Though it is not easy.. It is "Easier" than most think. There are a number of colleges that run their own very small scale "research" reactors. One of them was used to create the "fuel" for the US rover (Curiosity) on Mars and the rover needed international "clearance" since it uses a radioactive source as its power source.
Source: https://mars.nasa.gov/msl/spacecraft/rover/power/ Archive: https://archive.today/PdqlD
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