Interestingly, given the right conditions, chain reactions can take place with very little effort. There is one known example of a natural nuclear reactor that

Interestingly, given the right conditions, chain reactions can take place with very little effort. There is one known example of a natural nuclear reactor that was in operation for a few hundred thousand years (2 billion years ago). https://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor https://en.wikipedia.org/wiki/Natural_nuclear_fission_reacto...