(CH)- Boric Acid Concentrator Flashcards
What is the purpose of the BAC feed valve, CH-287?
A modulated fail-closed valve which maintains a flash tank Setpoint level via the flash tank level indicator controller LIC-287
The setpoint corresponds to a predetermined flash tank level and is dialed into LIC-287 at the control panel
What’s included in the BAC concentrate loop?
The concentrate pumps, concentrate heater, flash tank, interconnecting piping, valves, instrumentation and controls
Concerning the BAC Concentrate Loop, what would you expect to see operating during normal ops?
Both of the 1500 gpm concentrate pumps operate in parallel to provide the 3000 gpm process fluid circulation through the heater into the flash tank
In regards to the BAC Concentrator, what effect on its operation will occur upon a loss of either circulating pump?
Will not cause a concentrator shutdown or loss in processing capacity, but continued single pump operation will increase the tendency of the heater to foul
Two check valves are installed downstream of each pump to preclude backflow during single pump operation
Concerning the check valves downstream of the BAC Concentrate circulating pumps, why is there a 3/8” perforation?
To provide limited concentrate recirculation during single pump operation, which will keep the non-operating pump sufficiently heated to prevent precipitation of solids
Approximately how hot will the concentrate be when it enters the flash tank in the BAC system?
240F
What system provides cooling to the BAC Concentrate cooler?
Nuclear Cooling
Why do we backwash two of the three demisters in the BAC flash tank?
Assists in removing any boric acid or other impurities which are entrained in the vapor stream
How can I remove tritium from the BAC skid?
Distillate steam form the Vapor Separator may be directly discharged to plant piping through CHN-V282 and out the plant vent
What would be the adverse effect of using insignificant flow from the steam vent in the BAC system?
Will starve the distillate system and require the use of RMW to supplement distillate water for Distillate Flush functions on the skid
What is the purpose of the CVCS Holdup Tank and what is its capacity?
Stores all recoverable Reactor Coolant and provides the NPSH required for operation of the Holdup Pumps
holdup capacity for recycle waste water produced during refueling and power ops
hold up capacity for drains, reliefs and leakage collected in the RDT and EDT
550,000 gallon capacity
What temperature is maintained in the CVCS Holdup Tank and how is it maintained?
Maintained above 60F by two sets of redundant 25 kW heaters
At what level in the CVCS Holdup Tank will the BAC be used to begin processing?
17 feet
Where does the CVCS Holdup tank vent to? Where is this tank located?
Fuel Building Ventilation
RCA yard next to RMWT
What is the basis of the CVCS Holdup Tank capacity?
Designed to store all recoverable water from back-to-back cold shutdowns to 5% subcritical and subsequent startup at 90% core life
What is the purpose of the CVCS Holdup Tank Pumps?
Two pumps to transfer the contents of the CVCS Holdup tank to the BAC
recirculate the CVCS holdup tank contents
What is the purpose of the recirculation line on the CVCS Holdup Tank pumps?
Recirculation line goes back to the HUT to prevent dead heading the pump when the BAC inlet valve cycles
What is the capacity of the CVCS Holdup Tank Pumps?
50 gpm each
Where are the CVCS Holdup tank Pumps operated and how are they interlocked?
Controlled manually at the CVCS hold up tank pump room next to the HUT
Interlocked to prevent both pumps from operating simultaneously
What would stop the CVCS Holdup tank Pumps automatically?
Lo-lo CVCS holdup tank level
High BAC level
Diversion of letdown flow to the Pre-Holdup Ion Exchanger when the contents are being purified
What is the purpose of the Boric Acid Concentrator?
Processes relatively good quality equipment drain type inputs stored in the CVCS Holdup tank by heating and vaporizing the fluid
increases the boron concentration of the BAC bottoms to a level greater than the RWT, where the borated water is normally sent for reuse
If one of the Boric Acid Concentrator pumps becomes inoperable, why will the BAC be secured when the batch is completed?
Because continued operation can cause heater fouling
How are the BAC pumps protected from cavitation?
By the flash tank lo-lo alarm/cutout
What is the heat source of the Boric Acid Concentrator Heater? Where does that source go to after the heater?
Aux Steam
Steam condensate is returned to the Auxiliary Steam Condensate Receiver Tank
Where is the BAC heater located?
