AF: Auxiliary Feed Flashcards
What is the basis for the AF System?
Maintains Hot Standby for 8 hours and then cool down to 350F at 75F/hour with a LOOP.
What type of pump is AFA?
An 8 stage double volute pump (reduces radial forces)
Up to what power can an AF Pump be used to feed the SG’s?
~ 3%
Main Feed is typically used above 2%.
What will cause AFA to auto start?
AFAS only
What are the design characteristics of AFA and AFB?
750 gpm at 1270 psia
To where do all three AF pumps recirculation travel?
The CST. Cannot be aligned to the RMWT.
What is the RPM requirement for proper lubrications for AFA?
1000 RPM
What cools AFA oil?
AFA - a slip stream from the first stage is directed to the LO cooler.
How long can AFA run with RPM less than 1000 RPM?
5 minutes.
What is AFA minimum idle speed?
800 RPM
What is Aux Steam used for in regards to AFA?
Overspeed Testing (aligned manually)
At what RPM (about) is AFA set to run?
3600 RPM
At what RPM will AFA overspeed?
4058 +/- 50 RPM
Where are the potentiometers for AFA?
One on B06
One on the pump
One on the RSP
What are the AFA potentiometers set to by default?
3600 RPM
From where can the speed reference signal for AFA come?
A ramp generator signal converter (RGSC) or from one of the three (3) potentiometers.
Where do AFA and AFB tap into to feed the Steam Generators?
In the Downcomer Line past the last check valve in Containment.
What is the normal source of steam for AFA?
Main Steam
What differential pressure will lock out a Steam Generator from being fed by Auxiliary Feed?
185 psid
The SG with the low pressure is locked out.
What valves are affected by the D/P Lockout?
Feed valves to the SGs. Steam supply valves are NOT affected.
What is the power supply to 134 and 138?
PKA
PKA-M41
How do you override 134 and 138?
Take control switches to OPEN (their actuated position) and then to CLOSE
Describe 134A and 138A.
1” motor operated bypass valves around 134 and 138
How do 134A and 138A operate when called?
- Open 30 seconds prior to 134 and 138 (~6 seconds to stroke)
- Close automatically when 134 and 138 are called to close.
- No time delay when closed from the Control Room.
Why do 134 and 138 have bypass valves?
Allows the Terry Turbine to gain sufficient speed to raise governor oil pressure. Prevents the initial admission of steam from overspeedof the turbine
Why do we continuously drain condensate from the steam lines to AFA?
To prevent an overspeed on initial start up.
Describe AFA-HV-54
A trip/throttle valve that has a motor for throttling and a spring for tripping.
From where can you operate AFA-HV-54?
Locally, B06, and the RSP
In what position is AFA-HV-54 normally?
Open
What purpose does AFA-HV-54 serve for AFA?
Serves as the steam securing mechanism on a turbine overspeed