Reactor Recirc Flashcards
WHat are the RR Motor limitations?
Normal Ops: Current limit of 770Amps
Coast Down: Limit of 800Amps
Motor Winding Temps limited to 248F
What are teh start limitations for RR Pump?
Initial Start (Ambient Temp) 2 successive attempts without time limit
Running for 15 minutes:
1 restart attempt without limit
Running <15 minutes:
Subsequent start requires 45 min cooling period
What are the temp limitations for RR starts?
Temp difference between bottom head coolant and RPV coolant less than or equal to 145F
Temp difference between RR Loop coolant in loop to be started and RPV coolant less than or equal to 50F
What are the limitations for starting second RR Pp?
RR speed is less than 30% for operating pump
Verify temp difference between active and inactive is less than 50 F
What may happen to RPV level when starting RR Pp?
Level may drop up to 6 inches in downcomer region
What is the sequence of events observed when taking RR Pump Control Switch to STart?
Start Signal Ready to Run Light Extinguished Drive ramps to 20% at 5%/second Running Light Lit Drive ramps to 30% at 2.5%/second Raise/Lower Commands locked out until 30% speed reached Increase/Decrease Commands Enabled
Why is RR Pp Discharge Vlv opened slowly after RR Pp started?
To avoid large flow changes and sudden introduction of “cool” water into RPV
Cool water could cause power spiking
When shutting down RR Pp why must FCL be less than 55% PRIRO TO SHUTTING DOWN Pp?
If above 55%, likely to enter unstable region immediately
Why must RR Pp discharge vlv (5A(B)) be in dual indication w/in 2 minutes of Pp Start?
Ensures not dead-headed for long period.
Dead-heading results in axial thrust
Why must seal purge be shut down when shutting down RR Pp?
Do not shutdown prior to shutting down. If it is shutdown, seal purge is the only method of cooling. If RR is isolated from Rx, then isolate seal purge just prior to isolating the loop, otherwise blowout seals
Why is discharge vlv open after pump stops turning?
To maintain idle loop temps
