ED: Extraction Drain Flashcards
Where does Stage #9 extraction steam from the Low Pressure Turbine go?
LPFW Heaters #3 (A,B,C - cross connected)
Gland Steam Supply
What are the operational flowrates associated with the Heater Drain Pump Recirc Valve?
- Opens at 1600 gpm and on a pump stop
- Closes at 3200 gpm
When will Extraction Steam Block Valves re-open if they automatically closed?
They will re-open when the Hi-Hi Level that initiated the closure clears.
How do the BTVs fail on a loss of air?
Closed
How do the High Level Drains on a loss of air or power?
Open on a loss of both
What happens on a Hi-Hi level in a LPFWH?
- LPFWH train isolations close
- BTVs (for #3 and #4) close
- Extraction Steam low point drains open
Where does Stage #5 extraction steam from the High Pressure Turbine go?
HPFW Heaters #6 (A and B)
How do the BTVs fail on a loss of IA?
Closed
To where do the 2nd Stage Drain Tanks A and C vent?
Normally to the #7A HPFWH (via 711A)
Alternate to the Main Condenser (via 711B)
What happens on a Hi-Hi level in a HPFWH (or HDT for 5A/B)?
- All inputs’ Normal Level Control Valves close
- Inputs’ vents swap
- Extraction Steam Block Valve closes
- Bleeder Trip Valve closes
- Extraction Steam low point drain opens
What level in the MSR Drain Tank will trip the Main Turbine?
-3” in the MSR
What valves in the ED System does the 1st Stage Scavenging Mode Selector Switch (EDN-HS-615) control?
It controls the operation of the 1st Stage Drain Tank Vent Valves to the #6 HPFWHs and the Main Condenser.
What are Extraction Steam Block Valves?
Each HPFWH steam line has a motor operated block valve that will:
- for #6/#7 HPFWHs isolate on Hi-Hi level in that HPFWH
- for #5 HPFWHs isolate on Hi-Hi level in its associated HDT
Extraction Steam Block Valves will re-open when the Hi-Hi level clears.
LPFWHs do NOT have Extraction Steam Block Valves.
To where do the HPFWHs vent?
Continuously vented to the Main Condenser. All join to a common header.
What would cause the Feed Water Heater low point drains to auto open?
Turbine Trip
Hi-Hi level in the associated Feed Water Heater
Of course, they can be operated from the Control Room as well.
What is special about the BTV’s on the #7 HPFWHs?
7 HPFWHs BTVs are located upstream of their MOVs. Allows isolation for maintenance while maintaining 1st Stage Reheat in service.
How do the Normal Drains fail on a loss of air or power?
Closed on a loss of both
What are the Heater Drain Pump power supplies?
HDP A - NBN-S02
HDP B - NBN-S01
How do the BTVs and drain valves behave on a Turbine Trip?
- BTVs close (they will reopen once the trip is clear)
- Drain valves open (they will not reclose when the trip clears)
Do LPFWHs have Extraction Steam Block Valves?
No
To where does the MSR Drain Tank vent?
Hot Reheat (discharge from the MSRs)
What is the status of the MSR Drain Tank High Level Control Valve when power is <10%?
It its failed open until Hot Reheat steam pressure reaches a pressure equivalent to ~10%
What is special about HPFW Heater #5?
It has no level control due to being connected to the Heater Drain Tank.
The Normal Level Control Valve for the 1st Stage Drain Tank will auto close on what?
Hi-Hi level in the #6 HPFWH
Where can the 2nd Stage Drain Tank send water?
To the #7 HPFWHs or the Main Condenser
Where does Stage #11 extraction steam from the Low Pressure Turbine go?
LPFW Heaters #2 (A,B,C)
Where is Cold Reheat extraction steam sent?
HPFW Heaters #5 (A and B)
To where do the 2nd Stage Drain Tanks B and D vent?
Normally to the #7B HPFWH (via 712A)
Alternate to the Main Condenser (via 712B)
What happens on a Heater Drain Tank high level?
- Comes in at 9’
- 2 associated MSR Drain Tanks Normal Level Control Valves close
- Associated #6 HPFWH Normal Level Control Valve closes
- Associated #5 BTV and Extraction Steam Block Valve close
Do #1 and #2 LPFWHs have BTVs?
No. They have flow baffles. There’s not enough pressure in these FWHs to warrant protection from a Main Turbine Overspeed.