RHR Flashcards
What are the RHR pump trips?
- Overcurrent/Overload
- Loadshed
- Lo-Lo RWST (9%) w/ RWST suction not fully closed
What are the interlocks associated with opening IMO-310/320 (RHR Suction from RWST)?
Train specific
- RHR Suction from Recirc (ICM-305/306) Closed
- RHR to Upper Spray (IMO-330/331) Closed
- RHR to CCP/SI Suction (IMO-340/350) Closed
Not on Recirc, RHR Spray or Piggy Backing
What are the interlocks associated with opening IMO-305/306 (Recirc Sump suction valve)?
Train specific
- RHR Suction from RWST (IMO-310/320) Closed
- RWST to CTS (IMO-215/225) Closed
No longer taking suction from RWST for RHR or CTS
What is the interlock associated with opening IMO-128 and ICM-129 (Loop 2 HL RHR suction valve)
RCS pressure < 411 on Loop 1 / Loop 2 WR Press
- (NPS-122 gives signal to IMO-128 from RCS WR Loop 1 Pressure)
- (NPS-121 gives signal to ICM-129 from RCS WR Loop 2 Pressure)
What are the interlocks associated with opening IMO-340/350 (RHR HX to CCP suction)?
Train specific
- RHR Suction from Recirc Sump (ICM-305/306) Open
- SI Recirc to RWST (IMO-262/263) Closed (with Ctrl Pwr on)
Ensures that water cannot be transferred from Recirc Sump to RWST
What are the interlocks associated with IMO-330/331 (RHR spray valves)?
Train Specific
RHR Suction from Recirc Sump (ICM-305/306) open
Must be on Recirc Sump to use RHR Spray & 50 mins after accident
What are the key flows for the RHR pump recirc valve operation?
Unit 1 Opens at 820 gpm and Closes at 1335 gpm
Unit 2 Opens at 900 gpm and Closes at 1500 gpm
What does Hot Leg recirc do for the RCS?
Prevents boron precipitation
What are the pressures that the RHR safety valves lift?
- RHR Suction Safety 450 psig
- Discharge Safeties - 600 psig
- Cooldown Line Safety - 600 psig
When is RHR Spray used?
When there has been a failure of the CTS system
(< 2 CTS pumps are running when required)
What is the Normal Cooldown flowpath for RHR?
Suction fron Loop 2 HL through Hx (IRV-310/320) and Hx Bypass (IRV-311) valves, thru discharge cross ties (IMO-314/324) valves and the out thru ICM-111 to Loop 2 and 3 CLs (Thermal Sleeves)
Preferred flow path when RCS temp > 200°F
What is the ECCS lineup for RHR (Cold Leg Injection)?
- RHR Pumps take suction from RWST through Hx with Discharge crossties IMO-314/324 Open to all 4 Cold Legs
No valves need to re-position
What is the Hot Leg Recirc flow path for RHR?
Injection switched to HLs by opening IMO-315/325 and IMO-316/326 are closed (Must be closed first and SI pumps must be shut off due to recircs being closed)
Where does IRV-300 discharge to and where does it tap off the RHR system??
- Discharges to Inlet of the LD Hx
- Taps off after the RHR Hx before IRV-310/320
What will auto start the RHR Pumps?
Train specific SI
When is RHR placed into service after a Rx Shutdown?
When pressure is ~400 psig and temperature is < 350°F
Why is there a minimum time of 5.5 hours after the accident before doing Hot Leg Recirc?
Avoid core uncovery due to boil off
Why must you close RHR Loop Injection Valves prior to aligning RHR Spray?
Prevents RHR Pumps from running out
In reagards to IMO-128 and ICM-129, ____ valve goes to ____ instrument, which goes to ____ Loop. (insert “Even” and/or “Odd” as applicable)
Even valve goes to even instrument, which goes to odd loop
Or
Odd valve goes to off instrument, which goes to even loop
Can we run BOTH RHR Pumps at reduced inventory?
NO!!
We can only run 1 becaues we could cause air entrainment at Loop 2 suction due to vortexing
On a SI, what does the CCW outlet from the RHR Hx throttle to?
3000-3500 gpm
What is the weak RHR pump is protected by?
RHR Hx discharge check valve (Still has recirc flow)
The following plant conditions exist:
- IMO-320, West RHR Pump Suction - closed
- IMO-390, RHR Pumps Suct from RWST - closed
- IMO-128 and ICM-129, RHR Returns from Hot Leg 2 - open
- ICM-306, Recirc Sump to West RHR/CTS Pumps - closed
- IMO-331, West RHR Spray to Upper Containment - closed
- IMO-350, SI Pump Suction from West RHR Heat Exchanger - closed
- RWST level is 7% and stable
Assuming electrical power is available, IMO-320 _______ be opened because _______.
A. can, IMO-390 & ICM-306 are closed.
B. cannot, RWST level is too low.
C. can, ICM-306, IMO-331 & IMO-350 are closed.
D. cannot, IMO-128 & ICM-129 are open.
C. can, ICM-306, IMO-331 & IMO-350 are closed
While shifting to cold leg recirc during a LOCA, IMO-350, SI Pump Suction from West RHR Hx, will NOT open.
Which ONE of the following conditions must be established to allow IMO-350 to be opened?
A. IMO-361 and IMO-362, SI Pump Suction Cross-Ties to CCP - OPEN
B. IMO-320, West RHR pump Suction - OPEN
C. IMO-262 or IMO-263, SI Pumps Recirc to RWST - CLOSED
D. IMO-261, SI pump Suction From RWST - CLOSED
C. IMO-262 or IMO-263, SI Pumps Recirc to RWST - CLOSED
What does the RHR Suction Safety support?
LTOP
What is the purpose of Hot Sleeve Vent Fans?
Cool concrete to prevent dryout
What is the flowpath for RHR Cold Leg Recirc?
Suction swaps from RWST to Recirc Sump, Discharge cross tie valves IMO-314/324 closed. Going to CL Loops 1-4.
