Reactor Coolant System Flashcards
What is core bypass flow for?
prevent stagnant areas of water and keeps water in the head below Tsat.
What is our normal RCS pressure?
2250 PSIA
What is our cold leg temp?
557 degrees F
What is our hot leg temp?
617 degrees F
What is the motive force for main spray?
RCP’s
What is the Steam generator separates the primary and secondary side?
Tube sheet and U-tubes
What normally provides heat removal for the RCS system?
Main Steam and FW
Where can the primary sampling system get a sample from?
Loop 1 hot leg, surge line, pressurizer steam space
What are the three types of CEA’s?
Regulating, part strength, and shutdown
How many CEA’s are there?
89
What is the 4 spring-loaded pressurizer safety valves setpoint?
2750 psia
Why is a fuel rod pressurized with helium
Preclude clad collapse
Improve thermal conductivity
Describe the construction of a typical fuel rod
Slightly enriched UO2 pellet
Round wire compression spring
Spacer discs at each end of the fuel column
Where do the pressurizer over-pressure relief valves go to on an overpressure?
Reactor Drain Tank
What cools the RCP’s?
NCW
What does NCW cool on the RCP’s?
- RCP motor air cooler
- RCP motor lube oil cooler
- RCP thrust bearing oil cooler
- RCP seal coolers
How many regulating groups are there and how are they designated?
five groups
1,2,3,4,5
What components makeup a fuel assembly?
Fuel spacer grids, upper end fitting, hold down plate, lower end fitting, guide tubes, fuel rods
Describe a fuel rod?
U02 pellets
Round wire SS compression spring with a spacer disc located at each end of the fuel column all encapsulated in a seal welded tube and pressurized with helium
What components makeup a steam generator?
Primary chamber tube sheet and u-tubes secondary side shell feedwater ring economizer wrapper plate moisture separators steam dryers
How is oil supplied during normal RCP operation?
Impeller that is keyed to the main drive shaft assy of the pump.
Will the lift pump start in auto if the RCP trips?
No, the operator must start the pump. There is no auto start, only the auto stop after 2 minutes of the RCP running
What are the three fission barriers?
Fuel Cladding
Reactor Coolant Boundary
Containment
How do we regulate RCS pressure?
Pressurizer heaters and Main Spray
Pzr Heaters- (36 of them) Boil water to increase mass of steam in vapor space.
Main Spray- Condense steam in vapor space with subcooled water.
How do we regulate pressurizer level?
PZR level control system
Explain the main spray valves?
- 100E/F
- Start to open- 2275 psia
- Full open - 2300 psia
Describe the pressurizer?
- Acts as a surge volume to minimize pressure changes
- Ensures primary system integrity by preventing over pressurization
- Maintains RCS subcooled
How is main spray bypass flow rate controlled?
Bypass valves around the main spray bypass valves. Manually adjusted to achieve a flow rate to establish a delta-T between the CL and spray nozzle of the PZR of 70 degrees F.
What does IA supply air to in the RCS system?
- Pzr spray valves
- Controlled bleedoff containment iso valves
- Bleedoff isolation to RDT
What are the starting permissives for a RCP?
No motor faults
Oil lift flow sufficient
NCW flow sufficient
RCP seal bleedoff valve fully open
RCP automatic trips
Undervoltage
Coastdown
Overcurrent
Speed less then 600 RPM 14 seconds after start
Describe the flow path of seal injection through RCP shaft seal assembly.
- 6.6 gpm from CVCS enters HP piping thru jet pump
- mixes with 16 gpm from lower journal bearing
- 22.6 gpm flows thru HP cooler
- Splits. 20 gpm to aux impeller thru journal bearings
- Of that 20 gpm, 16 gpm goes back to jet pump
- Of that 20 gpm, 4 gpm goes to the RCS
- 2.6 of the 22.6 gpm flows thru labyrinth seals
- 3 stages (42%/42%/16%)
- Most flow back to VCT (of the 2.6 gpm)
- Any leakage past vapor seal to RDT
