Chemical and Volume Control System (CVCS) in Nuclear Reactors

Chemical and Volume Control System (CVCS)

• The CVCS provides chemical and volume control of the reactor coolant system (RCS) to ensure safe and efficient operation.

Functions of CVCS

• Reactor coolant purification, including removal of fission products, activation products, and impurities.
• Chemistry control to minimize corrosion of the RCS.
• Reactor coolant inventory regulation through addition of reactor makeup water.
• Reactivity control by adjustment of boron concentration.
• Seal water injection.
• Emergency core cooling (High Head Safety Injection).

Importance of CVCS

• Removes radioactive products and impurities through demineralizers to keep the RCS within acceptable limits.
• Reduces corrosion through chemical control.
• Supplies reactor makeup water needed due to minor leaks, evaporation, and RCP seal injection.
• Adjusts boron concentration of the RCS during all phases of plant operation.
• Provides an emergency boration path.

Interconnected Systems

• The Zinc Addition System (ZAS) adds soluble zinc to the RCS to reduce stress corrosion cracking and displace Cobalt-60.
• The ZAS interconnects with the CVCS system.

Emergency Response

• During a loss of coolant accident (LOCA), the CVCS provides an immediate source of high-pressure water to keep the reactor core cooled.