An executive at an electrical utility company needs to order uranium fuel from a mine. This utility operates a single 500 MWe PWR power plant operating at an overall thermal efficiency of 33.33 percent. The fuel needs to be enriched to the 5 w/o in U235. Consider that the enrichment plant generates tailings at the 0.2 w/o in U235 level. Calculate the yearly amount of natural uranium metal that the executive has to contract with the mine as feed to his nuclear unit.