just stumbled across an article on spiegel online about a new hypothesis that at the earth’s core is a giant nuclear reactor — the article mentions that there are known natural nuclear reactors in gabun. googling for “natural nuclear reactors” returns a page by the curtin university of technology. fascinating reading.
of course the hypothesis mentioned in the spiegel online article is so far just a hypothesis, but it would be a bit ironic if the “green” geothermal water heating technology turned out to be down to nuclear energy in the first place 
