Exam 2 prep Flashcards
Cberry notes for exam 2
How is level maintained in the PZR?
What are the max and min setpoints when in REMOTE AUTO?
What are the associated Tave values for the max and min Lpzr programs
- Level is maintained between 33%-53% based on Average Coolant Temperature
- Average Coolant Temperature is proportional to Reactor Power
- FAILURES IN TAVG INPUTS EFFECT LEVEL S/P! Not failures of Control Channel Power
- S/P is never below 33% and never above 53% when in REMOTE AUTO
- S/P changes from 33% to 53% linearly from 15%-100% power (Tavg)
- ~ 568F to 586F Tavg (15%-100%)
- Average Coolant Temperature is proportional to Reactor Power
What determines the PLCS setpoints when in Local AUTO?
The operator using the thumbwheel.
What is the AUTO letdown flow limited to by PLCS?
30-135 GPM
State the Lpzr deviation setpoints and what happens at each value.
- +3% all backup heaters on, +2.5% all backup heaters off
- +15% Normal Running CCP goes OFF, +14% Normal Running ON
- -23% Standby CCP turns ON, -14% Standby turn OFF
State the alarms associated with Lpzr and any other associated actions.
- 60% High level alarm (remember Tech Spec @ 56%)
-
25% Low level alarm (Resets @ 27%)
- THIS MATCHES WHEN HEATERS GET LOCKED OUT AND THEN BACK AVAILABLE (ALL HEATERS!)
- Deviation alarms
- +8.5% Hi level alarm in, +8.2% Hi level alarm is clear
- -3.5% Lo level alarm in, -2.7% Lo level alarm is clear
- THESE COME IN BASED ON SETPOINT REMOTE OR LOCAL
How would you determine what the setpoint should be if given a Rx power between 15-100%?
- Given Rx pwr - 15
- Ans/85
- ans*20
- Ans + 33
What happens to Lpzr setpoint on a RCS temp instrument that:
Fails HIGH
Fails LOW
Do temp instrument failures affect Lpzr setpoint in Local/Auto?
High: Lpzr setpoint goes to 53% and PLCS responds.
Low: Lpzr setpoint goes to 33% and PLCS responds.
NO
Actual Lpzr = 33%
Lpzr setpoint is shifted due to failure to 53%.
What happens in PLCS?
Remember:
Actual - Setpoint to get deviation. Do the “does this make sense?” check.
ie. Does it make sense that LD would go to maximum if actual Lpzr is already at the low end of the band? NO.
1. LD flow to minimum
2. STBY CHP DOES NOT START!!!! 33 - 53 = - 20%
3. PZR TRBL
Actual Lpzr = 53%
Lpzr setpoint is shifted due to failure to = 33%
How does PLCS respond?
Remember:
Actual - Setpoint = deviation. Do the “does this make sense?” check.
ie. Does it make sense that LD would go to maximum if actual Lpzr is already at the low end of the band? NO.
Deviation = 20%
- PZR TRBL
- LD flow to maximum
- NORMAL CHP stops
LD will be lost due to HI HI Regen Temp.
- All B/U heaters will energize (if < 2285psia) due to +3% deviation.
What will happen to PZR heaters on a LT-110X failure low if RCN-HS-100-3 is selected to BOTH?
To Y?
All PZR heaters will deenergize on <25% Lvl interlock.
Nothing.
What will occur on a loss of NNN-D11 with respect to Pressure and Level control?
NNN-D11
LIC-110 Master level controller loses pwr = output fails to 0; LCVs fail closed = LD lost
Normal and Stby CHG pps off, manual control available
“Y” level and pressure control channels lose pwr and output fails to 0
“Y” htr cutout channel fails = All htrs off if selected to Both or “Y”
Select channel “X” on HS-110 (level), HS-100-3 (level cutout), and HS-100 (pressure)
What will occur on a loss of NNN-D12 with respect to Level and Press control?
