You realize, of course, that not too long ago we were launching actual nuclear bombs into the upper atmosphere and detonating them on purpose. And it didn't really mess things up that bad.
In that context, the remote possibility that a rocket might accidentally fail in a way that somehow managed to crack open its little reactor, spilling some radioactive material in a way that somehow harms anything whatsoever, would seem quite trivial. I'd be more worried about airliners crashing into me on the freeway if I were you.
In other words, I'll bet you five bucks that nothing radioactive will drop onto your house the next time they launch a satellite with a nuclear reactor onboard.
You should really check out the safety features of RTGs. As one example, in 1970 the lunar module from the failed Apollo 13 mission (which had an RTG with a plutonium dioxide core) was burnt up over Fiji and dropped into the Tonga trench in the Pacific. The heat and stress of this event was far beyond anything that would happen during the launch of a spacecraft. The area where the RTG ended up is still tested for an increase in background radiation and to date nothing has shown up that would indicate that the containment vessel has leaked.
But we are not talking about RTG:s here, we are talking about real reactors.
... Which are potentially even safer, because the fuel is not terribly radioactive until it has actually been in the reactor. Ship it up in parts, assemble when safely in orbit.
In that context, the remote possibility that a rocket might accidentally fail in a way that somehow managed to crack open its little reactor, spilling some radioactive material in a way that somehow harms anything whatsoever, would seem quite trivial. I'd be more worried about airliners crashing into me on the freeway if I were you.
In other words, I'll bet you five bucks that nothing radioactive will drop onto your house the next time they launch a satellite with a nuclear reactor onboard.