The MIT Research Reactor produces heat in addition to neutrons. In a power reactor, heat would be converted through steam into electricity. In the MIT Reactor, the 6000 kilowatts of heat is produced at a temperature so low (50 degrees Celsius – about the temperature of warm bath water) as to be useless for the production of power. The heat is carried away via heat exchangers and a secondary water system to cooling towers.
The water that flows through the core, in addition to being a moderator essential to the operation of the reactor, also serves as a coolant (see The Fission Process for more). It circulates in a closed ‘primary’ loop from the core to the heat exchangers and back to the core. The heat produced in the core is transferred to the water which is called the ‘primary coolant.’ In the heat exchangers, water in a ‘secondary’ loop picks up the heat and carries it to the cooling towers outside the reactor building and dissipates the heat into the ambient air. Because the secondary water does not come in contact with the primary water or with the reactor core, it carries no radioactivity.
The MIT Reactor has over twenty area and effluent radiation monitors operating continuously to provide an indication of radiation levels at various points both inside and outside the reactor. Several of these monitors take automatic actions, such as automatically sealing off the containment building ventilation, should they detect abnormal radiation levels.