Iran’s underground nuclear sites not immune to U.S. bunker-busters, experts say
Western spy agencies for years have kept watch on a craggy peak in northwest Iran that houses of one the world’s most unusual nuclear sites. Known as Fordow, the facility is built into mountain bunkers designed to withstand aerial attack. Iran’s civil-defense chief has declared the site “impregnable.” But impregnable it is not, say U.S. military planners who are increasingly confident of their ability to deliver a serious blow against Fordow, should the president ever order an attack.
In arguing their case, U.S. officials acknowledged some uncertainty over whether even the Pentagon’s newest “bunker-buster” weapon — called the Massive Ordnance Penetrator, or MOP — could pierce in a single blow the subterranean chambers where Iran is making enriched uranium. But they said a sustained U.S. attack over multiple days would probably render the plant unusable by collapsing tunnels and irreparably damaging both its highly sensitive centrifuge equipment and the miles of pipes, tubes and wires required to operate it. “Hardened facilities require multiple sorties,” said a former senior intelligence official who has studied the formerly secret Fordow site and agreed to discuss sensitive details of U.S. strike capabilities on the condition of anonymity. “The question is, how many turns do you get at the apple?” U.S. confidence has been reinforced by training exercises in which bombers assaulted similar targets in deeply buried bunkers and mountain tunnels, the officials and experts said.
Yet, ultimately, the ability to destroy the Fordow does not depend on whether a bomb physically penetrates the cavern where Iran’s centrifuges are operating, several analysts said.
“There are good outcomes short of destroying” the centrifuge hall, Cordesman said in an interview. Strikes against more accessible targets — from tunnel entrances and air shafts to power and water systems — can effectively knock the plant out of action. Repeated strikes will also make Iran fearful of attempting to repair the damage, he added.
Other analysts stressed the particular vulnerability of centrifuges, machines that spin at supersonic speeds to purify uranium gas into the enriched form usable in nuclear applications. Almost anything that upsets delicately balanced machines — from shock waves and debris to power disruptions — can render them useless, said one former Pentagon official who also requested anonymity in discussing potential Iranian targets.
“If you can target the one piece of critical equipment instead of the whole thing, isn’t that just as good?” the official said. “Even by reducing the entrances to rubble, you’ve effectively entombed the site.”