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
What colors are the overspeed lights in the Control Room and the RSP?
Control Room - White
RSP - Blue
Local - Blue
How do you reset AFA-HV-54?
Ensure 134/138/54 are closed. Align latch lever and trip hook locally. Open 54 from the Control Room.
What lights do you get in the Control Room on a mechanical trip of AFA?
Both green lights for the AFA-HV-54 switch will be lit along with the white overspeed light.
What lights do you get in the Control Room on an Electrical/Pushbutton trip?
Upper green light (for valve position) and lower red light (for motor actuator status)
How do you reset AFA-HV-54 after an Electrical/Pushbutton trip?
Check 134/138 closed. Close 54 until two green lights. Open 54 until two red lights. No AO actions.
How does a blown control power fuse affect AFA from the Control Room?
Removes remote trip capability and 54 operability from the Control Room
What will automatically start AFB?
AFAS
SIAS
CSAS
LOP
What is the amp limit for AFB?
151 amps
What are the time delays for automatic AFB pump starts?
AFAS starts immediately
All others - 10 seconds
If AFB is running, what happens if it receives one of its safety signals?
AFB will continue to run on all signals except a LOP (it’ll stop and then get sequenced on)
What auto actions are available for AFB if the Local/Remote switch is in LOCAL?
No auto actions or remote control is available.
Where is AFN RMWT suction valve?
It doesn’t have one.
Describe the AFN suction line.
2 MOV’s (1 and 4) from the CST (normally closed). Switches available on B06.
What are the power supplies to CTA-UV-1/4?
PHA
What requirement must be met before AFN can be started?
CTA-UV-1 and CTA-UV-4 must be >80% open.
What will cause AFN to trip?
- CTA-UV-1 and CTA-UV-4 <80% open.
- A Train SIAS (can be overridden)
- Undervoltage on PBA-S03
Where does AFN tap into the SG System?
Upstream of the Downcomer Control Valves
When feeding the SGs with AFN during shutdown conditions, how is this normally accomplished and why?
Manually through the Downcomer Control Valve Bypass. Needs to be done manually because the amount of feed needed while shutdown is small and the automatic system tends to overfill the SGs.
When do the Downcomer lines become voided?
<27% Narrow Range
If the Downcomer lines become voided, what operational restriction do we impose to prevent water hammer?
A feed rate of >250 gpm or damage to the feed ring may occur. Once >27%NR, any feed rate is acceptable.
What happens to AFN on a MSIS? How do we deal with this.
It becomes unavailable because its upstream of the FWIVs. We override the Downcomer Isolation Valves to provide a feed path.
What is special about the control power for AFN?
Has two supplies: a normal supply from PKA-D21 and an alternate supply from the A Battery Charger.
What is the amp limit for AFN?
122 amps
When does an AFAS actuate?
25.8% Wide Range
What happens on an AFAS?
- AFA and AFB start
- Both DGs start
- Both trains of SP, EC, and EW start
- All SGBD and sampling isolates
- All A and B AF valves open for affected Msgs
An AFAS was actuated manually and the switches were put back to normal. How will the valves operate?
Valves will close until 25.8% and then reopen until 40.8%.
An AFAS was actuated manually and the switches were not put back to normal. How will the valves operate?
Valves will stay open and remain open when SGWL reaches 40.8%.
What will actuate a DAFAS?
SPS actuation on high pressurizer pressure (2409 psia), 20.3%WR SGWL, no AFAS present, and no MSIS present.
What is the capacity of the CST?
550,000 gallons
How much water inventory is reserved in the CST for Aux Feed?
300,000 gallons (25’)
140,000 for 8 hrs of hot stby
140,000 for cooldown to 350F
What is the TechSpec limit for CST level?
29.5’
What is the makeup source for the CST?
Demineralized Water
How much water inventory is reserved in the RMWT for Aux Feed?
300,000 gallons
If AF is aligned to the RMWT, what is the concern?
Recirc of the AF pumps is still going to the CST and could contaminate the CST.
How do the Essential ACU’s for AF operate?
They start automatically on an automatic pump start. They’ll run for 5 minutes after the pump is secured. (“A” starts if either MOV is opened)
Do EC and EW start if an AF pump is started manually?
No. They must be started manually as well.
What is the basis for the Essential ACU’s for AF?
To maintain the rooms <104F.
What is the automatic feature associated with the AF room dampers?
If level in the room reaches 3’6” the dampers will close to keep from flooding both rooms.
How does a loss of PKA-M41/D21 affect the AF System?
- Lose AFA govorner control power; AFA trips on overspeed if running.
- 134/138 and 134A/138A fail as-is.
- AFA flow valves fail as-is.
- AFN loses control power; swap to ‘A’ Battery Charger
How does a loss of PKB-M42/D22 affect the AF System?
- AFB loses control power
- Downcomer isolation valves fail open and lose position indication; AFN can feed SGs
How do the Downcomer Isolation Valves fail on a loss of power? Air?
Open.
Closed (once you lose all N2 as well).
Allows for feeding the SGs with AFN.
What happens on an AFAS-1?
For #1 SG
Both AFA and AFB will start and feed #1 SG to between 25.8% and 40.8%
What indications for AFA-54 are required in the Control Room to consider it in standby?
Both red lights
Will AFB start on a CIAS?
No
What does PKA-M41 supply to AFA?
Governor Control Power
How do the AFA steam supply valves behave on an AFAS?
They both open
What does PKA-M41 supply for AFN?
Normal Control Power