NNN-D12
TS-224-2 pwr loss causes 523 to close = LD lost
TIC-223 fails to 0 causing TV-223 to close
PIC-201 fails to 0 output = BPCVs close = LD lost
PIC-100 Master pressure controller loses pwr = output fails to 0
PIK-100 Spray controller loses pwr = output fails to 0 = spray valves close
“X” level and pressure control channels lose pwr (not LTs/PTs) and output fails to 0
“X” htr cutout channel fails = All htrs off if selected to Both or “X”
Select channel “Y” on HS-110 (level), HS-100-3 (level cutout), and HS-100 (pressure)
What happens to PPCS when the selected PZR press fails low?
- PZR TRBL and PZR PRESS HI - LO
- PPCS master to 0 output.
- Spray valves will close.
- Heaters will energize
- Low Pzr press on B04
What will be the PPCS response to a selected PT that fails HIGH?
- PZR TRBL
- PZR PRESS HI - LO
- Tur Bypass demand alarm
- SBCS affected:
- PT100x - Modulation signal biased down
- PT100y - perm signal biased down.
- Master ctrllr to maximum
- Heaters to OFF
- Spray full OPEN
With no operator action, RCS will trip on LO DNBR.
What will happen to PLCS/PPCS on a loss of NKN-D41?
Alpha train non class heaters will lose control power.
What will happen to PLCS/PPCS on a loss of NKN-D42?
- CHB-523 closes isolating letdown.
- CHP auto control lost => all CHPs stop and are available in manual.
- Loss of position indication: LCV, PCV, main spray.
- PZR lvl control power lost => all htrs off on low lvl.
- can manually operate bkrs
- B train non class htr contrl power lost.
What will happen to PLCS/PPCS on a loss of PKA-M41?
IAA-UV-2 fails closed which will cause a loss of the following:
- LD
- Main spray
- CBO shifts to RDT
Additionally, Aux spray valve 205 fail closed on LOP
AUX SPRAY IS NOT LOST.
Explain what happens on a TC/TH instrument failing HI at 100% power?
TC fails high, 100% power:
High Tave signal sent to PLCS resulting in maximum level setpoint.
No effect, PZR level already at maximum program value.
Operator selects unaffected Tave.
What will happen when a TC/TH instrument fails HIGH at 15 % power?
TC fails high, 15% power:
High Tave signal sent to PLCS resulting in maximum level setpoint.
“Pressurizer Trouble” annunciator alarms.
Letdown flow to minimum.
Operator takes local control of PLCS and shifts Tave to the unaffected
parameter.
What happens if a TC/TH instrument fails low at 100% power?
TC fails low, 100% power:
- Low Tave signal sent to PLCS resulting in minimum level setpoint.
- “Pressurizer Trouble” annunciator alarms.
- Letdown flow to maximum.
- “Normally running” charging pump stops (Tave must be selected to the faulted instrument for a Tcold failure).
- Possible isolation of letdown due to the automatic closure of CHB-UV-515 upon receipt of a hi-hi regenerative heat exchanger outlet temperature.
- B/U heaters energize if < 2285 psia (high pressure cutout for all PZR heaters).
- Operator takes local control of PLCS and shifts Tave to unaffected parameter.
What will happen on a TC/TH instrument failure LOW at 15% power?
TC fails low, 15% power:
- Low Tave signal sent to PLCS resulting in minimum level setpoint.
- No effect, PZR level already at minimum value.
- Operator selects unaffected Tave.
How will a failure of PNA-D25/ PNB-D26 affect PLCS and PPCS?
Panel PNA-D25 (PNB-D26)
PZR level transmitter RCA-LT-110X (RCB-LT-110Y) loses power / fails low.
All PZR heater breakers open if selected to the affected channel or “both” on RCN-HS-100-3.
Letdown to minimum if selected to the affected channel on RCN-HS-110.
Standby charging pump starts if selected to ‘X’ (‘Y’) channel on RCN-HS-110.
