Jan 6 (Reuters) - United States-based Energy Fuels Inc (UUUU.A) said on Thursday it could start producing 500,000 pounds annually of uranium within six months if prices for the nuclear fuel rise due to the political unrest in Kazakhstan. Energy Fuels says its production could then ramp to 2.5 million pounds annually within 18 months if spot prices, which hit $45.50 per pound on Wednesday, rose "moderately higher" and a customer signed a long-term contract. Energy Fuels does not produce any uranium currently due in part to low prices - fueled by Kazakhstan"s control of more than a fifth of the global market - though it has reserves in Utah, Texas and Wyoming.