Exam 8 prep Flashcards
CPC, CEDMCS, ERFDADS, Plant annunciator
State the following trip setpoints for CPCs:
DNBR
LPD
Quality Margin
RCP speed
- DNBR: <1.34 Higher is better! Trip on LOW DNBR
- LPD: >21 kw/ft Lower is better! Trip on HI LPD
-
Quality margin feeds into the DNBR trip line after the DNBR calaculation
- Trips based on saturation in the outlet plenum
- RCP speed: <95% will trip the DNBR and LPD channels to protect against a 4 pump loss of flow event because the calculation isn’t fast enough
How does the RCP speed trip affect DNBR and why?
- DNBR receives a 0.1 multiplier thereby lowering DNBR to trip levels no matter what input.
- This happens every 50 msecs
What does DNBR and LPD protect against in the most limiting channel?
- For DNBR in most limiting channel it protects against clad damage
- LPD protects against fuel damage
What will cause a CWP - CEA withdrawal prohibit?
- PCRDL
-
CWP’s (CEA Withdrawl Prohibit)
- Pressurizer pressure (high) pre-trip (2 out of 4)
-
CPC pre-penalty (2 out of 4)
- Sub-group to group deviation 5 inches
- PSCEAs < 30” withdrawn
- < 7.5” between groups (Out-of-sequence)
- Not at the top or bottom of the core (+/- 10”)
- Reactor power cutback is set
- DNBR pre-trip (2 out of 4)
- LPD pre-trips (2 out of 4)
What are the power supplies to each CPC channel?
How is a rx trip prevented on energizing a CPC channel?
- CPC’s provided by power by its associated PN bus
- Prior to energizing a CPC channel need to BYPASS all parameters to prevent inadvertent trips.
What parameters make up the core ASI calculation?
- Core ASI (20 segments)
- Calculated by:
- Excore signals
- Shape annealing
- Target CEA positions
- Temperature Tc (For Rod Shadowing)
- Rod Shadowing
- Calculated by:
Explain the rule of 51 as it pertains to core ASI and CPCs.
-
Rule of 51
- On power going up @ a sum of 51% between the three ex-cores ASI shifts from a canned (constant) value for hot pin ASI to actual calculated ASI
- ~17% a detector (because: Math)
- On power going up @ a sum of 51% between the three ex-cores ASI shifts from a canned (constant) value for hot pin ASI to actual calculated ASI
How is core ASI value affected on a rx shutdown from 100 % power?
On power going down @ a sum of 45% between the 3 ex-cores ASI shifts from a calculated value of ASI to a canned hot pin ASI value
What calculates the AZ tilt for the core?
- Calculated by COLSS ONLY
How is AZ tilt used in CPC and what is an indication that this value is no longer valid?
- Input into to CPC is an ADDRESSABLE CONSTANT
- Uses this constant value in calculations no matter what
- The only way we know this value is no longer good is a control room alarm initiated by COLSS
- Which at this point the constant is no longer considered conservative so a new conservative constant must be entered
How is Tcold used in CPCs and what is talked about later?
- Tc uses (each CPC gets 2 of them from opposite loops)
- Minimum of the 2 goes to shadowing factors for ex-cores
- Maximum of the 2 goes to DNBR calculation
- Aux trip
- ≤ 505F or ≥ 590F
- Other things talked about later
What are the LPD penalty factors and parameters?
CRAP
- CEAC Penalty Factor
- Radial Peaking Factor
- Axial Peaking Factor
- Power (max)
What are the DNBR penalty factors and parameters?
CRAPFMP
- CEAC Penalty Factor
- Radial Peaking Factor
- Axial Reaking Factor
- Power Max
- Flow
- Max Tcold
- Pressure
How is DNBR calculation performed and updated?
- DNBR Calculation
- Static DNBR (Every 2 secs)
- Baseline DNBR calculated using Calibrated Ex-core
- Update DNBR (50 msecs)
- Changes Static DNBR by updating parameter info
- Flow Update (50 msecs)
- Worst case for DNBR so it’s the fastest
- Static DNBR (Every 2 secs)
Concerning CEACs, how are penalty factors applied?
When is a penalty factor not applied by CEAC?
Which deviation is worse?
-
Penalty factors start when a CEA is misaligned > 9”
- NO PENALTY FACTORS when within 10” of the top or bottom of the core
- Magnitude of the penalty factor depends on the following:
- Direction of deviation (out is much worse guaranteed immediate trip)
- Magnitude of deviation
- Type of rod (P.S., 4 finger, 12 finger)
How is the CEAC penalty factor applied and why?
- Once the deviation occurs an initial penalty factor is applied then over the next 6 hours the penalty factor will go up to its maximum value (Xenon Redistribution penalty factor)
List the AUX trips associated with CPCs.
