C11 - CRD Flashcards
How much flow maintained in the CRD flow control station?
60 gpm
How much flow is allowed through the flow control valve in the closed position due to mechanical stop?
5 gpm
How does flow control valve react to changes in flow?
> 60 gpm valve closed
< 60 gpm valve opens
What powers ARI?
E and K
What powers the SCRAM valves?
RPS A and B
Where are the CRD pumps controlled from?
601 panel and remote shutdown panels
What’s the CRD pump trips?
> 6.4” Hg low suction pressure (approx 20’ in the CST)
< 3.0 low oil pressure
ESF load shed
MPD
What’s the purpose of the pressure control valve?
maintain drive water pressure 250 psig above Rx pressure
Maintain cooling water pressure < 20 psig about Rx pressure
What can high cooling water pressure cause?
Control rod drive
What will excessive drive water pressure cause?
internal damage to CRD drive mechanism
When does Aux oil pumps start for CRD?
3-5 psig AND pump breaker open
When does Aux oil pump trip?
10 psig
What’s the purpose of equalizing valves?
Prevents large DP on CRD piston
What does the SCRAM air header supply?
Air to SCRAM valves and SCRAM discharge volume (SDV) vent and drain valves, vents air on SCRAM signal
What pressures are HCUs charged to?
1250 psig water
1775 psig water/nitrogen
What’s the purpose of SCRAM discharge volume (SDV)?
collects water from CRD mechs during SCRAM. it’s normally empty (drains to suppression pool)
how many stab valves close to insert and withdraw a control ROD?
Insert - 2 valves close
withdraw - 2 valves close at first (to lift off collet fingers) then 1 valve for withdraw
How much flow is required for the process of inserting and withdrawing a control rod (stab valves)
Insert 5.2 gpm
withdraw 4.2 gpm
What is the tech spec time for inserting a control rod?
7 seconds
when does the alarm come in for HCU pressure?
1600 psig
What is the tech spec limit for HCU pressure?
1520 psig
What is the alarm, rod block, and SCRAM setpoints for SDV?
Alarm 2.5” 3 gallons
Rod block 32” 13 gallons
SCRAM 64” 26 gallons
What’s the purpose of collet fingers?
prevents rod drift, prevents rod from moving downward, allows for incremental adjustments
What’s the purpose of the ball-check valve in CRD system?
Allows Rx pressure to SCRAM Rx with loss of CRD pressure used in HCU failure
What’s the purpose of the velocity limiter?
Reduced fall rate to 5 ft/s in Rod drop accident to protect fuel (excessive reactivity)
What’s the coupling spud?
connects rod to mech
What slows down the rod after a SCRAM?
Buffer piston
What happens if under piston line breaks?
Nothing (Collet fingers hold it in place)
What happens if over piston (P-over) ruptures?
Rod inserts with cooling water (control rod drift)
