This undated rendering said to come from inside Iran’s Parchin military site and obtained by The Associated Press from an official of a country tracking Iran’s nuclear activities, shows a chamber of the type needed for nuclear arms-related tests that U.N. inspectors suspect Tehran has conducted at the site. The official demanded that he and his country remain anonymous in exchange for sharing secret intelligence information. Any evidence that such a structure exists is significant in International Atomic Energy Agency attempts to investigate the alleged experiments.