PAT the VIP
- Processor fault
-
Assym steaming
- 20-50% S/P ramps from 35F – 20F
- 50-80% S/P ramps from 20F – 15F
- Protects against a closure of both MSIVs on the SAME generator at power
- Thot Sat.- within 19F of saturation
-
VOPT
- Rate of setpoint change 1%/min up and 16.67%/min down
- Step change: 8%
- High power: >110%
-
Input parameters
- Tc: 505F – 590F
- ASI: -0.5 – +.05
- PZR pressure: 1860 – 2388 psia
- Pumps - Less than 2 rcps running
ON the CPC power display,
What is displayed in red, green and when does the CEA deviation light come on?
-
Indications:
- Calibrated linear power: Red Pen
- Excore linear power: Green
- CEA Deviation light: Comes in @ 5.5” deviation of CEAs within a group
When RCS is > 300F, a loss of CEDM cooling requires CEDMs to be de-energized within how many minutes?
- RCS temp >300F or CEDMs must be de-energized within 40 minutes on a loss of cooling (in containment)
State the operating characteristics of the MG sets associated with CEDMCS.
- 200 kW
- Each powered from NGN-L03 & NGN-L10
- Converts 480VAC to 240VAC
- If only 1 MG Set energized then CEAs must be moved in Manual Individual ONLY. Prevents overloading the MG
- MG have flywheels that maintain power and frequency for up to 1 second for power transients
- On an SPS trip MG set contactors are opened along with RTSG breakers for redundancy
What do the UV coils de-energize at and what signals are sent out because of them?
- You must have 1&2 or 3&4.
- De-energize at ~ 180 VAC on a reactor trip they send signals to:
- MT/EHC – Initiates a turbine trip when the reactor is tripped
- DFWCS – Initiates RTO logic
- SBCS – Used in quick open block logic
- ERFDADS – Indication of reactor status
- SRP Multiplexer – SRP notification of unit trip
What is used to prevent CEDM coil burnout when CEAs are stationary?
Lower amount of current than when moving CEAs. This helps prevent coil burnout.
How is CWP - CEA Withdrawal Prohibit - bypassed when CWP is in?
- “CWP/B” Switch allows a CWP bypass must continuously hold it down while moving CEAs
What are the different modes of operation and how are CEAs moved in each?
-
Modes of Operation:
- Auto Sequential: RRS control CEA motion
- Manual Sequential: Joystick moves Groups of CEAs in a sequential order
- Manual Group: Moves selected group
- Manual Individual: Moves just a selected CEA
- Standby: Blocks all rod motion (Except trip or RPCB)
How is the operator alerted to an Out of Sequence condition with CEAs?
Can this alarm be in fast flash?
-
CEA Tech Spec Violation
- Annunciator: Comes in if group motion is “Out-of-sequence” according to the Plant Computer. This is if overlaps are not correct between regulating groups
- This alarm can be in fast flash(this is not PDIL alarm).
What will cause CEDMCS trouble alarm to come in?
-
CEDMCS TRBL
- Continuous CEA motion
- Continuous Gripper High Voltage
- Any sub-group on the hold bus (also get an SMA LED on local panel)
- MG set problems
Describe the CEA movoement including what each pulse does and the available speeds, when they can be moved and the reed switch locations.
-
CEA movements
- Each Pulse moves the CEA .75”
- Movement:
- Can go in @ 30”/min or 3”/min in AUTO
- Can go in or out @ 30”/min in MANUAL
- Can go out @ ONLY 3”/min when in AUTO SEQUENTIAL
- Reed Swtiches are located every 1.5”
What heights have unique reed switches in CEDMCS?
- Special reed switches
-
0” Rod drop contact (lights up the mimic)
- Resets the Pulse Counters
- 1 step (.75”) Lower Electrical Limit LEL
- 200 step (150”) Upper Electrical Limit UEL
- Need to remember REED SWITCHES feed these
-
0” Rod drop contact (lights up the mimic)
Describe both UGS and LGS.
- UGS – Stops all Outward CEA motion when in group mode
- LGS – Stops all Inward CEA motion when in group mode
- Both these are bypassed by moving rods individually
What is AWP - Automatic Withdrawal Prohibit - and what will insert an AWP signal?
-
AWP (Automatic Withdrawl Prohibit)
- Prevents automatic withdrawl of CEAs from RRS or SBCS
- RRS: Tavg > than Tref by 6F
-
SBCS: When there is a Steam Bypass Demand Signal
- TURB BYP DEMAND Annunciator
What is AMI - Automatic Motion Inhibit - and what signals will actuate it?
-
AMI (Auto Motion Inhibit)
-
RRS (every parameter must have average selected in RRS)
- TLI: 5% deviation between TLI signals
- Control Channel: 5% deviation between Control Channel
- Tavg: 5F deviation for Tavg signals (Loop 1 & 2)
-
SBCS
- <15% reactor power
- When Rx Power is < the AMI setpoint OR < the SBCS availability plus TLI (TLI has to be >15%)
-
RRS (every parameter must have average selected in RRS)
What is CWP - CEA Withdrawal Prohibit - and what signals will actuate it?
