Yep this is ridiculous.
Nuclear powered aircraft certainly existed at one point as a military experiment. The goal of it being an aircraft that can just keep flying without the need to refuel. However we haven't seen or heard anything about them ever since because they came to a conclusion that they are very impractical. In the end the whole thing became more of a dick measuring content between the US and Russia (much like the space race). Tho according to the available info the US plane never actually flew solely on nuclear power, they just flown a running reactor on a regular plane while did actual engine testing on ground. The Russians supposedly did have a plane flying on pure nuclear power, but the crew got irradiated because they left off some of the lead reactor shielding so that the plane was light enough (even tho the planes ware already rather big). They also used heat directly from the reactor, no electricity (that conversion is very inefficient and adds even more weight)
This is a basic problem with making mobile nuclear reactors (They do work on ships and submarines tho, since those can be as heavy as they want). They need a LOT of heavy shielding and we can't just use technology to work around the problem, you have to have lots of physical 'stuff' in the way to stop those energetic particles. So the huge weight of a reactor poses obvious problems when trying to build a plane that is light enough to actually fly. However planes also have a very critical weight distribution requirement, they want to have the mass close to there center to be stable while also being somewhat distributed to reduce the load on the airframe. So you can't stick the reactor far away from the planes hull, so radiation shielding becomes that much more important. Especially since they plan on flying for years at a time.
These radiation problems are stacked on top of the radiation that is caused by cosmic rays beating down on the upper layers of the atmosphere. This radiation is not that much of a problem on a few hour flight here and there in a regular plane, but if you spend years up there it does add up.