U.S. Secretary of Energy Steven Chu reacts as he attends the 56th IAEA General Conference at the UN headquarters in Vienna September 17, 2012. REUTERS/Herwig Prammer

 
U.S. Secretary of Energy Steven Chu reacts as he attends the 56th IAEA General Conference at the UN headquarters in Vienna September 17, 2012. REUTERS/Herwig Prammer
U.S. Secretary of Energy Steven Chu reacts as he attends the 56th IAEA General Conference at the UN headquarters in Vienna September 17, 2012. REUTERS/Herwig Prammer