Reuters: President Barack Obama announced $8.3 billion in loan guarantees on Tuesday to build the first U.S. nuclear power plant in nearly three decades, a move designed to help advance climate legislation in Congress. Obama, a Democrat trying to win Republican support for a bill to overhaul U.S energy practices, said the United States needed to increase its supply of nuclear power to meet its energy needs and fight climate change. The government backing will go to help Southern Co …