The Nuclear Wall Chart

The World's First Human-Made Nuclear Reactor In the 1970s, Scientists Discovered a 2 Billion-Year-Old Nuclear Reactor in West Africa  — The Physics arXiv Blog In June 1972, nuclear scientists at the Pierrelatte uranium enrichment plant in south-east France noticed a strange deficit in the amount of uranium-235 they were processing. That’s a serious problem in a uranium enrichment plant where every gram of fissionable material has to be carefully accounted for. The problem lay in the ratio of uranium isotopes in their samples. Natural uranium contains three isotopes, always in the same ratios: uranium-238 (99.2744 per cent), uranium-235 (0.7202 per cent) and uranium-234 (0.0054 per cent). The problem was with the uranium-235 of which there was only 0.600 per cent. Physicists soon traced the anomaly to the supply of uranium ore from Gabon in West Africa, which contained far less uranium-235 than the ore from anywhere else on the planet, a problem that caused some consternation among nuclear scientists. So France’s top nuclear scientists began an investigation and. in the process, made one of the more remarkable discoveries in recent history.