Huge Bomb Test June 2nd

A few weeks ago Seymour Hersh reported in the New Yorker that many in the Pentagon were upset that the Bush Administration wouldn't remove using a tactical nuke against Iran from consideration. The reason they wanted to do so was to get at Iran's nuclear test facilities which apparently are far underground and hence protected from all but the largest bombs. So the question is, how protected are they?

Usually to find out such things engineers run tests, in this case the test is called Divine Strake. It's to happen on June 2, 2006 in Nevada. Now testing nuclear weapons, even tactical nuclear weapons, is something frowned upon by the world. As near as I can tell the closest thing to a ban on nuclear tests is the Comprehensive Test Ban Treaty which the US and others have not ratified. But we don't want to look too bad, so instead we'll just test "700 tons of ammonium nitrate and fuel oil (the equivalent of 593 tons of TNT)".

So you might be saying, well wait, if it's just testing conventional weapons, what's wrong with that? The reason is that 700 tons is big, really big. " The test would be the largest controlled conventional blast in military history and the biggest overall weapons test since the Cold War. Its explosion would create a 10,000-foot mushroom cloud and shake the surrounding earth at roughly 3.1 to 3.4 on the Richter scale while gouging a 36-foot-deep crater." It's apparently to see how tunnels and underground structures would be damaged in such a blast.

Still, what's wrong with that? According to this Washington Post article, Bush is committed to the nuclear test ban and "The test is aimed at determining how well a massive conventional bomb would perform against fortified underground targets." (This article also says the 36 foot deep hole is what the bomb will be set of in, not what it will gouge out.) So not much is wrong.

However this article from Worker's World (which I've never heard of) calls the test a Pentagon end-run around nuke test ban. It says the Pentagon budgets says Divine Strake would “develop a planning tool that will improve the war fighter’s confidence in selecting the smaller proper nuclear yield necessary to destroy underground facilities while minimizing collateral damage.” It then says that as of April 10, the DoD changed it's tune and says the test is just for conventional weapons. The article also says "The B-2, with its immense bomb bay, can only carry a weapon of some 40 tons." (And I'm not sure about that, the wikipedia page for the B-2 says "20 tons of 500 lb class bombs". So the test is for a conventional bomb we could not deliver to the target.

Doug Bruder is " director of the counter-weapons of mass destruction program for the Defense Department's Defense Threat Reduction Agency (DTRA)", the group sponsoring Divine Strake. The Las Vegas Sun quotes him as saying: "The detonation could simulate 'a number of weapon concepts'...It could be nuclear or advanced conventional...A charge of this size would be more related to a nuclear weapon." He also said: "There are some very hard targets out there and right now it would be extremely difficult if not impossible to defeat with current conventional weapons. Therefore there are some that would probably require nuclear weapons."

Hearing this, Rep. Jim Matheson (D-UT) is upset: "Officials who say they are using this Divine Strake test in planning for new nuclear weapons seem to be ignoring congressional intent about no new nuclear weapons, and that concerns me." Sen. Harry Reid (D-NV) is okay with the test because James Tegnelia, director of the Defense Threat Reduction Agency, said the test had nothing to do with development of a nuclear device.

globalsecurity.org (who I've also never heard of) has this detailed description of Divine Strake. "The DIVINE STRAKE full scale test is planned to be a large-yield, buried burst detonated at the Nevada Test Site. Divine Strake would appear to be associated with the Robust Nuclear Earth Penetrator RNEP, or possibly the B61-11 Earth-Penetrating Weapon, a fact that is obscured in most press coverage"

It was this Bunker Buster page on globalsecurity.org that gave me enough background info to understand all of this. Destroying something deep underground is difficult. Conventional weapons dropped from planes are limited in their destructive capabilities. Nuclear weapons of course affect larger areas and "cannot be engineered to penetrate deeply enough to prevent fallout. Based on technical analysis at the Nevada Test Site, a weapon with a 10-kiloton yield [Hiroshima was about 15 kilotons] must be buried deeper than 850 feet to prevent spewing of radioactive debris. Yet a weapon dropped from a plane at 40,000 feet will penetrate less than 100 feet of loose dirt and less than 30 feet of rock. Ultimately, the depth of penetration is limited by the strength of the missile casing. The deepest current earth penetrators, the B61 Mod 11 [a nuclear bomb], can burrow is 20 feet of dry earth. Casing made of even the strongest material cannot withstand the physical forces of burrowing through 100 feet of granite, much less 850 feet."

So what could this test be for? Well it could be testing what would happen if 18 B-2s dropped a full load of conventional bombs on exactly the same spot (probably not possible). Or it could be to see what effect a close to the surface small nuclear explosion would have on underground complexes, even though such a blast wouldn't contain fallout. Since the latter is what's in the 2006 budget request (p. 25) I'm going with that.

The sad fact seems to be that there doesn't seem to be a way of destroying a deep underground facility by dropping non-nuclear bombs. Since using nukes, even small ones, on non-nuclear capable countries would be politically evil, we had better find some other way of dealing with the problem, perhaps diplomacy or ground forces. Joy. Bush is right, his job is hard, but that's no excuse to do something stupid.