To be considered 'enriched', the uranium-235 fraction should be between 3% and 5%. This process produces huge quantities of uranium that is depleted of uranium-235 and with a correspondingly increased fraction of uranium-238, called depleted uranium or 'DU'. To be considered 'depleted', the uranium-235 isotope concentration should be no more than 0.3%. The price of uranium has risen since 2001, so enrichment tailings containing more than 0.35% uranium-235 are being considered for re-enrichment, driving the price of depleted uranium hexafluoride above $130 per kilogram in July 2007 from $5 in 2001. COUNT 5
QSN1 Between what percent fraction range of uranium-235 is uranium regarded as enriched? ANS1 3% and 5% QSN2 In what year did the cost of uranium notably begin to increase? ANS2 2001 QSN3 What is the maximum uranium-235 isotope concentration for uranium to be considered depleted? ANS3 0.3% QSN4 What was the price of a kilogram of depleted uranium hexafluoride in 2001? ANS4 $5 QSN5 How much did a kilogram of depleted uranium hexafluoride cost as of July 2007? ANS5 $130