25
" The simplest form of nuclear reactor requires no equipment at all. If the right quantity of uranium 235 is gathered in the presence of a neutron moderator—water, for example, or graphite, which slows down the movement of the uranium neutrons so that they can strike one another—a self-sustaining chain reaction will begin, releasing molecular energy as heat. The ideal combination of circumstances required for such an event—a criticality—has even aligned spontaneously in nature: in ancient subterranean deposits of uranium found in the African nation of Gabon, where groundwater acted as a moderator. There, self-sustaining chain reactions began underground two billion years ago, producing modest quantities of heat energy—an average of around 100 kilowatts, or enough to light a thousand lightbulbs—and continued intermittently for as long as a million years, until the available water was finally boiled away by the heat of fission. "
― Adam Higginbotham , Midnight in Chernobyl: The Untold Story of the World's Greatest Nuclear Disaster
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" A year after Calder Hall opened, in October 1957, technicians at the neighboring Windscale breeder reactor faced an almost impossible deadline to produce the tritium needed to detonate a British hydrogen bomb. Hopelessly understaffed, and working with an incompletely understood technology, they operated in emergency conditions and cut corners on safety. On October 9 the two thousand tons of graphite in Windscale Pile Number One caught fire. It burned for two days, releasing radiation across the United Kingdom and Europe and contaminating local dairy farms with high levels of iodine 131. As a last resort, the plant manager ordered water poured onto the pile, not knowing whether it would douse the blaze or cause an explosion that would render large parts of Great Britain uninhabitable. A board of inquiry completed a full report soon afterward, but, on the eve of publication, the British prime minister ordered all but two or three existing copies recalled and had the metal type prepared to print it broken up. He then released his own bowdlerized version to the public, edited to place the blame for the fire on the plant operators. The British government would not fully acknowledge the scale of the accident for another thirty years. "
― Adam Higginbotham , Midnight in Chernobyl: The Untold Story of the World's Greatest Nuclear Disaster