Operator will need to select channel ‘Y’ (‘X’) on RCN-HS-110 to restore PZR level control.
Operator will need to select channel ‘Y’ (‘X’) on RCN-HS-100-3 to restore PZR heater control.
What will happen to the PPCS and PLCS system on a loss of NNN-D11?
- LD Ctrl valves fail closed
- PLCS master fails to 0 output
- Normal and STBY CHPs stop. manual is available.
- Operator needs to select CH X on RCN-110, 100-3 and 100 to restore PZR HTR control
- PZR lvl ctrl ch Y fails to 0(buffered signal) - All htrs OFF.
- No output to lvl controller(has no effect - lvl controller has no power).
- RNC PT 100Y fails low. NO htrs due to failed lvl ctrl.
- Operator needs to select CH X to restore press control.
What happens to the PLCS and PPCS on a loss of NNN-D12?
- PCV’s(201P/Q) fail closed due to loss of pwr to ctrlr.
- Loss of LD due to CHB-523 closed
- PZR lvl contrl ch X fails to 0. No heaters if in BOTH or X.
- Must select Y ch on RCS-110 to restore PZR lvl control - only restores control to CHPs.
- Must select Y ch on RCN-100-3 and 100 to restore PZR htr control.
- PPCS master fails to 0 output - full prop heaters signal.
- PZR Spray controller fails - Main SPray lost.
What happens to PLCS/PPCS on a selected PZR level transmitter fail low?
- “Pressurizer Trouble” annunciator.
- “Pressurizer Level Hi-Lo” annunciator.
- Letdown flow decreases to minimum.
- “Standby” charging pump starts.
- Heaters trip if selected to “Both” or failed level channel.
- Actual PZR level increases until the unaffected level channel
is selected. - Operator selects unaffected level channel for heater cutout
and level control. - Low level indication on failed channel (B04).
What happens to PLCS/PPCS on a selected PZR level transmitter fails HIGH?
- “Pressurizer Trouble” annunciator.
- “Pressurizer Level Hi-Lo” annunciator.
- Letdown flow increases to maximum.
- “Normally running” charging pump stops.
- Possible isolation of letdown due to the automatic closure of
CHB-UV-515 upon receipt of a hi-hi regenerative heat exchanger
outlet temperature. - Heaters energize if pressure (< 2285 psia).
- Actual PZR level decreases until the unaffected level channel
is selected. - Operator selects unaffected level channel.
- High level indication on failed channel (B04).
What happens to PPCS/PLCS on a non selected PZR pressure transmitter that fails HIGH?
- “Pressurizer Trouble” annunciator.
- “Pressurizer Pressure Hi-Lo” annunciator.
- “Turbine Bypass Demand” annunicator.
- SBCS affected:
• If PT-100X - Modulation signal biased downward (controller
demand generated).
• If PT-100Y - Permissive signal biased downward (permissive
light lit). - High Pressurizer pressure indication on B04.
- No operator action.
What will happen to INDICATED Lpzr if the Variable leg develops a leak?
the Reference leg develops a leak?
A leak in the variable leg will cause indicated level to LOWER.
A leak in the reference leg will cause indicated level to RISE.
What is the output range on PIC-100 PPCS Master, that will control ONLY THE PROP HEATERS?
SPRAY VALVE?
0% = (full prop heaters) to 33%(prop heaters OFF)
33%(SPRAY begins to open) to 50%(Spray FULL OPEN)
Explain the Setpoint override feature associated with the B/U heaters.
- Every backup heater has Setpoint Override Feature
- This allows energizing backup heaters when PZR Pressure >2225 psia
- Take the handswitch to OFF…….setpoint override light comes on. Then go to ON and the heater should energize
- Setpoint override will remain in for 10 seconds. You cannot remove setpoint override until after 10 seconds.
- When setpoint override is removed, it is locked out for 10 seconds.