Condensate and Feedwater Flashcards
What is the purpose of the Condensate and Feedwater System?
Supply RPV with demin water at a rate equivalent to the steam generation rate (11.7Mlbm/hr at 1100PSIA)
What is the general normal main flow path from suction to FW Heaters for the Condensate System?
Hotwell -> Cond. Pps -> 40% Cond Pre-filter (bypassed) -> SJAE Condenser -> Gland Seal Condenser -> Off Gas Condenser -> 100% Cond. Filter -> Demins -> Cond. Booster -> LP Heaters
What provides make-up water to COndensate SYstem?
2/3A & B CSTs - Vacuum dragged via make-up control valve
What provides NPSH for the Condensate Pumps?
Hotwell
What is the efficiency for each section of the Hotwell?
100% cold to 97% Warm
How many SJAE condensers does the Condensate system serve?
2 normally, has a 50% bypass line.
Does the condensate normally service the tube or shell side of the SJAE Condenser?
Tube side
How many Gland seal steam condensers are normally in service and serviced by Condensate?
1 of 2.
How many Offgas condensers are normally in service and serviced by Condensate?
1 of 2
How many 100% Condensate Filters are there and what is their purpose?
4 to remove iron from water - reduces zinc injection cost
How many condensate demineralizers are there and how many MUST be in service?
7; 2 must be in operation
Where is excess Condensate flow routed?
CST downstream of demineralizers. THis is refered to as HOTWELL REJECT
What does the rejected water from Condensate/Hotwell also serve?
~100 gpm minimum normal flow is normally routed to the suction of the CRD pumps
What provides motive force to the Condensate and Cond. Booster Pumps?
A common Motor and shaft
What is the purpose of the Cond. Booster min flow valve?
It taps off the discharge of the booster pump (downstream) to provide recirc to main condenser.
- regulates recirc based on C/CB Pp amps to prevent flow instability
- Also aids in maintaining addequate flow for RFP Suction Pressure
Where does the Condensate System Enter the Feedwater System?
LP FWH strings
Where does Hydrogen Addition inject and why?
Cond. Booster Suction - to minimize IGSCC
How many strings of FWHs are there?
3
How is the bypass line for the LP Heater tube side sized? and when is it automatically put in service?
Sized to carry 33% of the flow (1 full string); “A” Heater level high
What is the purpose of Zinc Injection and what RFPs does it inject to?
Reduce dose in DW; U2 A&B; U3 B&C
Where do RFPs take suction from?
LP FWHs DIscharge
Where do the RFP Min Flow lines route to?
Condenser
How many Feed Reg Valves are there and how many are normally in service?
3; 2. At NOC, Low Flow Reg is not
What is the capacity of the Low Flow Reg Valve?
U2 11%; U3 23%
Where do the RFPs discharge to?
HP FWHs
How many FW Lines return to RPV and where to they split?
2 - in the HP Heater Bay
What other systems tap into FW Prior to RPV Injection and where do they tap in?
RWCU & HPCI; B FW Line in the X-Area
How does the FW system inject to the Vessel?
4 70degree spargers
What is the purpose of the Main Condesnser?
Condenser steam from turbine exhaust,
deaerate condensate to remove fission gases
Provide NPSH to the condensate pumps
What is the purpose of the Condenser seal trough and drain valves?
Keeps the cold end full
What is the position of the seal trough drain and fill valves for the cold and warm sections of the condenser?
Cold compartments fill valves open and drail valves closed to keep seal trough filled
Warm compartments fill valve closed and drain valve open to keep seal troughs empty
What is Standby Coolant Supply?
During emergency conditions, emergency Rx Water makeup supply from Service Water system
What are the power supplies for the C/CB motors?
Bus 23 and 24
What is the rated flow for each C/CB pump pair?
28% rated flow (3.3E6lbm/hr)
What are the Current setpoints for the C/CB pump motors?
160 to 255 amps
Where does H2 addition inject?
Condensate Booster Suction
What cools the C/CB pump seals?
Condensate/FW
Where are the Gland Seal Condensers and where do they drain to??
“A” is in “A” SJAE Room, “B” is in “B” SJAE room;
Main condenser via loop seal
What is the purpose of the Offgas condenser?
Cools superheated discharge of catalytic recombiner
How many 100% Pre-filters can be out at any given time at full power?
1
Where is backwash for 100%cond. prefilters sent?
Floor Drain Collector Tank
What are the Condensate Filter Bypass MOV Interlocks?
Partially open if 2 vessels isolated
Full open if >= 3 vessels isolated
Auto opens on low booster Pp suction pressure when in Auto
How many Cond. Demins are required for full power operation?
7
At what levels is the Condensate Demin DP maintained and how is it maintained?
between 26 and 55PSID;
Maintained by removing units from service or opening/closing Condensate Min Flow Valve
What is the minimum number of Cond. Demins that must be in service?
2
What is the danger of Cond. Demin DP becoming to low or too high, and how is it controlled?
Low - channeling develops - flow should be increased to raise DP by increasing CB Min Flow
High - fracturing of resin beads - Sequentially cut in Demin’s to counteract rising DP due to rising Cond. Flow
What are teh temp limits for the cond. demins and why?
High temps can breakdown the resin beads.
Operations with T<135F is unlimited;
135
What are the condenser/condensate pressure and temp limits?