In the BAC room on the 120’ of the Radwaste building
What is the purpose of the BAC flash tank?
Tank is at a reduced pressure that allows the contents of the BAC to boil
water vapor is removed as steam
What takes suction off the BAC flash tank? Where is the flash tank located?
Concentrator pumps
BAC room 120’ RW building
Concerning the BAC, what outlet temperature is maintained by the Concentrate Cooler and why?
175F to prevent solidification of boron in RWT piping when the concentrate outlet valve opens
Concerning the BAC, how much of the Concentrate Cooler outlet recirculates back to the suction of the Concentrator Pumps? Where is the cooler located?
5 gpm to provide an indication of density through DT-295
BAC room
Regarding the BAC, what does the Vapor Separator consist of? What cleans them? What happens when there is a high D/P?
Three layers of mesh pads that act as demisters of entrained liquids
spray nozzles
operator opens a valve and distillate produced at the skid flushes the bottom two pads
Concerning the BAC, what is the maximum vapor release flowrate from the Separator? Where does the dry vapor go when leaving the vapor separator?
9000 lb/hr or as the effluent release permit allows
vapor condenser and plant vent
Concerning the BAC, what is the purpose of the Vapor Condenser?
Uses Nuclear Cooling water to remove thermal energy from the vapor, converting the vapor back to the distillate, which in turn controls system pressure
In regards to the Vapor condenser, what effect does more or less cooling water have on the BAC system?
More cooling water lowers system pressure, less cooling water allows system pressure to rise
Regarding the BAC vapor condenser, when is PCV-993, cooler vent, fully open? what is sent through this flow path? Where is the vapor condenser located?
At 6 psig
non condensable gases
BAC room
During shutdown conditions, what is the purpose of the Nitrogen connection in the BAC system?
Supplies nitrogen at 2-3 psig to prevent pulling an excessive vacuum during cooldown and to inhibit corrosion
What is the purpose of the BAC Distillate Pumps? When do they start?
Provide flow from the Vapor condenser to the Distillate Cooler through a conductivity cell and then to the BAC condensate ion exchangers and RMWT, flush lines for the vapor separator and seal water for the BAC pumps
when there is sufficient level in the vapor condenser
What is the purpose of the BAC Distillate cooler? Location?
Removes heat from the distillate to protect the resin in the Ion Exchanger
BAC room
What is the maximum outlet temperature of the Distillate Cooler in the BAC system? What is the hi alarm set point?
130F
150F
What is the purpose of the BAC Concentrate Transfer Pumps? Capacity? Location?
Provide flow from the heater through the Concentrate Coolers to one of the following locations: CVCS Holdup tank, LRS Concentrate Monitor Tanks, RWT
25 gpm
BAC room
What is the purpose of the Boric acid reclamation system?
when the contents of the CVCS HUT need to be processed.
processing by the BAC concentrates the boron so that we can reuse the water in the RWT
In the BAC, a portion of the vapor produced is removed as distillate release which is sent to the plant vent. Where does the rest of the vapor go?
condensed and cooled for pump seals and flash tank level instrumentation
the bulk of the remaining condensed liquid is sent back to the BAC skid
When the boron concentration of the CVCS hold up tank is sufficient, where are its contents sent to?
RWT
Normally, the BAC concentrates are sent to the CVCS holdup tank. Where else can they be sent?
LR concentrate monitor tanks for disposal
What is needed in order to release BAC steam vapor to the plant vent?
release permit from the effluents group
Where is the BAC located?
120’ RW building
What is the purpose of the BAC concentrator pumps? Capacity? location?
provide process fluid through the BAC heater into the flash tank
50% at 1500 gpm each
120’ RW building
What is the purpose of the BAC concentrator pumps discharge check valves?
prevent substantial back flow during single pump operation
3/8” hole in the check valve to allow limited backflow, preventing boric acid solidification in the pump
What is the capacity of the BAC distillate pumps? What provides flushing and seal water flow to the mechanical seals? location?
25 gpm each
distillate flow through a separate line
BAC room
What side of the BAC concentrate heater is the AS steam flow admitted to?
shell side
What is the BAC flash tank equipped with for a 60 psig relief?
rupture disk
What side of the BAC concentrate cooler is the nuclear cooling water flow admitted to?
shell side
