I don’t mean to be disrespectful of your years of training and work that may have left you with many large and difficult problems to get around but the thoughts on absolutism have me unable to keep my mouth shut. A reader of most of the material concerning fission will say without a doubt that anyone with the material resources can construct a fission device. All that is required is the pilling of U235 in one place and in enough quantity and fission will ensue (you cant stop it with a high school diploma). One can calculate the cross-section required and ba-dah-bing a working device. The reason that it took so many scientists to do this is that it was a race, and the stakes were high. They had to get it right the first time and every time after that (safely) I do not understate their work they had allot to do and the pioneering act alone was impressive. However the construction of a device capable of fission is not absurd in the sense that it can be done by the inexperienced. I just wouldn’t be reckless enough to attempt it myself.
Like I said I don’t disrespect you I just think your views on this matter are misled (it happens to the best of us), if a kid came up to me excited about science and said "I am going to make an X-ray machine" I would do my best to help the bright young mind along, pointing him to the right supervision and providing him all the support he needs. Otherwise he will end up doing it anyway without the proper supervision (it would probably work too), or become disinterested in the sciences because we are a bunch of crabby aristocrats, and there goes a potential Livermore, abusing himself on videogames and TV instead.
I would say, to the subject of the thread: go find a cheerful physicist, do the work on paper, come up with all the calculations and dimensions, explain why you think the device would work, elaborate on the things you discovered while on your paper project, and look at their face, if impressed you did good, if they take you under their wing you did excellent and that would be almost as satisfying as getting thrown in prison for making a working reactor! Plus you may live through it.