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.AR LOIT Systems: Welch's Highlighted Notes > .AR PLCS PPCS (Welch's Highlighted Notes) > Flashcards

.AR PLCS PPCS (Welch's Highlighted Notes) Flashcards

1
Q

Pzr Level Transmitters (LT-110X and 110Y):

  • Selectable input to PLCS.
  • LT power: ?
  • LT Output to PLCS power: ?
  • LT-110X and Y:
    • ?
A

Pzr Level Transmitters (LT-110X and 110Y):

  • Selectable input to PLCS.
  • LT power: PNA-D25 (110X) and PNB-D26 (110Y).
  • LT Output to PLCS power: NNN-D12 (110X) and NNN-D11 (110Y)
  • LT-110X and Y:
    • RSP and PAM LIs (LCO 3.3.10 / 3.3.11)
    • Hi / Lo level alarms (60% / 25%)
    • Hi / Lo level deviation from setpoint alarms (+8.5% / -3.5%)
    • LT-110X - PAM recorder
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2
Q

Program Level Generator:

  • Based on RRS…?
  • < 568°F Tave:? constant at 33%
  • > 586°F Tave: ?
  • 568 - 586°F: level setpoint is ramped linearly…?
    • ?
A

Program Level Generator:

  • Based on RRS Tavg (Loop 1, 2, or average)
  • < 568°F Tave: LPZR constant at 33%
  • > 586°F Tave: LPZR constant at 52.6%
  • 568 - 586°F: level setpoint is ramped linearly from 33% to 52.6% (15% to 100% power).
    • Low end of band keeps heaters covered / available
    • High end of band maintains a PZR bubble for proper pressure control
    • Insurge will not reach safety nozzles
    • Outsurge will not drain PZR on a Reactor trip from 100%
    • Containment loading is determined by volume of RCS and size of PZR. Ensures design limits are not exceeded during LOCA
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3
Q

Master Level Controller (LIC-110, aka Level Setpoint Control)

  • Red pointer: ?
  • Black on white pointer: ?
  • Black pointer: ?
  • Outputs (0-100%): ?…
  • Controller in automatic mode (remote or local setpoint): ?…
  • Shifting LIC between Remote Auto and Local Auto is ….?
    • ​Place LIC in manual…why?…
A

Master Level Controller (LIC-110, aka Level Setpoint Control):

  • Red pointer: actual level from selected channel (LT-110X or LT-100Y)
  • Black on white pointer: remote setpoint from RRS (based on Tavg)
  • Black pointer: local setpoint from thumbwheel.
  • Outputs (0-100%):
    • Sends status to RRS to prevent testing unless PLCS is NOT in Remote/Automatic (PLCS in LOCAL or MANUAL).
    • Inputs to Level Error Deviation Program. (If in LOCAL)
    • Compares actual level (selected) to the level setpoint.
    • LIC output controls letdown LCVs (LV-110P/Q).
  • Controller in automatic mode (remote or local setpoint):
    • Output is modified by a “lag” unit before being applied to the letdown control valves.
    • Lag prevents rapid valve motion. Prevent unwanted pressure transients in the letdown line.
    • Low flow limit (~30 gpm). Adequate charging pre-heat to prevent RCS charging nozzle thermal shock.
    • Upper flow limit (~135 gpm). Ensures letdown does not exceed maximum design flow rates.
    • Lag and flow limits bypassed in manual control (0-150 gpm)
  • Shifting LIC between Remote Auto and Local Auto is break before make.
    • Place LIC in Manual prior to changing modes (prevent change in controller output)
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4
Q

Letdown Control Valves…?

A

Letdown Control Valves:

  • LV-110P/110Q SELECTOR (Select one or both)
  • Normally only one is selected. (One is normally isolated locally)
    • Use BOTH up to 1000 psia during startup and when < 1050 psia during shutdown.
    • Prevents exceeding letdown relief valves capacity (< 1200 psia).
  • Fail closed (loss of air / power NNN-D11).
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5
Q

Charging Pump Controls

  • 1-2-3, 1-2-3, 2-3-1 and 3-1-2
    • “Always Running” - “Normally Running” - “Standby” Charging Pump.
  • Controls operation of the charging pumps in conjunction with charging pump HSs.
  • HS in AUTO after stop (green flagged) allows PLCS to control, manual pump start (red flag) blocks PLCS level deviation signals
  • Pumps controlled from level deviation program (bistables).
  • “Always Running” – PLCS has no control
  • “Normally Running”
    • +15% ↑ stops normally running pump (level is too high)
    • +14% ↓ starts normally running pump (level returning to program)
  • “Standby”
    • -23% ↓ starts standby pump (level is too low)
    • -14% ↑ stops standby pump (level returning to program)
A

