Reports this week of progress at Iran’s Arak heavy water facility have raised concerns from U.S. officials that Iranian scientists are developing a second pathway for acquiring nuclear weapons. The regime already has an extensive network of facilities for enriching uranium, and has been systematically locking in critical infrastructure that it can use to race past the nuclear finish line.

The Arak facility would position Iran to create fuel for a plutonium-based nuclear bomb, of the kind that North Korea has repeatedly detonated.

Tasked with ensuring that nuclear material is not diverted for military purposes, the IAEA says Iran must urgently give it design data about Arak to allow it to monitor the site properly. “We are deeply troubled that Iran claims that the IR-40 heavy water reactor at Arak could be commissioned as soon as early 2014, but still refuses to provide the requisite design information,” Joseph Macmanus, the U.S. ambassador to the IAEA, told the 35-nation Board of Governors.

He cited IAEA rules that a member state must inform the Vienna-based U.N. agency about a nuclear plant, and give design details, as soon as it has decided to build one. Iran says it must only do so 180 days before bringing atom fuel to the plant. “Iran’s refusal to fulfill this basic obligation must necessarily cause one to ask whether Iran is again pursuing covert nuclear activities,” Macmanus said.

Macmanus’s comments come as the U.S. Treasury Department has blacklisted more than three dozen firms that it described as a global network of front companies backed by Tehran.

[Photo: Stybn / Wiki Commons]