BUT WHATEVER DO YOU MEAN EMON, SURELY YOU COULD NOT BE REFERRING TO OUR GOOD FRIEND FORD
A lot of people assume a nuclear reactor is like a big car engine filled with murder. They don't seem to realize that, generally speaking, they're big, heavy, solid, and made with almost no moving parts. They are, essentially, a gigantic concrete block with some metal rods sticking out of it. Gaseous core nuclear reactors use a fuel mixture with the moderator built in (I believe it's something like a boron-uranium silicate). So the reaction can't sustain itself. A shotgun-style scram system essentially peppers the reaction chamber with extra neutron-absorbing pellets. As soon as this happens the leftover reactants cool down and solidify. GCNR designs also typically call for a liquid hydrogen coolant, so even if the reactor did somehow manage to crack open (probably because another plane accidentally dropped an aircraft carrier onto it) there are no fluids to carry particulate matter out of the reactor and no moderator that stays radioactive as it enters the atmosphere. A nuclear powered plane also wouldn't
burn if it crashed, which means they'd be much safer - most people survive plane crashes and die of smoke inhalation before they can escape.
If we were flying nuclear-powered aircraft in 2001 9/11 wouldn't have happened.