Direct cycle nuclear engines would resemble a conventional jet engine, except that there would be no combustion chambers. The air gained from the compressor section would be sent to a plenum that directs the air into the nuclear reactor core. An exchange takes place where the reactor is cooled, but it then heats up the same air and sends it to another plenum. The second plenum directs the air through a turbine (powering the compressor), then out the exhaust, providing thrust. The end result is that instead of using jet fuel, an aircraft could rely on the heat from nuclear reactions for power.
