Chemistry: A Volatile History to investigate. Marie Curie began her investigations by testing a uranium ore called pitchblende with an electrometer. She discovered it was four times more radioactive than pure uranium, and wondered if this was due to the presence of an even more radioactive element in the pitchblende. Curie began stockpiling tonnes of pitchblende, then in the most basic of workshops with primitive equipment she undertook a multitude of complex and dangerous procedures in an attempt to isolate this new element. In the event, Curie discovered two new elements, polonium named after her native Poland and radium. Whilst these were naturally occurring
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