Charging Pump Controls:

  • 1-2-3, 1-2-3, 2-3-1 and 3-1-2
    • “Always Running” - “Normally Running” - “Standby” Charging Pump.
  • Controls operation of the charging pumps in conjunction with charging pump HSs.
  • HS in AUTO after stop (green flagged) allows PLCS to control, manual pump start (red flag) blocks PLCS level deviation signals
  • Pumps controlled from level deviation program (bistables).
  • “Always Running” – PLCS has no control
  • “Normally Running”
    • +15% ↑ stops normally running pump (level is too high)
    • +14% ↓ starts normally running pump (level returning to program)
  • “Standby”
    • -23% ↓ starts standby pump (level is too low)
    • -14% ↑ stops standby pump (level returning to program)
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6
Q

Pressures:

1837 to 2750…?

A

Pressures:

2750 psia – RCS Safety Limit

2500 psia – RCS design pressure

2475 psia – PZR safeties open

2409 psia – SPS HP trip (ATWS)

2383 psia – HP reactor trip (PPS)

2300 psia – Spray full open

2295 psia – DNB (LCO)

2285 psia – HP alarm / heaters trip

2275 psia – Spray starts to open

2250 psia – NOP

2225 psia – P1/P2 full ON

2200 psia – BU Htrs ON

2160 psia – LP alarm

2130 psia – DNB (LCO)

1837 psia – Rx trip / SIAS / CIAS (PPS)

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7
Q

Power Supply Summary:

NNN-D11:

  • ?

NNN-D12:

  • ?

NKN-D42:

  • ?
A

Power Supply Summary:

NNN-D11:

  • Level controls (LIC and Letdown LCVs)
  • ‘Y’ PT and LT

NNN-D12:

  • Pressure controls (MPC and Spray Valve Controller)
  • ‘X’ PT and LT

NKN-D42:

  • Powers all bistables (level deviations, pressure B/Ss, 25% cutout)
  • Charging pump PLCS controls
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8
Q

Pressure Transmitters (PT-100X, PT-100Y):

  • ?
  • Power Supplies:
    • ?
  • ?
A

Pressure Transmitters (PT-100X, PT-100Y):

  • Two non-class PTs (narrow range: 1500-2500 psia). Inputs to:
    • PPCS
    • SBCS to bias the modulation and permissive setpoints and inputs to Quick Open and LLR signal.
    • PMS (COLSS)
  • Power Supplies:
    • NNN-D11 supplies PT-100Y
    • NNN-D12 supplies PT-100X
  • Pressure Control Channel selector switch (selects one PT for input to PPCS)
  • Deviation alarm at 50 psid between the PTs
  • Low Pressure Alarm ≤ 2160 psia (Reset at 2200 psia) (either PT)
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9
Q

High Pressure Heater Cutout / Alarm (Bistables):

  • ?

Backup Heater Control Bistables:

  • ?
A

High Pressure Heater Cutout / Alarm (Bistables)

  • ≥ 2285 psia (Reset at 2275 psia):
  • De-energizes all PZR heaters (selected PT only)
  • High Pressure Alarm (either PT)

Backup Heater Control Bistables:

  • ≤ 2200 psia (Resets at 2225 psia)
  • ON-OFF control for backup heaters (Selected PT only)
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10
Q

PLCS Input to PPCS:

  • +3% level deviation? (resets at +?%):
    • ?
  • ≤ 25% Low Level Heater Cutout? (resets at ?%)
    • ?
A

PLCS Input to PPCS:

  • +3% level deviation (resets at +2.5%):
    • Energizes all backup heaters (if < 2285 psia, level > 25%, and HS is not in OFF or PTL)
    • Heaters energized in anticipation of a large insurge of cooler water to maintain saturated conditions in the PZR
    • Reduces the duration of degraded pressure control due to unsaturated conditions.
  • ≤ 25% Low Level Heater Cutout (resets at 27%)
    • Trips all heater breakers
    • Circuit powered from NKN-D42.
      • Loss of power would prevent remote heater operation. Could operate locally. (LCO 3.0.3 until control regained)
    • PZR LT(s) selected by the PZR HTR Control Level Trip Selector Switch. Normally BOTH are selected.
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11
Q

Pressurizer Heaters:

Bank

Power

Control Power

Capacity

P1:?

P2:?

B1: ?

