop below ?
-Output voltage shouldn’t drop below 5% below 240VAC
-Output frequency should not decrease below 58Hz while at full load
47
Where does Rod Drive Power Supply Control Cabinet receive its power from ?
-Supplied from non class 480MCC Dpanel at 120 VAC
48
Where does the 120VAC coming from RDPS Control Cabinet supply power to ?
-Backup 24VDC power supply
-Generator Field Flash Power Supply
49
What is the Backup 24VDC power supply used for in the RDPS Control Cabinet ?
-Rectifies 120VAC->24VDC
-Then supplies power to Critical & non-critical MG control circuits when MG set output breaker is open
-This allows control of system for startup before generator field is flashed
50
Where does Generator Field Flash Power Supply receive its power from ?
The RDPS Control Cabinet Power supplies 120VAC to Generator Field Flash Power Supply
51
What does the Generator Field Flash Power Supply do ?
-Rectifies 120VAC—>48VDC
-Provides power to voltage regulator for flashing of Generator Field
52
How is field flashing accomplished ?
Accomplished by Pushbutton on the front of the Control Cabinet
53
Once Generator field if flashed & generator output voltage is present what happens to the 24VDC power supply ?
-Switch will align output voltage to Backup 24VDC power supply
-A separate switch aligns power to primary 24VDC power supply
54
What happens to Backup 24VDC power supply if the MG set trips ?
If generator trips then switch realign back to external 120VAC power supply from RDPS Control Cabinet Power
55
Where does the auctioneered Primary 24VDC power & Backup 24VDC power supply to ?
Supply power to Critical & Non-Critical circuits that provides redundancy in case of failure
56
What’re non-critical components for the MG set ? (Failure won’t take system offline)
-HMI
-cRIO
-Ovation interface equipment
-MG set space heaters
57
What charges the MG output breaker closing spring charging motor ? When will it get charged
-Primary 24VDC Power Supply
-Closing springs will charged once generator field is flashed
58
What is the 48VDC Field Flashing Power Supply used for ?
Used to apply voltage to Rotor Field Windings
59
How long should the field flashing be held ? What happens if it takes longer ?
-Should not be held any longer than 2-3 seconds
-possible something may be wrong in the circuit if it takes longer
60
What mode is the voltage relgulator in when only one MG set it running ?
It’s in isochronous mode to maintain constant output voltage regardless of load
61
What mode is the voltage regulator when both MG sets are in parallel ?
Voltage regulator will be out into droop mode to help two MGs share reactive load equally
62
When a voltage regular is operating in isochronous mode how is output voltage adjusted ?
Will be manually adjusted until it has a steady 240VAC coming out
63
How is circulating current generated between Two paralleled MG sets ?
-Develops due to mismatch in output voltages and indicated by unequal reactive loading
64
What is actually happening between Two MG sets when circulating current is happening ?
Mismatch voltages will send current from generator to the other which could cause excess heat damaging insulation
65
What happens if circulating current gets to high ?
Could trick ground fault relay into thinking there is a ground fault and Trip the MG set
66
What’re the requirements for closing MG set output breaker ?
-No fault,alarm,or trip
-must be closed on dead bus
OR
-Paralleled in sync with other MG set
67
What will happen upon a Generator Ground Fault ?
-Generator protection relay will activate alarm
-Ground Fault Light will illuminate ground fault lamp
-will occur on both MG set cabinets
68
How do you clear the Generator Ground Fault common trouble alarm on the MG set control cabinets ?
-Press the trouble reset Pushbutton
-Allows other alarms to announce problems when fixing Ground Fault alarm
69
What must be done to the clear Ground Fault Flashing Light when the ground fault is corrected ?
Fault reset Pushbutton to clear alarm
70
What is the Generator Protection Relay provide ?
Monitors critical parameters and determined when MG set output breaker can be closed
71
What pushbutton controls does the MG set control cabinet have ?
-Motor start
-Motor stop
-Field Flash
-Generator Connect
-Generator Disconnect
-Trouble Reset
-Fault Reset
-Lamp Test
72
With the space heaters switch in the ON position what will space heater do ?
-Energize when motor isn’t running
-De-energizes when motor is running
73
Where are the Reactor Trip Circuit Breakers normally operated from ?
Manually operated from the control room
74
What’re the Control Element Drive Mechanism(CEDM) used for ?
Physically interact with CEAs to hold or move based on command from CEDMCs
75
What’re the two magnetic-jack mechanisms inside RCS pressure boundary ?
-Engage CEA drive shaft when magnetic field is generated
-Disengage CEA drive shaft when there’s no magnetic field
76
What’re the Upper latches operated by ?
-Upper lift coil
-Upper latch coil
77
What’re the lower latches operates by ?
-Lower lift coil
-Lower latch coil
78
What’re the four multi bay cabinets used for ?
Contains equipment to provide power to coils of CEDM & CEDM magnetic jacks for holding/moving CEAs
79
What does NN 120VAC provide to CEDMCS cabinet equipment operation ?
