CD- Condensate Flashcards
What is the purpose of the Main condenser?
Condenses and collects turbine exhaust steam and various equipment drains
Collects and stores condensate in the hotwell, acting as a reservoir for use in the S/G
What connects the Condenser shell to the LP turbine?
Main Condenser Expansion Joint (Dog Bone seal)
What is the purpose of the Dogbone seal?
Prevents air leakage into the condenser while allowing movement between the turbine casings and condenser sections
The dogbone seals have a trough around the seal that is normally dry. When would it be filled and what fills it?
Filled with Condensate Service Header during a Degraded Vacuum event
What is the purpose of the water sealed Condenser Equalization Duct and where is it located?
Located above A and B shell false bottoms
Allows pressure between the sections to equalize if an abnormal pressure/temperature differential develops
(the water seal will “blow out”, thus equalizing pressure, if the temperature in any section exceeds that in the adjoining section by 30F)
How is each section of the condenser protected from overpressure?
Rupture discs set at 5 psig on its associated LP turbine hood
Why have the main condenser tubes had plastic lath installed? How many tube bundles are in each section of the condenser sections?
To prevent vibration failure of the tubes
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Why do the tube lengths vary in the three condensers?
To compensate in part for the progressively higher CW temperatures since it flows through them in series
(higher temps means higher pressure per condenser section)
What is the purpose of the Condenser Waterboxes?
Provide the supply and return headers to the condenser tubes
provide air removal piping
Where are the air off-take pipes installed and how far do they extend?
At the center of each tube bundle to remove air and non-condensable gases
Extend the tube bundle length
How can the condenser Reheater Tray (inner bottom) level affect ‘A’ AFP operability after a LOOP?
After an MSIS, reheater tray level can rise and potentially back up the steam line drains and cause the pump to be inoperable.
Why are the hotwells equipped with spargers? When would they be used? Is this a normally performed evolution?
Could be used to admit AS directly into the condensate located in the hotwells
Can be done during startup to heat the water for cleanup purposes
This operation is not normally performed
Where are the Longitudinal divider plates installed? Purpose of the plates?
These plates ensure condensate formed around a given set of tube bundles will flow to the associated hotwell half
This feature allows continued operation if a tube leak occurs in one CW flowpath
The corresponding hotwell half can be isolated and pumped out to the Circ Water System by one of the condensate pumps to minimize further secondary system chemical contamination
What is the purpose of the Condensate detention time in the CD system? What is the total distance traveled by the condensate from the inner bottom sump to the hotwell outlet to the CD pumps?
Aids condensate reheating and sampling
a full condenser shell length
Why is there a salinity detection bay provided near each main condenser waterbox?
To detect CW leakage between the tubes and tube sheet
How much condensate storage volume is provided by the condenser hotwell?
100,000 gallons
What is the condensate storage volume of the condenser hotwell based on?
4 minutes of operation at “valves wide open”
What CST level would cause the two Hotwell Makeup valves to auto shut?
30’
How do the condenser Hotwell Automatic Makeup valves respond to a loss of IA?
Fail closed
Where are the condenser Hotwell Automatic Makeup valves located?
140’ Turbine Building, North side of shell ‘A’.
Where are the condenser hotwell manual make up valves located?
100’ Turbine Building, North side of shell ‘A’
The single draw-off automatic control valve will open based on the higher of two levels of what condenser hotwells?
1C or 2C
How does the main condenser hotwell draw-off auto control valve react to a loss of IA?
Fails closed
What are the interlocks associated with the main condenser hotwell draw-off control valve?
It will automatically close when either SG feedwater pump suction pressure is low or any condenser hotwell cation conductivity is high
If the main condenser hotwell draw-off control valve closes due to high conductivity, how can I operate it?
By placing the key-locked bypass switch to the bypass position at the local panel
(no main control room control)
Concerning bypassing the main condenser hotwell draw-off control valve, what else can I use the key-locked bypass switch position for?
To drain the hotwells to the CST
How are the CD pump suction and recirculation valves interlocked? How many suction and recirculation valves does each CD pump have?
When the suction valve goes closed, the corresponding recirculation valve goes closed
A and C both have 1
B has 2
When will the CD pump suction strainer D/P switch alarm in the control room?
5” H2O
When are the CD pump strainers required to be cleaned?
D/P of 7” H2O
Where does the seal water for the CD pumps come from?
Condensate Service Header
Concerning the CD pump, how are the upper and lower bearings lubricated? How many stages are these pumps?
Upper – oil lubricated, with oil cooling water supplied by TC system
Lower – grease lubricated
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What is the purpose of the CD pump minimum flow lines? What system is used to fill this line prior to starting the first pump?
Maintains the minimum allowable flow through the pump when the normal discharge flow path is isolated or partially isolated. Keeps the CD pumps from overheating.
DW
What is the CD pump mini-flow normally set to by the operator? Where do they discharge to?
4500 gpm
respective hotwell half in the C condenser section
What is the low recirc flow trip setpoint on the CD pump mini-flow line?
3600 gpm after 45 seconds
How do the CD pump mini-flow valves respond to a loss of IA or power?
Fail open
What happens to the CD pump mini-flow valves when its associated pump stops or is tripped?
