CVCS Flashcards
CHN-V532 valve type, location, purpose?
AOV, 70 foot aux blg, air isolated open to prevent inadvertently isolating boration flowpaths.
What are the charging pump pulsation dampeners at?
Inlet-19 pounds Discharge-1500 pounds
What is the OE associated with CH-V327?
Was accidentally left closed while swapping charging pump suction to the RWT.
What causes valve 515 to automatically close?
SIAS or High Regen HX outlet temp of 413 degrees F
What causes valve 516 to automatically close?
SIAS or CIAS
What causes valve 523 to close?
CIAS or HIGH LDHX outlet temp of 135 degrees F.
What do valves 515, 516, and 523 do on a loss of power and/or air?
Fail Closed
Where do the letdown pressure relief valves relief to?
Equipment Drain Tank
What is the purpose of the backpressure control valves?
Maintain 350-375 psig upstream of valves to prevent flashing in the LDHX.
Maintain 40-95 psig downstream to prevent component damage.
How do the backpressure control valves fail?
Fail closed. Also close on High LDHX outlet temp of 148 degrees F.
When must we change the purification filters?
When the Delta-P is 25 pounds at 72 gpm or 5R/hr.
What kind of resin is in the deborating IX?
Anion only
What is the location of the VCT?
120’ Aux Building
Where do we get seal water for the charging pumps?
RMW header
How long can we run a charging pump without seal water?
50 hours
What is the motive force for Auxiliary Spray?
Charging pumps. (6.5 gpm with one pump running, 24 gpm with two pumps running)
Where does RCP seal bleedoff go?
VCT
In the event of a containment isolation where does the RCP seal bleedoff go?
RDT via relief valve.
Why is Lithium added to the RCS?
To raise PH
Why do we add Hydrogen Peroxide to the RCS?
Crud Burst to reduce RCS activity to reduce dose
Where do the overflow lines of the RMWT and RWT go?
Holdup tank sump
Where are the BAMPs located?
70 foot aux building
What temperature is maintained at the Boric Acid Batch Tank when batching?
160 degrees F
How do 210X and 210Y fail on a loss of air or power?
Fail Closed
How do we get Boron batched from the Boric acid batch tank?
Acid is transferred to the RWT by an educator. Uses either the RMW pumps or Boric acid makeup pumps flows as a motive force.
What nitrogen pressure is the RDT maintained at?
.5 psig
What is the safety for overpressure protection for the RDT?
Has a 20’’ rupture disc set to blow at 120 psid
Where is the EDT?
Accessed from 40’ Aux Blg through Cooling water hold up tank room. The EDT is a LHRA.
When will the Reactor Drain pumps automatically stop?
Low RDT and EDT when applicable suction is open
What happens to 110P and 110Q on a loss of NKN-D42?
Loss of Indication only.
How does CHE-FV-204 fail on the loss or air or power?
Fails open
What is CHN-UV-511? Where is it?
RMWP recirc. 120 Aux Blg valve gallery near NNN-D16
When will CHN-UV-511 be open or closed?
Closed when flow is >20 gpm
Open when flow is less then 10 gpm
What is CHN-UV-510? Where is it?
BAMP recirc. 120 Aux Blg valve gallery near NNN-D16
When will CHN-UV-510 be open or closed?
Closed when flow is >20 gpm
Open when flow is less then 10 gpm
What is our oxygen concentration limit when adding hydrogen to the VCT?
Do not add hydrogen to the VCT with O2 concentration > 2%.
Coming out of an outage what are the pressure and temperature limits for placing seal injection to the RCPs?
RCS > 215 psia
RCS T> 195 degrees F
What is temperature maintained at in the RWT?
60-120 degrees F
What is the RWT vented to?
Fuel building normal exhaust
Where is the Regen HX located?
100’ of containment behind the elevator
What is CH-UV526?
Letdown control valve bypass valve, Solenoid operated globe valve.
What does CH-UV526 do?
If letdown is isolated for >22 minutes then 526 must be opened for at least 4 minutes prior to initiating letdown in order to minimize the thermal transient on plant components.
What is the purpose of RU-155? Where is it?
Detects possible fuel failure by measuring gross gamma radiation. It is on the 120’ Aux blg near the CEDMCS room.
When is the deborating IX used?
At the end of core life to reduce boron concentration below 30 ppm
What are the three modes of operation for the charging pumps?
Always running mode (red-flagged)
Normal running mode (green-flagged)
Standby mode
Describe each mode of operation for the charging pumps?
Always running mode (red-flagged)-Pump hardstarted, no automatic control actions from PLCS can stop the pump
Normal running mode (green-flagged)- High PZR level will stop pump, when alarm clears pump will restart.
Standby mode- (low level in pzr will start pump and pump will stop when condition clears)
Where is the delay coils? What is it?
100’ containment near RCP 2B. A 2” pipe goes into 2 16” 11.5’ long pipes to give 95 second delay of flow. Decay’s N-16 gammas inside the bioshield
What are some precautions for operating the boric acid batch tank?
