Hello: First of all I would like to say that I am new to this forum and I might be doing something wrong (like posting something in the wrong place) and that constructive criticism is welcome. Also, I am spanish, so my english isn't the best. I have accumulated a lot of theoretical knowledge over the years, even thought I am currently trying to get the Electronic Engineering degree, I always have had interest on tinkering and experimenting with Nuclear Engineering beyond reading a lot of books and different models. So I thought, why not fuse my background of theoretical and electronics knowlege to build something? The RTG inmediately came to mind. I understand the working principle of a thermocouple and the Seebeck effect, and I am currently trying to understand the working principle of a Betavoltaic cell and how to build one. Help on that would be appreciated. I also have started thinking about the nuclear fuel that i would have to collect and use. Because I live at Spanish something like United Nuclear isn't available, and also because my funds are limited, I turned my back to Po-210 and how to obtain it from antistatic brushes and air filters. I would also like to know about what you think about that. Only thing I request is tips or protocoles to not finish like Litvinenko. My model so far consists of the nuclear fuel surrounded by graphite and filling the walls with Thermocouples and Betavoltaic cells. What do you think of this model? Suggestion and help is appreciated!