Auxiliary Building

Auxiliary Building (PWR) or Reactor Building (BWR)

The PWR Auxiliary Building (graphic) or BWR Reactor Building is an enclosed reinforced concrete building that houses:

support systems and components that may contain radioactive liquid and gas - Chemical and Volume Control (CVCS)
high and low pressure emergency core cooling systems - Emergency Core Cooling (Safety Injection and RHR); Containment Spray
emergency ventilation and filter systems

The PWR steel containment is connected to the Auxiliary Building. The Reactor Building surrounds the steel drywell in the case of the BWR design.

Systems and major components usually located in the Auxiliary Building (PWR) or Reactor Buuilding (BWR) are listed below:

Component Name	PWR	BWR
Normal Water Makeup and Chemical Purification of Reactor Coolant System	Chemical & Volume Control (CVCS)	Reactor Water Cleanup (RWCU)
Pumps	Charging Pumps (Centrifugal or Positive Displacement)	RWCU Pump
Ion Exchangers	Cation Exchanger, Deborating Ion Exchanger, Mixed Bed Demineralizer	RWCU Ion Exchanger
Heat Exchangers (HX)	Letdown, Seal Water HX	RWCU Nongenerative HX
Filters	Letdown, Seal Water Injection, Reactor Coolant	RWCU, Seal Water Injection
Tank	Volume Control Tank
Emergency Core Cooling - High Pressure	High Pressure Safety Injection (HPSI)	High Pressure Core Spray (HPCS)
Pumps	HPSI Pumps	HPCS Pump
Supply Tank	Refueling Water Storage Tank	Condensate Storage Tank or Suppression Pool
Emergency Core Cooling - Low Pressure	Residual Heat Removal (RHR) or Low Pressure Safety Injection (LPSI)	Residual Heat Removal (RHR) or Low Pressure Safety Injection (LPSI) or Low Pressure Core Spray (LPCS)
Pumps	RHR or LPSI Pumps	RHR or LPSI or LPCS Pumps
Supply Tank	Refueling Water Storage Tank	Condensate Storage Tank or Suppression Pool
Heat Exchangers	RHR HX	RHR HX
Emergency Core Cooling - Neutron Poison	Boric Acid (BA) Storage and Makeup	Standby Liquid Control (SLC)
Pumps	BAST Pumps	SLC Pumps
Supply Tank	BA Storage Tank	SLC Tank
Containment Spray	Containment Spray	Drywell Spray / Suppression Pool Spray
Pumps	CS Pumps	DW Spray Pumps
Supply Tank	Refueling Water Storage Tank and Caustic Standpipe	Condensate Storage Tank or Suppression Pool
Emergency Cooling	Component Cooling	Reactor Building Closed Cooling
Heat Exchangers
Pumps
Tanks
Other Systems
Main Steam	Main Steam Isolation Valves, Safety Valves, Steam Dump	Main Steam Isolation Valves and Safety Valves
Ventilation	Control Room	Control Room
	Auxiliary Building Normal	Reactor Building Normal
	Auxiliary Building Special and Shield Building	Standby Gas Treatment
Electrical Load Centers	4160, 480 Volt AC	4160, 480 Volt AC
	125 Volt DC	125 Volt DC
Chiller & Chiller Surge Tank Pumps
Penetration Room
Hot Machine Shop
Sampling System Area
Main feedwater Pipes
Remote Shutdown Panel Room
Personnel Hatch (Access to Reactor Containment Building)