The heated propellant would be fed through a conventional rocket nozzle to produce thrust.

This uses a double-hulled rocket nozzle that allows the rocket fuel to circulate as a coolant.

The second method would use injectors which sprayed a water and alcohol mixture onto the rocket nozzle, cooling it.

Expansion in the rocket nozzle then further multiplies the speed, typically between 1.5 and 2 times, giving a highly collimated hypersonic exhaust jet.

Nuclear thermal rockets pass a propellant over a central reactor, heating the propellant and causing it to expand rapidly out a rocket nozzle, pushing the craft forward.