WASHINGTON — For six years, international nuclear inspectors have been demanding that Iran turn over evidence of experiments that they suspect could have been part of a secret effort to solve the complex science of detonating a nuclear weapon. On Friday, the International Atomic Energy Agency , the monitoring arm of the United Nations, said that it was finally beginning to see the information it had long sought — but that Iran insisted that the detonators were for non-nuclear purposes. The disclosure was buried in a report by the atomic agency that detailed major progress Iran had made in diluting most of its stockpile of medium-enriched uranium, nuclear fuel that the West has long feared could be converted relatively quickly into weapons-grade material. Getting Iran to dilute that uranium was perhaps the biggest single accomplishment of the interim deal struck last year, creating room for the current negotiations, which […]