24inHg Vacuum and 136F
What is the LP Heater Bypass designed for?
to support 33% of Full flow and restricting orifice installed to simulate DP across heater string
How many RFPs are required for full power?
all three, each rated for 43.6% flow
What is the rated flow for RFPs?
5.1E6lbm/hr, max current 1115amps
What powers the RFPs?
A- Bus 21
B- Bus 22
C- Bus 21 or 22
What powers the RFP Vent Fans?
“A” off Bus 25; “B” off Bus 26
What is the setpoint for the RFP Min flow recirc valve?
When in Auto, RFP flow <10% it opens, then closes again at 10%
Where are the RFP vibration sensor resets?
Hall to interlock
What cools the RFP Mechanical Seals?
TBCCW
What are the setpoints for the RFP Aux Oil Pump?
Auto start when pump not running OR if bearing oil pressure less than 20PSIG
Auto stop when oil pressure ~30psig
RFP trips if pressure less than 18psig
What cools the RFP oil cooler and what is the setpoint temperature?
TBCCW - 115F
What position does the Aux Oil Pump control switch need to be in to auto start?
On RFP Auto Start - NAT or NAC
On RFP Stop - NAC
What position do the FRVs fail?
Fail as is
What powers the RFP FRVs?
ESS with Instrument Bus Backup
Where are teh Condensate Makeup Pumps?
TB Main Hall 517 near RB interlock
Where do the Condensate Makeup Pumps take suction and where are connections?
Tap of CSTs at 90,000gal level - ensures 90,000gal available for HPCI
What is the function of the Condensate Makeup Pumps?
When hotewell level decreases, normal makeup valves open first,
emergency valve makeup valve opens if level continues to drop
What autostarts the condensate makeup pump?
If emergency makeup valve goes full open
What is normal Hotwell Level?
33in
What are the C/CB Trips?
Undervoltage or Overcurrent on Breaker;
“D” Pp only - Trips on LOCA signal (Core Spray) if all 4 C/CB Pps running- prevents overload on TR-22
This logic seals in and can be broken by taking c/s to PTL; however will be tripped again if 3 pumps still running and LOCA still in. PTL not needed if LOCA signal clears
What are the RFP Trips?
Less than 18psig Oil Pressure (2 out of 2 switches made up)
3 sec of 120# suct. pressure (last pump started trips)
If pressure not recovered 15 sec after 1st trip, second RFP will trip
All three trip at 100psig
RPV Level (+52 U2; +48 U3) to protect against cold water accident and Carryover to Main Turbine
Hi Level Knife Switches disable RPV Water Level Trip (902-6 back panel)
Undervoltage or Overcurrent on Breaker
What are limitations to C/CB Pump Starting?
2 starts from ambient motor temps
if motor started and runs for less tahn 30 min, then trips, 90 minutes before attempt restart
if motor has been running for longer than 30 min, one restart allowed immediately
What are the limitations for RFP start?
2 starts per hour from ambient temp
If operating for 60 minutes or idle for 180min
Lube Oil Pressure >20psig & vent fan running
When will the Standby Condensate Pump autostart?
If selected for standby AND RFP suction pressure less than 160psig or Running Cond. Pp trips
What does the selection of an RFP to standby do?
Auto opens discharge MOV
What will prevent RFP from auto starting?
Low suction pressure condition;
Under NOC, RFP auto start is >140psig suction pressure. If feed pump suction drops below 140psig, autostart becomes 160psig until pressure goes above 160psig at which point it will return to 140psig
What is Rx High Level and what does do to the RFPs?
~+50in; RFPs will trip, and standby will autostart then trip again.
Protects Main Steam Lines from water intrusion
NORMAL RFP Auto Start Requirements?
A supply breaker trips on running RFP; AND Standby RFP selected; AND Suction Pressure >140psig; AND Atleast one vent fan running; AND Oil pressure greater than 20psig
RFP Vent Fan Autostart Interlocks?
When running fan trips, standby fan autostarts
RFP will not trip on loss of vent fan (will overheat eventually)
Vent fan has to be running to start RFP
What is the EPU Runback?
Enabled at 9.8Mlbm/hr Steam Flow;
Recirc runback to 70% flow if:
<4C/CB Pps running and FW >10.3Mlbm/hr
Rx Level <25” and <3 RFPs running
What is the effect on Cond/FW on loss of IA?
FRVs fail as is if air pressure drops to 65-70psig;
RFP Min flow valve fails open
CB Min Flow valve fails as is
Loss of ESS on Cond/FW?
RFP Min Flow Valves auto swap to IB;
Loss of position indication of RFP Min Flow valves
Loss of IB on Cond/FW?
Loss of indication for Reheat Seal Trough Valves;
Full/Empty RHST lost
CB Min flow valve controller fails valve closed
RFP Min Flow valve fails open (if ESS Bus not available)
Loss of 125VDC control power 2A-2 (2B-2) on Cond/FW?
All RFPs powered from bus 21(22) lose trip capability and if standby pump pump powered from that bus, will not autostart
RFP low oil pressure trip INOP
Loss of TBCCW Impact to Cond/FW?
RFP Oil cooler loses cooling;
RFP seal coolers lose cooling water and eventually fail
C/CB pumps bearing oil coolers lose cooling water.
