Jáchymov 227 zentners [11.35 tonnes] were produced), nickel, bismuth and uranium ore were also extracted. There were also other industries: an enormous tobacco factory employed 1,000 women. In addition, there was the manufacture of gloves and corks and of bobbin lace. On 31 March 1873 the town almost entirely burnt down. At the end of the 19th century, Marie Curie discovered, in tons of pitchblende ore containing uraninite from Joachimsthal, the element radium, for which she won the Nobel Prize in Chemistry. Until the First World War this was the foremost source of radium in the world. The first radon spa
Enriched uranium of reactors". Naturally-occurring uranium is made of a mixture of U-235 and U-238. The U-235 is fissile meaning it is easily split with neutrons while the remainder is U-238, but in nature, more than 99% of the extracted ore is U-238. Most nuclear reactors require enriched uranium, which is uranium with higher concentrations of U-235 ranging between 3.5% and 4.5%. There are two commercial enrichment processes: gaseous diffusion and gas centrifugation. Both enrichment processes involve the use of uranium hexafluoride and produce enriched uranium oxide. "Reprocessed uranium" (RepU) is a product of nuclear fuel cycles involving nuclear reprocessing of spent