-Logic power supplies
-Relay Power supplies
-Aux.power supplies
80
What does Normal Lighting(QA) supply power to into the CEDMCS cabinet ?
-Blowers
-Lighting
-Utility Outlets
81
How many bays does each CEDMCS cabinet have ?
Contains 5 bays
82
How many circuit breakers does each PSA have?
There are 4 circuit breakers one for each CEA in its subgroup
83
What do the Subgroup Logic Cards do for PSAs?
PSAs supply rectifies DC power to CEDM coils based on signals from Subgroup Logic Cards
84
What does continuous flashing mean for card status monitor lights & ACTM lights ?
Means there is an active problem with card
85
What does several flashing lights with brief pause mean for the Card Status Monitor & amber ACTM lights?
Means there was an abnormality, but it no longer exists
86
What is the row of 13 amber “Card Status Monitoring” indicating lights mean on the front of the CEDMCS cabinet ?
Correspond to Internal logic cards (1-15 ODD numbers only )
87
What is the row of 8 amber indicating lights on front of CEDMCS panel ?
Corresponds to internal ACTM cards (Labeled A-H)
88
What is the row of 8 red “Timer Failure” indicating lights on front of CEDMCS panel ?
Internal ACTM card(Labeled A-H)
89
What is row of 4 red “continuous Gripper High Voltage” indicating lights for on front of CEDMCS panel ?
Correspond to logic cards of the same numbers (7,9,17,19)
90
What do the 4 continuous Gripper High Voltage lights mean ?
Indicates corresponding Coil Driver Card has lost his Logic Supply Power & has failed to apply voltage to CEDM Upper Gripper Coil
91
Where do all three Logic power supplies receive its power from? What is it rectified to ?
-NN 120 VAC
-rectified down to 10VDC
92
Logic Power supplies PS1 & PS2 are auctioneered and powers what ?
-Logic & ACTM cards in Subgroup Logic Housing for respective CEDMCS cabinet
-PSA breaker indicating lights
93
What happens when Subgroup Logic Housing Coil Driver Cards has low voltage ?
Will initiate “Continuous Gripper High Voltage” that’ll need to be corrected in 10 MINUTES
94
What does the Aux. Power Supply(AUX PS) power ?
Internal components of the Power Switch Assembly
95
How do you know if a Logic Power Supply fuse has been blown out ?
A amber covered light will illuminate
96
What does the Relay Power Assembly contains ?
-Two relay power supplies(PS1 & PS2)
-One analogue voltmeter for each power supply
-On/Off indicating light for each power supply
-7 fuses
97
Where do both relay power supplies receive power from ? What does it get rectified down to ?
-NN 120VAC
-Rectified down to 24VDC
98
What do relay power supplies provide power to ?
-Under voltage detectors
-Cabinet temperature sensors & alarm circuits
99
How many blowers does each cabinet bay have ?
Has two blowers intake blower at bottom and exhaust blower on top
100
What is the breaker panel on left of entryway supplies 120VAC instrument power to ?
Logic Power Supplies
Relay Power Supplies
101
What is the breaker panel on rear access door to CEDMCS cabinet right of the entry way supply Normal Lighting to ?
-Intake blower
-Exhaust Blowers
-Internal lighting
-Internal utility outlets
102
What is Hold Bus Power Supply used for ?
Subgroup transferred to hold bus when there is control circuitry malfunctions(Logic Cards or Logic Power Supply )
103
What is in upper panel of the Hold Bus Control & Indicator Panel ?
Four bus under voltage test switches that test operation of common 240VAC bus undervoltage detectors
104
What happens if you activate any of these test switches in the upper panel ?
Will illuminate local red light & annunciate alarm in control room
105
What happens when you activate both switches simultaneously ?
Will trip reactor and signal rest of plant to respond accordingly
106
What is the lower panel used for on the Hold Bus Control & indication panel ?
-Thumbwheel subgroup selector used to select which subgroup to transfer to hold bus
107
What is the Transfer Switch used for in the Lower Panel of the Hold Bus Control & indication panel ?
Applies power from Hold Bus Power supply to selected subgroups upper gripper coils
108
If a subgroup transferred to the hold bus which gripper coil will it transfer to ?
Originally subgroup power supply uses Upper gripper coil
Hold bus transfer will use Lower Gripper Coil
109
What does the Reset Toggle switch do for the Hold Bus Power Supply ?
Disconnects Hold Bus Power Supply from the selected subgroup Upper gripper coils and restores normal power supply to subgroup
110
What’re the three CEA Relay Interface Housing Cards ?
-One card interfaces Reactor Power Cutback & CEDMCS
-Other two provide up-count & down-count signals for each increment of CEA motion to plant computer
111
What is the 18 red “cooling failure” LEDS meant for in the advisory panel ?
Indicates overheating condition exits for specific cabinet and bay
112
What is the row of 13 RED CEDMCS Status LEDs in the Supervisory Panel ?
