The NB-36H was never powered by the reactor it carried. The aircraft used the normal (as far as that will apply to a B-36) powerplants as installed, while the nuclear reactor was powerer up in flight to assess handling, measure the effects etc.
GE once designed a nuclear powered jet engine, which was a huge double engine (two compressors, turbines) with one reactor instead of the combustion process in a normal jet engine cycle. They built the prototype up to a point but never finished or ran the beast.