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LOIT Systems 2019 > Exam 8 prep > Flashcards

Exam 8 prep Flashcards

CPC, CEDMCS, ERFDADS, Plant annunciator

1
Q

State the following trip setpoints for CPCs:

DNBR

LPD

Quality Margin

RCP speed

A
  • 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
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2
Q

How does the RCP speed trip affect DNBR and why?

A
  • DNBR receives a 0.1 multiplier thereby lowering DNBR to trip levels no matter what input.
  • This happens every 50 msecs
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3
Q

What does DNBR and LPD protect against in the most limiting channel?

A
  • For DNBR in most limiting channel it protects against clad damage
  • LPD protects against fuel damage
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4
Q

What will cause a CWP - CEA withdrawal prohibit?

A
  • 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 30” withdrawn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)
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5
Q

What are the power supplies to each CPC channel?

How is a rx trip prevented on energizing a CPC channel?

A
  • 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.
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6
Q

What parameters make up the core ASI calculation?

A
  • Core ASI (20 segments)
    • Calculated by:
      • Excore signals
      • Shape annealing
      • Target CEA positions
      • Temperature Tc (For Rod Shadowing)
      • Rod Shadowing
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7
Q

Explain the rule of 51 as it pertains to core ASI and CPCs.

A
  • 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)
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8
Q

How is core ASI value affected on a rx shutdown from 100 % power?

A

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

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9
Q

What calculates the AZ tilt for the core?

A
  • Calculated by COLSS ONLY
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10
Q

How is AZ tilt used in CPC and what is an indication that this value is no longer valid?

A
  • 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
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11
Q

How is Tcold used in CPCs and what is talked about later?

A
  • 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
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12
Q

What are the LPD penalty factors and parameters?

A

CRAP

  • CEAC Penalty Factor
  • Radial Peaking Factor
  • Axial Peaking Factor
  • Power (max)
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13
Q

What are the DNBR penalty factors and parameters?

A

CRAPFMP

  • CEAC Penalty Factor
  • Radial Peaking Factor
  • Axial Reaking Factor
  • Power Max
  • Flow
  • Max Tcold
  • Pressure
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14
Q

How is DNBR calculation performed and updated?

A
  • 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
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15
Q

Concerning CEACs, how are penalty factors applied?

When is a penalty factor not applied by CEAC?

Which deviation is worse?

A
  • 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)
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16
Q

How is the CEAC penalty factor applied and why?

A
  • 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)
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17
Q

List the AUX trips associated with CPCs.

A

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
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18
Q

ON the CPC power display,

What is displayed in red, green and when does the CEA deviation light come on?

A
  • Indications:
    • Calibrated linear power: Red Pen
    • Excore linear power: Green
    • CEA Deviation light: Comes in @ 5.5” deviation of CEAs within a group
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19
Q

When RCS is > 300F, a loss of CEDM cooling requires CEDMs to be de-energized within how many minutes?

A
  • RCS temp >300F or CEDMs must be de-energized within 40 minutes on a loss of cooling (in containment)
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20
Q

State the operating characteristics of the MG sets associated with CEDMCS.

A
  • 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
21
Q

What do the UV coils de-energize at and what signals are sent out because of them?

A
  • 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
22
Q

What is used to prevent CEDM coil burnout when CEAs are stationary?

A

Lower amount of current than when moving CEAs. This helps prevent coil burnout.

23
Q

How is CWP - CEA Withdrawal Prohibit - bypassed when CWP is in?

A
  • “CWP/B” Switch allows a CWP bypass must continuously hold it down while moving CEAs
24
Q

What are the different modes of operation and how are CEAs moved in each?

A
  • 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)
25
Q

How is the operator alerted to an Out of Sequence condition with CEAs?

Can this alarm be in fast flash?

A
  • 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).
26
Q

What will cause CEDMCS trouble alarm to come in?

A
  • 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
27
Q

Describe the CEA movoement including what each pulse does and the available speeds, when they can be moved and the reed switch locations.

A
  • 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”
28
Q

What heights have unique reed switches in CEDMCS?

A
  • 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
29
Q

Describe both UGS and LGS.

A
  • 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
30
Q

What is AWP - Automatic Withdrawal Prohibit - and what will insert an AWP signal?

A
  • 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
31
Q

What is AMI - Automatic Motion Inhibit - and what signals will actuate it?

A
  • 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%)
32
Q

What is CWP - CEA Withdrawal Prohibit - and what signals will actuate it?

A
  • 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:
33
Q

Where are the RTSG breakers operated from?

A
  • RTSG breakers
    • Opened from:
      • B05
      • Locally
      • PPS Cabinets
      • SPLA Cabinets
    • Closed from:
      • PPS Cabinets
      • Locally
      • SPLA Cabinets
34
Q

How does a loss of NNN-D11 and/or NNN-D12 affect CEDMCS?

A
  • Loss of NNN-D11 & 12
    • Can withstand a loss of one but not both…..if both, rods go in
35
Q

How does a loss of PNC-D27 or a loss of PND-D28 affect CEDMCS?

A
  • 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
36
Q

What event led to the NRC requiring a system like ERFDADS at each nuclear plant in the country?

A

TMI

37
Q

State the power supplies to ERFDADS and which one requires manual transfer.

A
  • Power Supplies:
    • Primary: NKN-M45
    • Backup: NHN-M08
    • Backup: NHN-M72 (requires manual transfer)
38
Q

What do the colors in ERFDADS represent?

A
  • 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
39
Q

Concerning ERFDADS, what are the different levels of alarms?

A
  • Alarms:
    • Level 1: Preset alarms
    • Level 2: Operator input alarms
40
Q

Concerning ERDS, how soon must ERDS be activated?

What does ERDS provide?

A
  • ERDS
    • Activated within 1 hour of declaring an ALERT or higher.
    • Direct line to NRC
41
Q

Concerning the leak rate detection portion of ERFDADS, how soon after a leak starts is the calculation considered accurate?

A
  • Leak Rate Detection
    • CALCULATION of leak rate will not be accurate until 7.5 minutes AFTER the leak has started
42
Q

Concerning the P/T curves, what do the different colors mean?

A
  • The button will indicate grey when normal
    • Changes to yellow when NPSH is exceeded
    • Changes to red when subcooling is exceeded
43
Q

Concerning ERFDADS, how is data stored and archived?

How is this different for PTARS?

A
  • 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.
44
Q

How is data stored surrounding events associated with a Rx trip?

A
  • 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.
45
Q

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?

A
  • 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
46
Q

What are the power supplies for the Class annunciators?

What is the rule of 58?

A
  • 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.
47
Q

What functions do the following buttons perform?

Alarm Ack:

Flasher Reset:

Lamp Reset:

Test:

A
  • 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
48
Q

What do the following sounds indicate to the operator with regard to RK system?

A
  • Sounds:
    • Repeating Chime: Indicates alarming condition
    • Single Chime: Alarming condition returning to normal
49
Q

How does a loss of NKN-M45 during a SIAS affect Unit 1 and 2 RK vs Unit 3 RK?

A
  • Loss of NKN-M45 and SIAS = loss of all RK (Units 1-2);
  • loss of half of RK (Unit 3)

LOIT Systems 2019 (20 decks)

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