Condensate Flashcards
Where does main condenser collects from ?
-Main Turbine Exhaust Steam
-MFWP Exhaust Steam
-Extraction Steam Drains from LPFW Heaters
-Other equipment
How is each condenser section divided into two halves ?
1A,2A
1A,2B
1C,2C
What helps maintain vacuum in the condenser shells ?
Established & maintained by both Condenser Air Removal & condensing action of exhaust steam
What is the vacuum in each condenser shell?
A shell: 1.5 - 2.5HgA
B shell: 2.0 - 2.5HgA
C Shell: 2.8 - 4.3HgA
Why do the tube bundles in each condenser shell get longer ?
Longer in each shell because circulating water gets warmer as it goes through each shell
Where are the AR system installed for each tube bundle ?
AR system installed in middle of each tube bundle
Why is AR system installed in middle of each tube bundle ?
-Minimize condenser pressure & maximize turbine efficiency
-Minimize oxygen concentration in condensate to prevent oxygen from reaching Steam Generator
What’re the Main Condenser Expansion Joints used for ?
-Connects each condenser shell to LP Turbine
-Prevents air leakage into condenser while allowing movement between Turbine Casing & Condenser Sections
Each Main Condenser Expansion Joint has a trough around seal, why would we fill it with water ?
Normally kept dry, but could be filled water if joint seal has hole water will be drawn into condenser instead of air
What water is used to fill the Expansion Joint Seal trough ?
Filled with Condensate Service Header if there’s a hole in joint seal
If water is introduced to trough, why is important to keep it maintained ?
If trough is drained out than it could cause neoprene seal to crack
How is water level maintained in the Expansion Joint Seal trough ?
Maintained by locking makeup valve in throttled position to provide trickle of water to trough
What’re the Main Condenser Equalization Ducts used for?
Protects condenser from damage due to high DP
Where does the condenser equalizing receive its seal water from?
Seal water provided from Condensate Service Header
How do the Condenser Equalizing Ducts work ?
-Allows pressure equalization if pressure DP rises between shell
-Water seal will blow out if temperature difference is 30F
How can you indicate level inside the Condenser Equalizing Ducts ?
There is a local sight glass to monitor level
What’re the Main Condenser Vacuum Breakers used for ?
Installed each condenser section,allows rapid Main Turbine slowing down under normal & emergency conditions
Why is the Vacuum Break Line filled with water? What water is used ?
-Filled with water from Condensate Service Header
-Water ensures any leakage past valve will draw water instead of air into condenser
What does the Vacuum Break Line have on the atmosphere side to prevent debris from entering line ?
There is a conical screen to prevent debris from entering
What does the inner bottom sump do ?
They collect condensate from each half of the condenser shell which is done by a divider plate
What does the divider plate that separates each shell half allow us to do during condenser tube rupture ?
It’ll allow us to isolate main condenser half upon a tube leak
What does the water in the inner bottom sump provide ?
Forms water seal between LP in shell & HP in hotwell
What do the perforated plates at the bottom of inner bottom dumps do ?
Breaks up water & fall more slowly through reheat section
Where does the MFWPT direct it’s exhaust to ?
Exhaust directed to A reheat trays, then through hotwell equalization ducts to B reheat trays , then exhaust goes into C condenser and condenses since there no reheat trays
Which condenser shell pressure are the three hot wells at ?
Since there is no inner bottom sump in ‘C’ Condenser shell, then all hotwells are at ‘C’ Main Condenser
How do we indicate reheat tray level ?
Reheat Tray level sight glass is installed on A & B Condenser halves
How do we collect condensate samples from hotwell?
Allows chemically contaminated condensate to be detected when it enters hotwell
What does the salinity detection cabinet provide for the condenser chemistry ?
Provided required detention time to close circ water valves, & isolate hotwell halves to prevent chemically contaminated water from reaching steam generators
What does condensate sparging do ?
Hotwells can use Aux. Steam directly into Hotwell Reheat Section to preheat condensate secondary plant startup
What power level do we have to reduce to when there is a Main Condenser tube rupture ?
40% power level
How many gallons is maintained in the Main Condenser Hotwells ?
100,000 gallons of condensate storage & volume
What will automatically close the both hotwell makeup valves ?
Both valves are interlocked to close on a CST LO-LO LVL
Where is hotwell draw off taking water from ?
Takes water from the discharge of the condensate pump & directs to CST
When will the Hotwell level draw off valve close ?
-Closes on low suction pressure from Main FW Pump
-Closes on high conductivity in condenser hotwell
If the hotwell drawoff valves closes due to high conductivity, how do you reset the valve ?
Valve must be reset locally by a placing key locked bypass switch to bypass position
What else if the hotwell draw off bypass used for ?
Used to drain hotwells to CST during outage
What do the condensate pumps do ?
Takes condensate from hotwells & send it through LPFWH to the two MFWP
What is the capacity of each Condensate Pump ? What is the discharge pressure for the pump ?
50% capacity & discharge pressure or 450psig
Where does ‘A’ Condensate Pump take suction from ?
Takes suction from 2 A,B,& C
Where does ‘C’ condensate pump take suction from ?
Takes suction from 1A,B, & C
Where can the normal & abnormal lineup for the ‘B’ Condensate Pump since it has to suction valves ?
-Normal line up can take suction from both hotwell halves
-Abnormal lineup can take suction from either half of hotwells
How many Condensate Pumps are normally running ?
All three are normally running
Where does the Condensate Pump Shaft receive its seal water from ?
Receives water from Condensate Service Header to cool & seal shaft packing
How does the seal water going to the condensate pump work ?
