Heater Bleeds And Drains(HAW) Flashcards
What is the purpose of the Heater Bleeds and Drains System?
Increase cycle efficiency by pre-heating condensate/feedwater with the extraction steam supplied from various stages of the high pressure and low pressure turbines
What is the system designator for the Heater Bleeds and Drains System?
HAW
What is the design/purpose of the Extraction Line Check Valves?
- Installed on the Extraction Steam lines to the A-E Heaters
- Quickly isolate the turbine from the heater shells following a turbine trip to prevent overspeed if the energy was to backflow from the heaters to the turbine
- Spring assisted closed, fully closed by reverse flow
When do the Extraction Line Check Valves automatically close?
- Turbine trip
- Emergency High level(2nd level switch)
- Loss of air
- Loss of power to solenoid supplying air
Where do all of the Extraction Steam line drain valves drain to?
The condenser
What is the purpose of the Before Extraction Check Valve Drain Valves?
These valves open to drain water preventing water hammer and water introduction.
What will cause the Before Extraction Check Valve Drain Valves to open and close?
- The valves are manually closed during turbine warmup
- The valves will automatically open on:
A. Turbine trip
OR
B. Less than 15% turbine load as sensed by impulse pressure
OR
C. Emergency high level in the associated heater
What is the purpose of the Continuous Drain Orifice downstream of the Extraction Line Check Valve?
Continuously drains moisture from the line to the condenser to prevent water hammer and water introduction
What will cause the Continuous Drain Orifice Bypass Valve to automatically open?
The valves will automatically open on:
A. Turbine trip
OR
B. Less than 15% turbine load as sensed by impulse pressure
OR
C. High level in the drain line(1st level switch)
What is the purpose of the Extraction Line Isolation Before Seat Drain Valves?
Prevent water hammer when initiating Extraction Steam flow
What will cause the Extraction Line Isolation Before Seat Drain Valves to open or close?
- Automatically open on:
A. Turbine trip
OR
B. Less than 15% load as sensed by turbine impulse pressure - Automatically close when “Shell Warming” is selected, and automatically open when “Shell Warming” is deselected
What will cause the Heater Inlet Steam Isolation Valve to automatically close, and what is unique about the automatic closure signal?
- Automatically closes on Emergency High Level in the associate heater.
- The Heater Inlet Isolation Valves are throttle valves so to open and close them the Pushbuttons must be held
- The closure signal is only present when the Emergency High level is present. If the condition clears while the valve is stroking it will stop at some intermediate position
What will cause the Heater Inlet Steam Bypass Valve to automatically close?
Emergency High level in the associated heater
What heaters have a Heater Inlet Steam Isolation Valve and Bypass Valve?
The ‘A’ and ‘B’ Heaters are the only heaters that have this configuration
Where are all of the Heater Vents directed to?
The condenser
at 85% load most of the vents are closed
What does ‘A’ Bleed supply and when?
‘A’ Bleed supplies the MSR first stage heating steam above 10% load
What does ‘C’ Bleed supply, and when?
‘C’ Bleed begins supplying the Auxiliary Steam header between 15% and 20%
What does ‘E’ Bleed supply, and when?
‘E’ Bleed supplies the Main Turbine and CFPT Steam Seals when greater than 60%
What are the inputs to ‘A’ Heater shells?
- MSR Second Stage Drain Tank drains
- MSR Second Stage Reheater Scavenging Steam
- ‘A’ Bleed Steam
Where does each MSR Second Stage Reheater Drain Tank drain go?
- A and B Second Stage Reheater Drain Tank drains go to the A2 Heater
- C and D Second Stage Reheater Drain Tank drains go to the A1 Heater
What automatic actions occur on an ‘A’ Heater Emergency High Level?
- Closes the Extraction Steam Line Isolation and Bypass Valve to the ‘A’ Heater
- Isolates the inputs from the MSR Second Stage Drain Tank and Scavenging Steam
- Closes the ‘A’ Heater Normal Drain Valve
- Opens the Before Extraction Check Valve Drain on the Extraction Steam line
What are the inputs ‘B’ Heater Shells?
- MSR First Stage Drain Tank drains and Scavenging Steam
- ‘A’ Heater normal drains
- ‘B’ Bleed Steam
Where does each MSR First Stage Reheater Drain Tank drain go?
- A and B First Stage Reheater Drain Tank drains to the B2 Heater
- C and D First Stage Reheater Drain Tank drains to the B1 Heater
What actions occur on an Emergency High Level in the ‘B’ Heaters?
- Closes the Extraction Line Isolation and Bypass Valves
- Isolates the inputs from the MSR First Stage Drain Tank and Scavenging Steam
- Closes the ‘A’ Heater input drain
- Closes the ‘B’ Heater Normal Drain Valve
- Opens the Before Extraction Check Valve Drain on the Extraction Steam line
What is unique about the ‘C’ Heater?
