In FPL's nuclear reactors, reactor coolant water heated by the fission process is prevented from boiling because it is kept under pressure. The nuclear reactor's pressurizer controls the primary system's pressure. The pressurizer is an elongated cylindrical tank elevated above other components of the primary system. The pressurizer is constructed of carbon steel.
Internal surfaces are clad with a high-strength stainless steel alloy.
A 10 to 12 inch surge line connects the pressurizer to the reactor coolant system. The graphic below shows a pressurizer and its parts. The pressurizer regulates system pressure during variations in reactor coolant temperature and volume due to normal or unexpected changes in power output. The table below describes how the pressurizer regulates primary system pressure. Function Process Increase water temperature and pressure 1.