Good news: Cameco is benefiting from a boom in nuclear fuel demand. Bad news: Its price has already gone up a lot. Shares of Canadian nuclear fuel producer Cameco (CCJ 6.48%) were up 6.1% through 11:45 a.m. ET on Friday, helped by a decision by the U.S. government. As Bloomberg reported yesterday, the government wants to buy $3.4 billion worth of nuclear reactor fuel and is soliciting bids from uranium miners. Cameco, the biggest publicly-traded pure play on uranium production, is a logical beneficiary. Why ...