Iran fortifies underground uranium cache, hindering removal

Iran has significantly fortified the underground sites holding its stockpile of highly enriched uranium in recent weeks, complicating diplomatic efforts to secure a deal requiring its removal. According to U.S. intelligence assessments, Iran has deliberately collapsed tunnels and rigged entrances with explosive mines at facilities, primarily at the Isfahan nuclear complex, where an estimated half-ton of near weapons-grade material is stored.

The new security measures have made accessing the uranium far more difficult and dangerous than it was just a month ago. This development introduces a major logistical hurdle for any potential agreement under negotiation between Washington and Tehran, which reportedly includes a provision for Iran to surrender its stockpile for destruction and removal from the country. A senior U.S. administration official said recently that the two sides are moving closer to a deal, with the material to be destroyed on-site before being taken out of Iran.

However, the physical fortifications raise serious questions about the feasibility of retrieving the uranium and verifying its complete inventory. Scott Roecker, a former head of the U.S. National Nuclear...