The ‘C’ Heater is a “dry” heater
What are the inputs into the ‘C’ Heater Drain Tank?
- MSR Moisture Separator Drain Tanks
- ‘B’ Heater drains
- ‘C’ Heater drains
- ‘C’ Heater Drain Tank Pumps discharge vents
- Main Feed Pump seal leakoff
- ‘C’ Heater Drain Tank Pump discharge recirculation
What actions occur on an Emergency High Level in the ‘C’ Heater Drain Tank?
- Opens the Before Extraction Check Valve Drain
- Closes the ‘C’ Heater Extraction Line Isolation
- Closes the ‘B’ Heater Normal Drain Valve
- Closes the MSR Moisture Separator Drain Tank input
- Closes the Main Feed Pump Seal Leakoff input
When are the ‘C’ Heater Drain Tank Pumps placed in service, and how much flow do they contribute?
- Placed in service at 70% power and removed prior to going below 70% power
- Provide 32% of feed flow at 100% load
What provides cooling water the ‘C’ Heater Drain Tank Pumps?
The Recirculate Cooling System(KR) provides cooling to:
- Mechanical Seal Coolers
- Seal Injection Water Coolers
- Motor Bearings
What will cause the ‘C’ Heater Drain Tank Pumps to automatically trip?
- Turbine trip
- Emergency low level in the ‘C’ Heater Drain Tank
- Full load rejection greater than 56% power
What are the inputs into the ‘D’ Heater Shells?
- ‘D’ Bleed Steam
2. Steam Generator Blowdown Heat Exchanger(BB) Vent
What actions occur on an Emergency High Level in the ‘D’ Heaters?
- Closes the ‘D’ Heater Extraction Line Isolation
- Closes the ‘D’ Heater Normal Drain Valve
- Closes the BB Vent to the ‘D’ Heater
- Opens the Before Extraction Check Valve drain on the extraction lines
What are the inputs to the ‘E’ Heater Shells?
- ‘E’ Bleed Steam
2. ‘D’ Heater Drains
What actions occur on an Emergency High Level in the ‘E’ Heaters?
- Closes the ‘E’ Heater Extraction Line Isolation
- Closes the ‘D’ Normal Drain Valve
- Closes the ‘E’ Normal Drain Valve
- Opens the Before Extraction Check Valve Drain on the Extraction Steam line
What are the inputs into the ‘F’ Heater Shells?
- ‘E’ Heater Drains
2. ‘F’ Bleed Steam
What actions occur on an Emergency High Level in the ‘F’ Heaters?
- Opens the condensate bypass valve CM-81
- Closes the ‘E’ Heater Drain Valves
- Closes the condensate tube side isolation valves
* There are no isolation or drain valves in the Extraction Steam line, also the ‘F’ Drains to ‘G’ Heaters does not get closed*
What are the inputs to the ‘G’ Heater Shells?
- ‘F’ Heater Drains
2. ‘G’ Bleed Steam
What actions occur on an Emergency High Level in the ‘G’ Heaters?
- Opens the condensate bypass valve CM-81
- Closes the ‘F’ Heater Drain Valves
- Closes the condensate tube side isolation valves
* There are no isolation or drain valves in the Extraction Steam line*
How are the drains controlled from the ‘E’ Heaters to the ‘F’ Heaters?
A proportional controller ensures that each ‘F’ Heater receives 2/3 of the drains from the ‘E’ Heaters
What is the normal operating level for Heaters on Narrow and Wide Range level instruments?
- Narrow Range - 0 inches
- Narrow Range of 0 inches corresponds to a Wide Range level of 9% to 17%
- ‘F’ and ‘G’ Heaters have a normal Wide Range level of 50%
How is the Auto/Manual Controller for Heaters adjusted?
Automatic:
- In automatic, the setpoint(red needle) is controlled by the potentiometer labeled “SET”, varying the setpoint initiates a valve position demand
- As actual valve position changes, the actual level(black needle) will change as well
Manual: In manual, the setpoint adjustment is not functional. The “VALVE” pot is used to directly vary valve position demand. The setpoint(red needle) will follow the actual level(black needle) to allow for a bumpless transfer to automatic
What is important to remember when adjusting Heater level controllers?
Adjusting level in the Heaters is reactivity management related because it can have impact on core reactivity by changing feedwater inlet temperature
What are the power supplies for the ‘C’ Heater Drain Tank Pumps?
1(2)C1 - 1(2)TC
1(2)C2 - 1(2)TD
What happens in each Heater as on a High level before reaching the Emergency High level?
An alternate drain will open dumping water to the condenser to attempt to lower level