B2: ?

B3 / B4: ?

B5 / B6: ?

A

Pressurizer Heaters:

Bank

Power

Control Power

Capacity

P1:

NGN-L11

NKN-D41

150 kW

P2:

NGN-L12

NKN-D42

150 kW

B1:

PGA-L33

PKA-D21

150 kW

B2:

PGB-L32

PKB-D22

150 kW

B3 / B4:

NGN-L11

NKN-D41

300 kW

B5 / B6:

NGN-L12

NKN-D42

300 kW

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12
Q

Pressurizer Heaters:

?

Backup Heater Controls:

  • ?
A

Pressurizer Heaters:

36 individual heaters (50 KW each / 1800 KW total) – 8 banks

Backup Heater Controls

  • Each backup heater bank has a 3-position switch (OFF, AUTO-ON, PTL)
    • Maintained in AUTO
  • B1 / B2 have an OFF-NORMAL-ON switch on RSP.
  • B2 has a LOCAL - REMOTE isolation switch (App R)
    • LOCAL control at RSP: interlocks and auto features are bypassed.
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13
Q

Backup Heater Setpoint Override:

  • ?
A

Backup Heater Setpoint Override:

  • Allows BU heaters to be energized when > 2225 psia (as long as 2200 psia was reached).
  • Take HS to OFF then to ON.
    • White OVERRIDE light illuminates.
    • After a 10 second time delay, the override can be canceled by taking the HS to OFF.
    • 10 seconds must then elapse before the override can be re-initiated.
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14
Q

Backup Heater SIAS Override (B1/B2 ONLY)

  • ?
A

Backup Heater SIAS Override (B1/B2 ONLY):

  • B1 / B2 trip on SIAS.
  • SIAS Override allows these heater banks to be reenergized with a SIAS present.
  • Initiated by placing HS in OFF, then ON.
    • Separate white OVERRIDE light illuminates.
    • Heater banks can be cycled as desired.
    • Override remains in effect until SIAS signal is reset.
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15
Q

Pressurizer Pressure Controller (PIC-100)

  • ?
  • Red needle – ?
  • Black and white needle - ?
  • Thumbwheel allows adjustment ?
  • Reverse acting?: Raise output to __?\_ pressure
  • Power supply: ?
A

Pressurizer Pressure Controller (PIC-100):

  • Controls proportional heaters and spray valves.
  • 1500-2500 psia
  • Red needle – selected PZR press indication
  • Black and white needle - controller setpoint (thumbwheel)
  • Thumbwheel allows adjustment of controller setpoint.
  • Controlling action only occurs from 0-50%. (Meter range is 0-100%)
    • 16.5% - zero error
    • Pressure error > +50 psi results in controller output increasing from 50% to 100% with no further action.
    • Output normally 16.5% (Heaters makeup for ambient heat loss / spray bypass flow)
  • Reverse acting: Raise output to lower pressure
  • AUTO control can be used to maintain 1500 - 2285 psia.

Power supply: NNN-D12

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16
Q

MPC (0-50% output is the control range):

  • ?
A

MPC (0-50% output is the control range):

  • Raise output to lower pressure
  • 50% - spray full open
  • 33.5% - spray starts / HTRs off / 25 psia above setpoint
  • 16.5% - zero error / HTRs 50% on (normal output)
  • 0% - HTRs full on / 25 psia below setpoint
17
Q

Spray Valve Controller (0-100%):

  • ?
A

Spray Valve Controller (0-100%):

  • Controlled by output of PZR pressure controller in AUTO.
  • Can be operated manually.
  • Spray valves selected by the Spray Valve Selector Switch (100E, Both, 100F) – normally BOTH selected
  • Power supply: NNN-D12
18
Q

PZR Spray Valves (RC-PV-100E / 100F):

  • ​?
A

PZR Spray Valves (RC-PV-100E / 100F):

  • Fail closed AOVs (powered from NNN-D12)
  • Combined spray flow capacity 375 gpm.
  • Design leakage across lower disc (just a slot): ~ .3 gpm
  • Manual bypass valves.
    • Throttled to provide bypass spray flow
    • 1.5 gpm
    • Minimizes thermal shock to the spray nozzle
    • Ensures boron mixing between RCS and PZR
19
Q

Proportional Heater Power Control Units (PPCUs):

  • ?