Seal water comes up into pump bowl & overflows via drain line to floor sump
What cools the Condensate Pump Motor Upper Bearings ? What is used to cool the oil ?
Lubricated with oil, which is cooled by turbine cooling water
What cools the condensate pump lower motor bearings ?
They’re grease lubricated
Why does each condensate pump have a space heater ?
Auto turns on when condensate pump is stopped to protect pumps motor from condensation
What do the white lights on the CD Pump MCC indicate ?
It indicates space heaters are energized
What flowrate do the automatic flow control valves maintain in the CD Pump Recirc lines ?
Recirc lines had to maintain at least 4500gpm
Which valve is interlocked with the CD Pump Recirc line flow control
Valve ?
Interlocked with pump suction valves, when suction valve closes Recirc valves will close
What is difference about the ‘B’ Condensate Pump Recirc lines ?
Recirc lines has two Recirc valves along with two suction valves
What’re the Condensate Pump power supplies ?
‘A’ CD Pump:NBN-S01
‘B’ CD Pump:NBN-S01
‘C’ CD Pump:NBN-S02
What will trip the Condensate Pumps ?
-Any CD pump trips if aligned hotwell drops to 30”
-Will trip low flow 36,000gpm following 45 second time delay
How could the suction valves for the ‘B’ CD Pump trip the pump ?
-Will trip if both of suction valves come off their fully open seat
-One suction valve must be fully open
What do the two overboard valves do?
Directs condensate pump ‘A’ & ‘C’ discharge to the circ water canal
When are the Overboad valves used?
-When CST is full & can’t accept drawoff
-When CST temp is to high
-During main condenser tube leak to discharge hotwell contents
-During secondary plant startup for secondary chemistry control
When are the overboard valves most commonly used for ? Where are they operated from ?
-Commonly used for feed& bleed to remove impurities during plant startup
What pressure is the condensate service header reduced to?
Reduced to 50-100psig usually maintained high in pressure band
What supplies Condensate Service Header when condensate Pump Discharge isn’t available?
DW can be supplied by a MOV
What’re the major loads on Condensate Service Header ?
-CD Pump shaft seal water
-HTR Drain Pump shaft seal water
-Main Condenser expansion joints
-Vacuum breaker makeup water
-Condenser AR Vacuum pump seal water
-Hydrazine & ammonia tank dilution water
What is the temperate difference is between #1LPFWH & the #4LPFWH?
Water is 120F entering #1LPFWH & 340F exiting the #4LPFWH
What happens to inlet & outlet valves of each train of LPFWH, if one receives a HI-HI LVL ?
If LPFWH receives a HI-HI LVL then that string of heaters inlet & outlet valves will automatically close
Where are the condenser hotwells initially filled during startup ?
CST gravity feeds to the condenser hotwells by manual operations of valves
What flowpath must be done for condensate & Feedwater systems when starting up secondary system?
Long path Recirc & over boarding flow path must be maintained until secondary chemistry is in spec
What chemicals can be added to secondary system to improve chemistry ?
Hydrazine & ammonia may be added to secondary
What flow path can be established once chemistry is in spec ?
Hotwell drawoff to the CST can be established
When can the 3rd CD Pump be started?
Can be started at >20% power
What is the normal operations for the Condensate Polishing Demins ?
Demins are supposed to be normally bypassed, but they’re usually in service due to chemistry
What loads are supplied by Condensate discharge header ?
-Condensate Service Header
-LP Turbine Hood Spray
-HTR Drain Pump Mechanical seal water
-FW Pump Seal Water
-Blowdown HEX
-Condensate cross-tie header
During plant shutdown what happens to CD Pump when reactor power is being reduced to 50% ?
-As power reduces CD Pump mini flow Recirc will increase
-Once <50% power is reached than one CD Pump can be secured
When can the second CD Pump be secured during a plant shutdown ?
Second CD Pump is secured when plant enters mode 3
During plant shutdown what is the last CD pump used for ?
-Last CD Pump will maintain long path Recirc, until main condenser is secured
-Last CD Pump will pump down hotwells to either CW Canal or CST
-After all this then pump can be secured
What will happen in order, on loss of main condenser vacuum ?
-MT will trip
-MFWP will trip
-Reactor will trip on low SG LEVEL
-AFAS will actuate restoring SG LVL
-Steam bypass control system will relieve to atmosphere
What happens if there is a sufficient size condenser tube leak ?
-Will require isolating the condenser half where leak is at
-Since one half of a condenser shell is isolated, this will require reducing power to 40%
-Hotwell will pump to circ water canal & drained oily waste sump
What will happen on a loss of a Condensate Pump ?
This will trip ‘B’ MFWP, which will cause reactor power back to 40-60%
What happens on a loss of Two Condensate pumps ?
-Will cause ‘A’ & ‘B’ MFWP to trip on low suction pressure
-Reactor will trip on low SG LVL.
Why would LP nitrogen be injected into ‘B’ MFWP Turbine exhaust ?
Will be admitted into main condenser to help purge non-condensable gases
How does gland sealing steam interface with Condensate system ?
-Unloading valve dump into main condenser
-Steam packing exhaust drain tank vacuum dragged into condenser
What happens on loss of NK to condensate system?
-Hotwell makeup valves will fail close
-Hotwell drawoff valve will fail close
-Condensate Service Header PCV wil fail closed
-Condensate mini-flow Recirc valve fails open
What will happen if you lose Air Removal system ?
-Could cause power reduction or tripping reactor
-Causes oxygen concentration to rise which will require more hydrazine