-
CWP (CEA Withdrawl Prohibit)
- HI PZR PRESS CH PRE-TRIP (any 2 of 4 Channels)
- LO DNBR CH PRE-TRIP (any 2 of 4 Channels)
- HI LPD CH PRE-TRIP (any 2 of 4 Channels)
- REAC PWR CUTBACK
- CEA misalignment generated from CPC’s/CEAC’s:
Where are the RTSG breakers operated from?
- RTSG breakers
-
Opened from:
- B05
- Locally
- PPS Cabinets
- SPLA Cabinets
-
Closed from:
- PPS Cabinets
- Locally
- SPLA Cabinets
-
Opened from:
How does a loss of NNN-D11 and/or NNN-D12 affect CEDMCS?
- Loss of NNN-D11 & 12
- Can withstand a loss of one but not both…..if both, rods go in
How does a loss of PNC-D27 or a loss of PND-D28 affect CEDMCS?
- Loss of PNC-D27
- ¾ rod bottom lights come in and resets the pulse counters for the effected CEAs
- Loss of PND-D28
- ¼ rod bottom lights come in and resets the pulse counters for the effected CEAs
What event led to the NRC requiring a system like ERFDADS at each nuclear plant in the country?
TMI
State the power supplies to ERFDADS and which one requires manual transfer.
-
Power Supplies:
- Primary: NKN-M45
- Backup: NHN-M08
- Backup: NHN-M72 (requires manual transfer)
What do the colors in ERFDADS represent?
-
Colors:
- Green: Good Data
- Magenta: Bad Data (out-of-range or loss of data link)
- White: Suspect Data
- Yellow: Exceeded a Level 2 alarm setpoint
- Red: Exceeded a Level 1 alarm setpoint
- Cyan: Manually inputted data
Concerning ERFDADS, what are the different levels of alarms?
- Alarms:
- Level 1: Preset alarms
- Level 2: Operator input alarms
Concerning ERDS, how soon must ERDS be activated?
What does ERDS provide?
-
ERDS
- Activated within 1 hour of declaring an ALERT or higher.
- Direct line to NRC
Concerning the leak rate detection portion of ERFDADS, how soon after a leak starts is the calculation considered accurate?
-
Leak Rate Detection
- CALCULATION of leak rate will not be accurate until 7.5 minutes AFTER the leak has started
Concerning the P/T curves, what do the different colors mean?
- The button will indicate grey when normal
- Changes to yellow when NPSH is exceeded
- Changes to red when subcooling is exceeded
Concerning ERFDADS, how is data stored and archived?
How is this different for PTARS?
- Done in 14 hour loops
- ERFDADS
- 1 sec snaps on a continuous 14 hour loop
- PTARS
- 0.1 sec snaps on a continuous 14 hour loop
- A 16 day file taking 1 min snaps is also stored.
How is data stored surrounding events associated with a Rx trip?
-
When a trip occurs it saves the data from 2 hours prior to the trip and records all data from 12 hours after the trip and then saves this to the STANDBY file.
- From there the data can be moved to a SECONDARY file location and transferred to a .DAT file.
What does a fast flashing first trip annunciator tell the operator?
What if that parameter is bypassed and is in a tripped condition?
Why is this a problem?
- First trip annunciator flashes faster than others
-
If a parameter is bypassed AND is in a tripped condition the first out annunciator still sees that as a trip signal. This means that if an additional channel on the same parameter trips the first out annunciator will alarm.
- This can also mask the real reason for the trip
What are the power supplies for the Class annunciators?
What is the rule of 58?
- Class Annunciators
- PKA-D21 & PKB-D22
-
Rule of 58! (Non-class annunciators) Normal seeking transfer switch
- RKN-CO1 ( ½ the annunciators)
- NKN-D43 w/ NNN-D15 backup
- RKN-C02 ( ½ the annunciators)
- NKN-D42 w/NNN-D16 backup
- THERE WILL BE A POWER LOSS QUESTION. Really understand how things like a SIAS w/ a LOOP combined with a loss of DC power effects this. Remember NNN-D16 in Unit 3 is not SIAS load shed.
- RKN-CO1 ( ½ the annunciators)
What functions do the following buttons perform?
Alarm Ack:
Flasher Reset:
Lamp Reset:
Test:
-
Buttons:
-
Alarm Ack
- Ack alarms on all boards. Leaves in fast flash
- Windows in fast flash will not provide audible if another alarm comes in on same window
- Only button that affects all boards
-
Flasher Reset
- Changes fast flash to slow flash (if alarm is clear)
- Changes fast flash to locked in (if alarm still in)
-
Lamp Reset
- Changes slow flashing to off
-
Test
- Test all alarm windows on associated board
-
Alarm Ack
What do the following sounds indicate to the operator with regard to RK system?
-
Sounds:
- Repeating Chime: Indicates alarming condition
- Single Chime: Alarming condition returning to normal
How does a loss of NKN-M45 during a SIAS affect Unit 1 and 2 RK vs Unit 3 RK?
- Loss of NKN-M45 and SIAS = loss of all RK (Units 1-2);
- loss of half of RK (Unit 3)