Proportional Heater Controls (HS-100-1, -2):

  • ?
A

Proportional Heater Power Control Units (PPCUs):

  • Silicon Controlled Rectifier (SCR) control (0 to 480 VAC), balanced 3 phase voltage to one bank of heaters.
  • Controlled by output of PZR pressure controller

Proportional Heater Controls (HS-100-1, -2):

  • Each bank has an OFF-NORMAL-ON hand switch (spring return to normal)
  • ON – heater breaker closes
  • Heater bank power is then controlled by the PPCU from MPC output.
20
Q

PZR Level Transmitter (LT) Failures (Level Controller in “REMOTE/AUTO”):

Selected PZR LT fails low:

  • ?

Non-selected PZR LT fails low:

  • >

Selected PZR LT fails high:

  • ?

Non-selected PZR LT fails high: Alarms only.

A

PZR Level Transmitter (LT) Failures (Level Controller in “REMOTE/AUTO”):

Selected PZR LT fails low:

  • Letdown flow ↓ to minimum
  • “Standby” charging pump starts.
  • Heaters trip if selected to “Both” or failed level channel.
  • Actual LPZR ↑ until the unaffected LT is selected.
  • Select unaffected LT for heater cutout and level control.

Non-selected PZR LT fails low:

  • Heaters will trip on low level (if selected on the heater cutout selector or it’s in BOTH).
  • Select unaffected LT on the heater cutout selector switch.

Selected PZR LT fails high:

  • Letdown flow ↑ to maximum
  • “Normally running” charging pump stops.
  • Possible isolation of letdown due to the auto closure of UV-515 (hi-hi RHX outlet temp due to one charging pump running with max letdown flow). (restart pump to prevent loss of letdown)
  • Backup heaters energize if < 2285 psia due to high level deviation.
  • Actual LPZR ↓ until the unaffected LT is selected.
  • Select unaffected LT.

Non-selected PZR LT fails high: Alarms only.

21
Q

Temperature Transmitter (TT) Failures** **(Level Controller in “REMOTE/AUTO”):

Tcold/Thot fails high (100%):

  • ?

Tcold/Thot fails high (15%):

  • ?

Tcold/Thot fails low (100%):

  • ?

Tcold/Thot fails low (15%):

  • ?
A

Temperature Transmitter (TT) Failures** **(Level Controller in “REMOTE/AUTO”):

Tcold/Thot fails high (100%):

  • High Tave signal sent to PLCS resulting in maximum level setpoint. (no effect, select unaffected Tave)

Tcold/Thot fails high (15%):

  • High Tave signal sent to PLCS resulting in maximum level setpoint.
  • Letdown flow to minimum.
  • Take local control of PLCS and shift Tave to unaffected parameter.

Tcold/Thot fails low (100%):

  • Low Tave results in minimum level setpoint.
    • Tcold failing low (RRS in Average) will result in level setpoint of ~38%
  • Letdown flow to maximum.
  • Normally running charging pump stops (+15% deviation) (not for Tcold failure, only ~14% deviation)
  • Possible isolation of letdown (auto closure of CHB-515 on Hi-Hi RHX outlet temp – max letdown / low charging flow)
  • Energizes backup heaters if < 2285 psia (+3% deviation)
  • Take local control of PLCS and shift Tave to unaffected parameter.

Tcold/Thot fails low (15%):

  • Low Tave signal sent to PLCS resulting in minimum level setpoint. (no effect, select unaffected Tave)
22
Q

PZR Pressure Transmitter (PT) Failures:

Selected PT fails low:

  • ?

Non-selected PT fails high:

  • ?

Selected PT fails high:

  • ?

Non-selected PT fails low:

  • ?
A

PZR Pressure Transmitter (PT) Failures:

Selected PT fails low:

  • MPC goes to Minimum output.
    • Proportional heaters to full output.
    • Spray valves close.
  • All Backup heaters turn on (< 2200 psia).
  • Actual PPZR rises until reactor trip OR operator action
  • Select the unaffected PT

Non-selected PT fails high:

  • PZR trouble and Pressure Hi-Lo annunciators.
  • Turbine Bypass Demand annunciator.
  • SBCS affected:
    • PT-100X - Modulation signal biased downward / controller demand generated.
    • PT-100Y - Permissive signal biased downward / permissive light lit.
  • PZR Pressure control is not affected (alarms only)

Selected PT fails high:

  • PZR trouble and Pressure Hi-Lo annunciators.
  • Turbine Bypass Demand annunciator (due to SBCS impact)
  • SBCS affected:
    • PT-100X - Modulation signal biased downward / controller demand generated.
    • PT-100Y - Permissive signal biased downward / permissive light lit
  • MPC maximum output.
    • Proportional heaters to minimum output.
    • Pressurizer spray valve controller goes to maximum output. Spray valves go full open.
  • All heaters turn off (> 2285 psia)
  • Actual PPZR lowers until reactor trip OR action is taken
  • Select the unaffected PT