- Heat trace operable
- Boric acid solution less than or equal to 12wt%
- Flush BABT and piping after batching
- Don’t energize BABT heaters when water level is below heaters.
- Use RMWP 2x followed by 1x BAMP to maintain 4000 ppm minimum in RWT
How many gallons is 1 1/2 barrels of boric acid?
500 gallons
What indication in the BABT shows that boric acid is completely dissolved?
The water will be clear
What are the low and high points in the VCT?
Low- 5%
High- 60%
How much does one barrel of boric acid weigh?
325 pounds
When it comes to the charging pumps; at what oil pressure do we need to let the control room know?
25 psig
What is the charging pumps seal lube pressure normally?
10-12 psig
At what seal lube pressure on the charging pump will we inform the control room?
less then 5 psig or greater then 19 psig
Where in regards to the charging pumps are we more vigilant with check valve banging?
Charging pump E suction header in the area of CHA-V190
How long does the charging pump seal pump need to run prior to starting a charging pump?
10 minutes
What is our limit to add hydrazine to the RCS?
RCS temp below 250 degrees F
When will the RCP seal injection isolation valve automatically close?
Hi-hi temp- 150 degrees F
lo-lo temp- 70 degrees F
How are 512 and 527 interlocked?
They both cannot be open at the same time
What valve opens when VCT level is reduces to 5%? At what level will it close?
CHN-514
Will close when VCT lo-lo level clears at 15%
If CHN-514 is supplying suction to the charging pumps and it loses power; what valve automatically opens?
CHE-536
How are 501 and 536 interlocked?
They both cannot be opened at the same time
Where do the charging pumps receive power from?
PGA/PGB
When will CHE-520 bypass the IX’s?
At 135 degrees F. Protect the resin
At what flow rate through the IX’s are we concerned with channeling?
150 gpm
Where is the gas stripper bypass valve?
100’ aux building where we can see VCT level.
V655
At what tank pressures do the RDT and EDT auto-isolate?
RDT- 10 psig
EDT- 7 psig
When should we remove a mixed bed IX from service?
- D/P across IX > 20 psid at 72 gpm
- D.F. falls below chemistry requirements
- Letdown temperature exceeds 140 degrees thru IX
- Ionic impurities/ resin fines in effluent
- Resin radioactivity level > 200 R/hr
What would cause CHV-536 to open automatically?
If CHV-514 loses power and VCT is less then 5%
What is the capacity and power supply of the chemical addition pump?
- 25 gph
- NHN
Describe CH-210X.
- Controls flow of RX makeup water
What is the minimum pressure in the VCT?
3 psig
What is the max ambient temperature in the charging pump cubicles?
104 degrees F
What is the design setpoint of CHN-TIC-223?
120 degrees F
What is the concern if we vent the VCT after a hydrogen peroxide add?
We will cause an Oxygen alarm in the GR system.
If we exceed 63 psi in the VCT, what is the concern?
Lifting the charging pump relief valves
What is the makeup to the RMWT?
- RMT
- DW
When will we receive a high level alarm in the RMWT?
39’
At what O2 concentration can we not add H2 to the VCT?
O2> 2%
What was the root cause of the charging pump pulsation dampener failure at Palo Verde?
Discharge dampener bladder failure. The expansion of gas from failure of the elastomer bladder in a discharge pulsation dampener of a standby pump could travel backwards through the pump and gas bind all pumps.
Why does the VCT have two different level instrument types?
226- Dry 227- wet
- On a reference leg leak on 227, LI-227 would indicate a false HI level which would cause letdown to be diverted to the PHIX. LT-226 would see actual level decreasing and would actuate auto VCT makeup at desired set-point for start and stop.
- If LT-226 had water in its dry leg, there would be a false low indication and automatic makeup would be started. Now LT-227 would see actual level.
- There was a modification to provide an alarm on VCT level difference between LT-226 and LT-227. When the difference is 6 inches, LDSH-226 will send a hi level difference alarm input to the VCT trouble alarm window.
What is the recent OE with the CVCS purification bed valve?
Shaft sheared on CHN-V398
What is the large early release factor?
Seen in plant status every morning for risk along with CDF. (Core Damage Frequency).
LERF- Is the ability of the plant to prevent significant releases with the potential for early health impacts on the public (before protective actions can be taken.)
What is EOOS monitor? What does it do?
Equipment out of service monitor. Computerized tool developed for evaluating CDF or LERF risk based on the actual equipment scheduled or deliberately taken out of service for maintenance, testing and repair.
What are the relief valves on the charging pumps suction and discharge set to? Where do they go?
suction- 200 psig goes to EDT
discharge- 2735 psig goes to EDT
How many boration flow paths are required to be available?
At least 2 of the following;
- Gravity feed from either the RWT or SFP thru CH-536
- Gravity feed from RWT through CH-327
- RWT or SFP thru CH-164
