Dec 272012
A layout illustration of the General Electric XNJ140E-1 nuclear turbojet. This is the developmental engine, not an operational engine, and does not seem to have a chemical afterburner.
A layout illustration of the General Electric XNJ140E-1 nuclear turbojet. This is the developmental engine, not an operational engine, and does not seem to have a chemical afterburner.
but it does have fuel injection nozzles (50 pcs) at around station 310 ..
are those there to increase thrust for take off, or are they there for start up and shut down? (i suspect the first, becasue increasing thist by injecting fuel before the turbine section possibly might melt the turbine)
starting up the engine on chemical fuel, and only once a steady state has been reached, switch over to nuclear? i suspect getting the engine “hung” during start up on the reactor might end in a molten reactor ..
being able to run the engine for a time on chemical fuel AFTER the reactor has been shut down possibly would also allow you controlled, prolonged cool down of the reactor (both thermally and radiation wise – doing this in the air for a short time before landing should reduce resuidual activity in the core quite a bit)
and finally, being able to run the engine on chemical fuel gives you some emergncy power in case you have to shut down the reactor in flight for unspecifed reasing
> increase thrust for take off,
Yes. Nuclear engines are fine for constant-power cruise, but the much higher power levels required for takeoff make chemical fuel far more attractive.