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Document Friday: Can Iran’s Fordow Nuclear Enrichment Facility be “Bunker Busted?”

March 30, 2012

The Fordow Enrichment Center at Qom. A "hard and deeply buried target." Image from DigitalGlobe

Can Iran’s underground Fordow uranium enrichment facility, outside Qom, be successfully destroyed by bombing?  The short answer is: no one knows for sure.  But you can make a much more informed guess after reading the National Security Archive’s electronic briefing book, Underground Facilities: Intelligence and Targeting Issues.  The EBB, by Archive fellow Jeffrey T. Richelson, is an extraordinary collection of documents about underground bunkers… and how to “bust” them.

Richelson traces the challenge of identifying and destroying underground sites all the way back to the Nazi’s production of A-4 (V-2) rockets at Nordhausen.  Other notable underground structures include: the bunker where Kim Il-Sung conducted the Korean War; Cuban bunkers eventually used to store Soviet tactical nukes; underground air fields in China; a twelve-level tunnel system in Moscow allegedly including a secret metro rail to the Soviet leadership bunker adjacent to Moscow State University; a twelve-room complex inside a Baghdad cave, and a bunker 40 feet below a Qadhafi mansion that included an operating room, medical supplies, a generator, and living quarters.

A declassified 1951 CIA report describing Kim Il-Sung's underground bunker.

The EBB also presents documents that providing detailed analysis on how to detect and destroy these underground structures –including those constructed to protect the creation of WMD.

Definitely click over and read for yourself, but highlights include:

  • A 2001 report submitted to Congress by the Secretaries of Defense and Energy estimated that there were over 10,000 “potential hard and buried targets” in the world.  And that number will almost certainly increase.
  • A 1999  Defense Intelligence Agency twenty-year threat assessment stated that, “The proliferation of underground facilities (UGFs) in recent years has emerged as one of the most difficult challenges facing the U.S. Intelligence Community and is projected to become even more of a problem over the next two decades.”
  • To combat this challenge, intelligence agencies have established a number of “hard target” components: The National Reconnaissance Office’s Hard and Buried Targets Working Group; the National Geospatial Intelligence Agency’ Information and Underground Issues Division; the Defense Threat Reduction Agency’s Hard Target Research and Analysis Center.  Richelson writes that, “the most significant indication of the concern about underground facilities was the establishment, in 1997, of the Underground Facility Analysis Center (UFAC), which while subordinate to DIA also relies on participation from a number of other intelligence agencies – including the Central Intelligence Agency (CIA), National Security Agency (NSA), U.S. Strategic Command Joint Intelligence Operations Center, and the Air Force Technical Applications Center (AFTAC) – as well as the Defense Threat Reduction Agency (DTRA) and the U.S. Geological Survey (USGS). When it was established, UFAC had a staff of 20; by 2009 that number had grown to 240.”
  • The EBB has some very interesting information about how underground facilities are detected.  A 1999 report describes how the magnetic detection of machinery, heat shimmer, and laser vibrometry can be used (as well as HUMINT, COMINT, and SATINT) to detect hidden underground facilities.

So how do you destroy an underground facility (say at Fordow) after it has been discovered?  That is a tricky question to answer, but one document, Chapter 15 of the 2000 Joint Warfighting Science and Technology Plan, provides some clues.

A B52 drops a version of the Massive Ordnance Penetrator during a test at White Sands Missile Base.

If a country were to bomb the hardened site at Fordow (U.N. inspectors reported that some of the site’s bunkers were protected by up to 300 feet of mountain), first it would have to invade Iranian air space and evade Iranian air defense systems.  When Israel (and  Iran!) successfully bombed Iraq’s Osirak nuclear reactor, they were able to easily evade Iraq’s air defenses.  It’s unlikely Iran’s Surface to Air missile sites will be as unprepared as its neighbor’s were –even in the event of a sneak attack.  Furthermore, according to the Joint Warfighting plan, if “advanced radio frequency weapons are employed for functional defeat of [Iran’s] electronics [missile and detection capabilities],” the US planes may not be able to employ “precise three-dimensional delivery.”  I’m fairly certain this problem will have been solved by warfighters, but it is a concern worth mentioning.

And then there is the decision of which munition to use.  According to a Wall Street Journal report, the United States has spent $330 million to develop approximately 20 Massive Ordnance Penetrator (MOP) bombs, “30,000-pound titan[s] that can  be delivered by the country’s largest strategic bomber [the B-2 stealth bomber].”  (Personal aside: stealth planes are not completely undetectable by radar.  One was shot down by Serbian troops after being identified by a Soviet-era radar in 1999.  I’ve seen the wreckage of it at the Belgrade museum of aviation.)

