When US diplomats in Switzerland were haggling with Iran over its nuclear program, they had a unique source of knowledge: a "secret replica" of Iran's own facilities sitting in Tennessee, reports the New York Times. It seems the US has built one inside the sprawling Oak Ridge nuclear complex, complete with centrifuges, and American scientists use it to evaluate what is and isn't possible on the Iranian side. “We know a lot more about Iranian centrifuges than we would otherwise,” one anonymous expert tells the newspaper.
The larger story describes how Oak Ridge and the nation's eight other atomic labs have been working together to provide crucial information to negotiators, often under tight deadlines. The Times describes the effort as a "Manhattan Project in reverse"—that is, scientists aren't trying to build a bomb, they're trying to prevent one from being built. As talks resume in Vienna, Reuters reports that the biggest issue revolves around sanctions. Iran wants them lifted as soon as a deal is in place—the goal is the end of June—while the US wants to phase them out. (Read more Iran nuclear weapons program stories.)