3710 Chemical and Volume Control System

Subsystems of CVCS

• Charging

• Letdown

• Purifiction

• Boron Control

• Volume

• Reactor Coolant Makeup

• Chemical addition

• Leakage Collection

Charging Subsystem

• Adds and removes water in RCS

• Coolant Inventory and pressure Control

Boron Control Subsystem

• Controls boron concentration for reactivity control

Letdown Subsystem

• Adjusts coolant Inventory to regulte volume and allow purification

Purification Subsystem

• Removes impurities using filters

Chemical Addition Subsystem

• Adds chemicals, such as pH-control agents, to maintain proper reactor coolant chemistry and reduce corrosion.

Leakage Collection and Recovery Subsystem

• Coolant can be recovered and reused

Volume Control Tank

• provides a source of coolant for charging pumps. It can also collect gas separated from the coolant.

Reactor Coolant Makeup Subsystem

• Supplies treated water to replace coolant losses

Letdown Flow path

• Letdown Control Valve

• Heat Exchanger

• Irifaces

• Regenerative Heat Exchanger

• Filters

• Demineralizers

• Volume Control Tank

Letdown Control Valve

Regulates the amount of reactor coolant removed from the RCS

Letdown Heat Exchanger

Cools the hot letdown coolant before it enters downstream

Letdown Orifaces

Limit letdown flow and help control pressure reduction

Regenerative Heat Exchanger

Transfers heat from hot letdown coolant to incoming charging coolant

Filters and Demineralizers

Remove dissolved ionic impurities and contaminants

Volume Control tank

Receives processed letdown coolant and provides a source of coolant for the charging pumps.

Charging Flow path

• Charging Pumps

• RegenerativeHeat Exchanger

• Charging Heat Exchanger

• Check Valves

• Boron Injection Connection

Charging Pumps

Provide the pressure needed to inject coolant back into the high-pressure RCS

Charging Flow Control Valve

Regulates charging flow

Regenerative heat exchanger

Preheats charging coolant using heat recovered from letdown

Charging Heat Exchanger

Adjusts charging coolant temperature

Check Valves

Prevent reverse flow from the RCS into the charging system

Isolation Valves

sections of the charging system to be isolated for maintenance

Boron Injection Connection

borated water to be added to the charging flow

Reactor Makeup System Components

• Makeup water Storage Tank

• Makeup Water Pumps

• Boric Acid Storage tank

• Borric Acid transfer Pumps’

• Demineralizers

• Flow contro Valves

• Controls

Makeup Water Storage Tank

Stores treated water for replenishing3

Makeup Water Pumps

Transfer water from storage into the chemical and volume control system

Boric Acid System

• Storage Tank

  • Stores concentrated boric acid solution for adjusting reactor coolant

• Transfer Pumps

  • Transmit boric acid solution into the makeup flow path

Normal Makeup

• Adds treated, demineralized water to replace normal coolant losses

• Maintains RCS inventory

Boration                                         

Adds borated water to increase the boron concentration in the reactor coolant, reducing reactivity.

Dilution

Adds low-boron or unborated water to decrease the boron concentration, increasing reactivity.