Valve goes closed (Solenoid is energized)
The “B” CD pump has two suction valves and can be aligned to take suction on both (normal lineup) or either side (abnormal lineup). How could the position of ‘B’ CD pump’s two suction valves affect the pump?
At least one of the two suction valves from 1C or 2C must be full open or the ‘B’ pump will trip
What is the normal operating level of the condenser hotwell?
41 inches
At what level in a condenser hotwell half will the associated CD pump trip? How many level switches are there for each hotwell half?
30 inches
2 level switches per half
(B pump has two sets, one for each hotwell half)
What are the power supplies for all three CD pumps?
‘A’ & ‘B’ – NBN-S01
‘C’ – NBN-S02
Which CD pumps have connections to the ‘Overboard Valves’? Where do these overboard lines lead to?
‘A’ & ‘C’
CW canal
What is the purpose of the ‘Overboard’ lines in the CD system?
Allow for a ‘feed and bleed’ of the condensate and feed systems to remove system impurities, specifically rust, following dry layup conditions during refueling outages
What must be done prior to using the ‘Overboard’ lines in the CD system?
Condensate verified to be non-radioactive through chemistry sample
To what pressure is the Condensate reduced when going into the Condensate Service Header?
90 psig
If no CD pumps are available, what can be used to supply the Condensate Service Header?
DW
What are the major loads provided by the Condensate Service Header?
CD pump seals
Condenser Expansion Joints
Vacuum Pump Makeup
Hydrazine & Ammonia Dilution
Cooling jacket around the Heater drain pump mech seal
How are the Demin Inlet and Outlet valves interlocked in the CD system?
When the inlet valve is opened it provides an open permissive for the outlet valve
What is the interlock associated with the Demin bypass valve in the CD system?
When both the inlet and the outlet valves are open, a modulate permissive for the bypass valve is generated
The bypass will modulate to maintain set pressure if both the inlet and outlet valves are open and demin D/P is less than ~55 psid
> 55 psid, the bypass will be full open
At what temperature is the condensate when it enters and exits the LPFW heaters?
130F entering
330F exiting
How do the LPFW heaters respond to a high level? What is the CD flow path through a LP FW heater?
High level control valves will attempt to divert excess water into the condenser
enters through the lower tube bundles and exits through the upper tube bundles
How do the LPFW heaters respond to a high-high level?
Condensate flow will be automatically isolated to that heater string by two motor operated valves
What happens upon a loss of condensate that results in both feed pumps tripping offline?
Reactor will trip on low S/G water levels followed by a MT and Main Generator Trip
Aux Feed system will start and restore S/g water levels
What happens upon a loss of condensate that results in only one feed pump trip?
Reactor power cutback will initiate which will reduce turbine and reactor power to between 25 and 75% power
What will happen if there is a loss of main condenser vacuum?
Will prevent the SBCS valves from dumping to the condenser
The main turbine will trip followed by a trip of both Main Feedwater Pumps
Reactor will trip on low S/g water level and Aux Feedwater system will start and restore S/G level
How is CD affected by a loss electrical power?
CD pump mini-flow valves will fail open, which prevents running the pump with the discharge valve closed and no mini-flow
Hotwell make-up and drawoff valves fail closed, so hotwell level control will need to be performed manually
How is CD affect by a loss of IA?
Condensate service header control valve will fail closed, so header will have to be supplied by DW
Condensate Cross-tie pressure control valve will fail closed
Vacuum breakers isolation valves fail closed
Demin bypass valve fails open, which may impact secondary chemistry
CD pump mini-flow valves fail open
Hotwell make-up and draw-off valves fail closed
Which end of the condenser shells is the air pulled to by the AR system?
CW inlet side
How does the ED (extraction steam and drains) system interface with the Condensate system?
1 LPFW heaters and high level dump valves from various heaters route to the main condenser
Where do the Main FW pump turbines exhaust their steam to?
main condenser
Where is the main Feedwater pump mini-flow and seal leak-off routed to?
main condenser
What dumps into the main condenser from the Gland Steam system? When?
unloading valve and packing exhauster drain tank
when there is an established vacuum
What is the purpose of the condensate cross-tie header?
allows a unit that’s supplying another unit with steam to receive the returning condensate
in emergency situations, to pump condensate from one unit to another
Where are the main condenser hotwells located?
100’ turbine building
condenser extends up to the 140’
Where in the main condenser are the reheat trays? What is the source of steam flowing through them? Where is the uncondensed reheat tray steam condensed?
below the perforated plate that is the bottom of the A and B condenser shells and above the hotwell water level
steam from the main feedwater pump turbine exhaust
C condenser tubes
What is the capacity of the CD pumps?
50% each
9100 gpm each
Which condenser hotwells do the CD pumps take suction on?
A- 2A, 2B, 2C
B- can take suction on both or either loop
C-1A, 1B, 1C
What is the main purpose of the Condensate pumps?
take a suction on the condenser hotwells and provide that water as suction head for the main feedwater pumps
What is installed just upstream of each Condensate pump suction? What is the control room alarm setpoint for high D/P? When must the strainers be cleaned?
inline strainer
5” water level
7” water level
What does the CD system do for S/G blowdown?
cools the Blowdown HX