Indicate CEDMCS is operating under restricted or abnormal conditions
113
What is the bottom row of 12 red”Shutdown Group Disable” indicate on the Supervisory panel ?
-Indicates that corresponding shutdown Group Disable switch has been set to disable
-These switches are used for testing during startup
114
What are the 14 red “group motion” LEDS indicating on the sequential Reset Panel ?
Indicates corresponding group sequencer is operating
115
What is totalizer panel assembly used for ?
Totalizeer is used on each CEA assembly advances one count every time it’s CEA is raised or lowered one step
116
What’re the Automatic CEDM Timer Module used for ?
ACTM cards control sequencing of coil voltages to CEDM in order to insert or withdrawal
117
Where does ACTM cards receive their digital inputs from ?
They’re received from other circuits within CEDMCS & in response controls CEDM, which in the end controls CEAs
118
What does the ACTM card monitor for each CEDM coil ?
-Prevent CEA drop & slip
-Prevent CEDM coil burnout
-Provide up & down count signals for accurate CEA position monitoring
-Prevent CEA group deviations
119
When will the ACTM card automatically transfer CEA to alternate gripper ?
-High Voltage
-Inadequate holding current
120
What happens if there is movement of CEA when there isn’t supposed to be ?
There will be a LG/UG transfer is initiated to transfer the CEDM to other gripper
121
What is the new gripper hold feature of the CPMD?(ARCH)
What does this new feature provide that the old legacy system didn’t ?
-If there is a fault in upper gripper then it auto engages lower gripper
-This eliminates the need for a hold bus to provide an alternate power source to UG to prevent Rod drops
122
Where is power to operate CPMD come from ?
NN 120VAC from NNN-D11 & NNN-D12
123
What power normally powers Ovation controllers? What is the backup power to ovation ?
-Receives normal power from NN 120VAC
-Receives backup power from a UPS Battery Backup to help with transients
124
How long does each UPS provide power for Ovation during a LOOP ?
-Provides 4 minutes with Max ovations loads
-Provides 13 mins with normal loading until DG start and supply the MCC
125
How does NN Dpanel supply two drawers within each CPMD?
NNN-D11 supplie UL & UG drawers
NNN-D12 supplies UG & LL drawers
Dpanel are auctioneered to supply backup power for each other on a loss of power
126
What is the Ovation Interface used for ??
-Used to manually move CEA from control room
-Automatic motion commands from Reactor Regulating Systems(RRS)
127
What do the Ovation Controllers send to the ARCH coil Power Management Drawers ?
They send required command signals to perform CEA movement
128
What’re the normal automatic features for the CEDMCS ?
Reactor Regulating System can automatically move Regulating Groups to control RCS temp within band
129
What initiates a Reactor Power Cutback ?
-Main Turbine Load Rejection
-Main Feedwater Pump Trip
130
What subgroups do CEDMCS automatically drop during a reactor power cutback ?
4,5,& 22
131
What happens on a loss of power to a single CEA ?
Will result in that single CEA drop into core
132
What happens on a loss of power to a PSA ?
Would result in associated PSA subgroup to drop all its rods
133
How does CEDMCS interface with 480VAC LoadCenter NG ?
-Provides power to Legacy MG sets
-Provides power to Rod Drive Power Supply MG set
-Provides 120VAC from a NG Dpanel to CEDMCS cabinet internal lighting,utility outlets, & cooling fans
134
How does CEDMCS interface with NN ?
-Provides power to Logic Power
-Relay Power Supplies
ARCH:
-Coil Power Management Drawers( CPMD)
-Ovation Controllers
135
How does CEDMCS interface with 120VAC Instrument power (PN) ?
-PN provides power to CEDMCS Aux. Cabinets
-PNC & PND provide power to ovation control room Thin Clients
136
How does CEDMCS interface with Aux Building HVAC(HA) ?
-CEDMCS room air handling units provide cooling to CEDMCS cabinets
-CEDMCS room temp should be between 55-104
137
How does CEDMCS interface with Containment Building HVAC (HC) ?
CEDM Normal Air cooling units provide cooling to CEDM coils and CEA reed switch position transmitters
138
How does CEDMCS interface with SRP plant Multiplexer ?
CEDMCS provides SRP plant multiplexer a signal when reactor has tripped
139
How does CEDMCS interface with Main Turbine ?
CEDMCS sends undervoltage relay provide signal to Main Turbine to trip Turbine on a Reactor Trip
140
What signals does CEDMCS send to Digital Feedwater Control following a reactor trip ?
-Downcomer and Economizer Feedwater Control Valves Closed
-Downcomer Feedwater Control Valves throttled into SG based on reactor coolant temp
-This design it to prevent overcoolinh RCS following a Reactor Trip
141
What happens on a loss of NGN-L17 or NGN-D03 to CEDMCS cabinet ?
-Cabinet cooling fan
-internal lights
-Utility outlets
