Manori Ravindran International Editor High-profile espionage cases in the post-war period often invoke the grisly fate of the Rosenbergs, the first U.S. citizens to be convicted and executed by electric chair for sharing atomic secrets with the Soviet Union in peace time. But in the new documentary “A Compassionate Spy,” filmmaker Steve James tells the incredible story of Manhattan Project scientist Ted Hall, who shared classified nuclear secrets with Russia — and got away with it. The Participant and Kartemquin Films-produced documentary, which has its world premiere in Venice on Sept. 2, is one of a number of films at this year’s festival that tackle the topic of nuclear disaster: Projects from Noah Baumbach’s feature adaptation of Don DeLillo’s “White Noise” through to Oliver Stone’s on-the-nose documentary “Nuclear” all contemplate some aspect of our nuclear past and future.