Nuclear security

Uranium Provides New Clue on Iran’s Past Nuclear Arms Work

The Obama administration has concluded that uranium particles discovered last year at a secretive Iranian military base likely were tied to the country’s past, covert nuclear weapons program, current and former officials said, a finding that contradicts Tehran’s longstanding denials that it was pursuing a bomb.

Traces of man-made uranium were found at the Parchin facility, southeast of Tehran, by investigators from the International Atomic Energy Agency, the United Nations’ nuclear watchdog, as part of an investigation tied to the landmark nuclear deal reached last July between Iran and global powers.

The Iranians have claimed that the site was used for developing and testing conventional weapons. The particles were the first physical evidence—on top of satellite imagery and documents from defectors—to support the charge that Iran had been pursuing a bomb there.