Non-selected PT fails low:

  • PZR trouble and Pressure Hi-Lo annunciators only
23
Q

Loss of NNN-D11 (120Vac):

  • ?
A

Loss of NNN-D11 (120Vac):

  • PT-100Y fails LOW (MPC responds, if selected)
  • LT-110Y fails LOW
    • Heaters deenergize if selected to Channel “Y” or “both” (25% level cutout).
  • Normally running and standby Charging Pumps will stop (Manual control available)
  • Select Channel “X” to restore pressure control.
  • Both Letdown Control Valves fail closed. (Letdown isolates)
  • PZR Level Master Controller loses power / fails to zero output.
  • Select Channel ‘X’ to restore PZR heater control.
24
Q

Loss of NNN-D12 (120Vac):

  • ?
A

Loss of NNN-D12 (120Vac):

  • MPC fails to zero output.
  • Spray valves fail closed (no power to spray controller)
  • LT-110X fails LOW
    • Heaters deenergize if selected to Channel “X” or “both” (25% level cutout)
    • LIC output 0% if selected
  • Select channel “Y” to restore heater control.
  • Both Backpressure Control Valves fail closed (loss of power to controller).
  • TIC-223 fails LOW - closing TCV-223 (letdown HX TCV).
  • Loss of power to TS-224-2: CHB-UV-523 (RHX Outlet Isol Valve) closes.
  • Select Channel “Y” to restore PZR level control (Letdown is isolated, only restores control of charging pumps).
25
Q

Loss of NKN-M45 (125 Vdc):

  • Same as loss of NKN-D41 and NKN-D42 combined (see below).

Loss of NKN-D41 (125Vdc):

  • ?

Loss of NKN-D42 (125Vdc):

  • ?
A

Loss of NKN-M45 (125 Vdc):

  • Same as loss of NKN-D41 and NKN-D42 combined (see below).

Loss of NKN-D41 (125Vdc):

  • P1 / B3 / B4 Heater Banks lose control power

Loss of NKN-D42 (125Vdc):

  • PZR Level control bistables lose power
    • PZR level cutout to all heaters (local operation only)
    • LCO 3.0.3 entry is required for class back-up heaters
    • LCO 3.0.3 can be exited once local control established (RSP or at the breakers)
    • All Charging Pumps trip (Manual control is available)
    • PLCS auto circuit lost power
  • P2 / B5 / B6 Heater Banks lose control power
  • PZR Spray VPI is lost.
  • Letdown isolates (loss of power to 63X relay causes 523 to close)
  • Loss of VPI (Letdown Control and Backpressure Control Valves)
26
Q

Loss of PKA-M41 (PKA-D21):

  • ?

Loss of PKB-M42 (PKB-D22):

  • ?

Loss of PNA-D25 (PNB-D26):

  • ?
A

Loss of PKA-M41 (PKA-D21):

  • Spray valves failed closed. (Instrument Air CIV fails closed)
  • One Aux Spray Valve fails closed (RCA-205)
  • B1 loses control power
  • Letdown isolates (Loss of power to CHA-UV-516)

Loss of PKB-M42 (PKB-D22):

  • B2 (backup heater B2) loses control power
  • One Aux Spray Valve fails closed (RCB-203)
  • Letdown isolates (Loss of power to CHB-UV-515 and 523)

Loss of PNA-D25 (PNB-D26):

  • PZR LT-110X (LT-110Y) loses power / fails low.
  • PZR heater breakers open if selected to affected channel or both (25% cutout)
  • Letdown to minimum if selected to affected channel
  • Standby charging pump starts if selected to affected channel (-23% bistable)
  • Select unaffected channel to restore level and heater control
27
Q

LCO 3.4.9 - PZR Operable with

A

LCO 3.4.9 - PZR Operable with

28
Q

TLCO 3.4.100 - Aux Spray Including its basis…

A

TLCO 3.4.100 - Aux Spray Including its basis…

29
Q

TLCO 3.4.102 - PZR HURs/CDRs:

  • Max HUR of 200 *F / hour
  • Max CDR of 200 *F / hour
A

TLCO 3.4.102 - PZR HURs/CDRs:

  • Max HUR of 200 *F / hour
  • Max CDR of 200 *F / hour

.AR LOIT Systems: Welch's Highlighted Notes (60 decks)

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