The Journal reported that the MOP bunker buster is estimated to be capable of boring through 200 feet of dirt and rock before exploding.  This has led some to doubt that it could reach the “centrifuge room” at Qom, which is buried deep in into a mountain.   In a January interview with The Journal, Secretary of Defense Leon Panetta “acknowledged the bomb’s shortcomings against some of Iran’s deepest bunkers.”  He stated that the US was still “trying to develop” an improved bunker buster.  Squaring with this statement was a secret Pentagon request to Congress for 82 million more dollars for bunker buster funding.  The Journal reported, “The decision to sidestep the normal budget request process suggests the Pentagon deems the MOP upgrades to be a matter of some urgency.”

But a “dueling analysis” published by the Washington Post on February 29 –on the eve of Israeli Prime Minister Benjamin Netanyahu’s and Defense Minister Ehud Barak’s visits to the US– suggests that a bomb need not reach the “centrifuge room” at Qom to “deal a serious blow” to Iran’s nuclear ambitions.  The article quoted anonymous officials who argued that a “sustained US attack over multiple days would probably render the plant [at Fordow] unusable by collapsing tunnels and irreparably damaging both its highly sensitive centrifuge equipment an the miles of pipes, tubes, and wires required to operate it.”  If accurate, that still leaves the problem of avoiding Iranian air defenses for “multiple days.”  During the second Iraq War, the United States employed smaller, 500-pound BLU-122 bombs with mixed results.  It appears their relative ineffectiveness led to the development of the 30,000-pound MOD.

The final sentence of The Journal’s article states: “Israel has bunker buster bombs but the US hasn’t provided the MOP to any other country.”

How does 330 million dollars sound? From Gizmodo.

Due to the possible deficiencies of “conventional” ordnance, the Joint Warfighting Plan hinted that nuclear weapons may be necessary to “defeat” some bunkers. Reading between the lines, one could infer that, “some technical effords addressed in this chapter are being accomplished as part of a Department of Defense/Department of Energy defense pilot project for developing improved capabilities for defeat of hard and deeply buried targets” could mean, “we’re developing more nuclear bunker busters.”  (Read Bill Burr’s piece on the retired B-53 nuclear bunker buster, and marvel at the repeating cycle of weapons production and purchases.)

And there’s more unorthodox solutions.  A 2000 paper from the Air War College entitled, “Deeply Buried Facilities Implications for Military Operations,” suggested that placing a “suitcase-sized nuclear weapon” within the facility could do the trick.  (I wonder how the MEK and their American lobbyists would feel about that assignment.)  The Joint Warfighting report also suggested employing, “hypersonic weapons, energetic materials, and radio-frequency weapons” and emphasizes the need for “weapons that provide a robust lethality solution that is not dependent on having high-resolution target information,” which I read as, “having a really really really big bomb.”

Finally, –and this is the crux– after the target is bombed, the Joint Warfare report stresses the importance of being able to assess how much damage was actually done.  Tellingly, it recounts:

“During the [First] Gulf War, there were situations in which it was difficult to accomplish combat assessment –for example, following conventional munitions attacks on hardened aircraft shelters.  While it was obvious that the shelter had been penetrated, it was not possible to see inside the facility to determine if the aircraft had received critical damage.  In attacks conducted against buried bunkers, tunnels, or other hard targets, the problem is even more challenging.”

And so, after spending my day reading declassified documents about “bunker busting” (what a great day!), what strikes me the most is the importance of assessment.  An attack on the Fordow enrichment site at Qom could destroy the “centrifuge room” or it could damage the centrifuges and support equipment without destroying the centrifuges themselves.  Either way, the world –outside a handful of Iranian leaders and scientists– still would not know the true state of the enrichment program under the mountain.

If a tree falls in the woods and no one hears it, does it make a sound?  If the the Fordow nuclear enrichment facility at Qom is bombed and no one knows the extent of the damage, has the specter of a nuclear Iran really been diminished?

Think I’m wrong?  Tell me in the comments.

  1. Larry permalink
    April 9, 2012 3:06 pm

    How deep is Qom? If the first bomb doesnt succeed then just put another one right down in the hole left by the second. As to finding out what damage was done………satellite reconaissance would do just fine. If not an overfly. In any case we may not have a choice but to give these to the Israeli’s if they insist on bombing Qom and other Iranian facilities.

