ALMR Cooling System

The ALMR uses liquid Sodium as a coolant. Sodium is the coolant of choice because of its poor neutron moderating abilities and because it has terrific heat transfer characteristics. Being a highly conductive liquid metal, most of the heat transfer occurs through conduction. Sodium does, however, absorb some neutrons and transforms into Na-24 which is radioactive. Thus, the ALMR is a pool-type reactor with a secondary Sodium loop to insure that no radioactive Sodium leaves the reactor vessel.

The coolant system is unpressurized because Sodium is liquid at atmospheric pressure. Thus, explosive loss of coolant from pressurized pipe lines does not exist. The primary coolant inlet temperature is 640 degrees Fahrenheit (338 degrees Celsius) and its outlet temperature is 905 degrees Fahrenheit (485 Celsius). It is this thermal energy gained in this temperature rise that will eventually be converted into electricity.