Windscale, Cumbria, northwest England. A serious nuclear accident at a plutonium-mining plant for weapons purposes occurs. In one of the reactors, graphite ignites and burns for three days, releasing radioactive substances into the air. The accident is the most serious ever to occur at the time. However, it is three or four orders of magnitude less severe than Chernobyl (1986) and Fukushima (2011) in terms of release of radioactive isotopes of iodine, xenon, caesium, strontium, and plutonium.