    • April 7, 2015 11:58 am

      I don’t mean to be rude, but you seem to have a cartoonish idea of how things work. There isn’t going to be a nice and tidy hole for the bomb to just fly down. The earth just collapses back in on itself. It may be rubble, but it’s still rock. Lots and lots of rock. It’s kind of reminiscent of the 9/11 conspiracy theorists that insist the Pentagon was hit by a missile because the “hole” in the building wasn’t shaped like an airplane.

  2. alex permalink
    September 20, 2012 12:21 pm

    Could not an ICBM be fitted with a ground penetrator? Even if it was just a tungsten rod, coming in at Mach 20 it’s going to send shock waves pretty deep.

    Alternatively, take out the entrances. Explosive drones could probably fly right into the tunnels.

    • April 7, 2015 12:49 pm

      Conceptually speak, that’s not a bad idea. Realistically speaking, there are two fatal problems. First, you do realize that an ICBM launched from FEW, Minot, or Malmstrom will have to cross over the Russian Federation (who are back to a hair-trigger posture because of Ukraine) the Chinese could also mistake it for an attack. Yes, trajectories can be computed after a certain point, but you’re betting the world on a prayer. The second problem is that the LGM-30 has a CEP (Circular Error Probability) of 200m. That means it can land anywhere within 200m of the intended target. Which is perfectly fine for a strategic nuclear warhead, but nowhere near good enough for this purpose.You might avoid the Russian problem by using an SLBM instead. But the CEP for the Trident II is 120m. Still not good enough. Terminal guidance at Mach 24 is a problem, to say the least.

    • April 7, 2015 12:53 pm

      Too low, too slow. Sitting duck for a SAM, even AAA or machine-gun fire could take the drones down. If the problem were that easy to solve, there wouldn’t be one by now.

      • April 7, 2015 12:58 pm

        And keep in mind there will be a high geopolitical cost to any attack on Iran. As in the US will be blamed for breaking our word and breaking the peace. Sanctions will most likely collapse, Iran will rebuild — deeper, stronger, and better defended. And they’d be guaranteed to pursue the bomb after such an attack. The truth of the matter is this: If Iran wants the bomb bad enough, sooner or later they will get it.

    • April 7, 2015 2:08 pm

      Alex, I was intrigued by your idea. So I had a friend here the University of Texas Jackson School of Geosciences run it through ane Earth impact simulator. The software was designed to asteroid impacts in mind, but the parameters are flexible enough that we were able to run it without problems. Here are the results:

      Distance from Impact: 10.00 meters ( = 32.80 feet )
      Projectile diameter: 2.00 meters ( = 6.56 feet )
      Projectile Density: 19300 kg/m3
      Impact Velocity: 8.00 km per second ( = 4.97 miles per second )
      Impact Angle: 60 degrees
      Target Density: 2750 kg/m3
      Target Type: Crystalline Rock

      Energy before atmospheric entry: 2.59 x 1012 Joules = 0.62 KiloTons TNT
      The average interval between impacts of this size somewhere on Earth is 0.6 years

      Global Changes:
      The Earth is not strongly disturbed by the impact and loses negligible mass.
      The impact does not make a noticeable change in the tilt of Earth’s axis (< 5 hundreths of a degree).
      The impact does not shift the Earth's orbit noticeably.

      Atmospheric Entry:
      The projectile lands intact, with a velocity 5.59 km/s = 3.47 miles/s.
      The energy lost in the atmosphere is 1.33 x 1012 Joules = 0.32 x 10-3 MegaTons.

      Crater Dimensions:

      Transient Crater Diameter: 98.1 meters ( = 322 feet )
      Transient Crater Depth: 34.7 meters ( = 114 feet )

      Final Crater Diameter: 123 meters ( = 402 feet )
      Final Crater Depth: 26.1 meters ( = 85.6 feet )
      The crater formed is a simple crater

      The floor of the crater is underlain by a lens of broken rock debris (breccia) with a —maximum thickness of 12.1 meters ( = 39.7 feet ).
      At this impact velocity ( < 12 km/s), little shock melting of the target occurs.

      The Good news: Your kinetic tungsten warhead penetrates 114 feet into solid rock, so a volley of several might work.

      The Bad news: The mass of such a warhead is over 80,000 kg, meaning you would need a Saturn V rocket to launch each one of them.

  3. Tom C permalink
    October 7, 2012 2:25 pm

    Frankly I think you are letting down America with all this talk of bombs and bunker busting,
    you guys really need to get out more and find out what the real world thinks who is the threat to world security at the moment it sounds like you.

  4. April 7, 2015 1:00 pm

    Also, the Iranians could cottagize the whole operation. Scattering the centrifuges and the other parts of the r&d and manufacturing all over the country in small, generic buildings. That’s how the Germans maintained their war production virtually unhindered by Allied strategic bombing.

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