The Bunker Buster Fantasy
Amid all the talk about weapons of mass destruction, a curious bill
passed through the U.S. Senate Armed Services Committee, repealing a
ban on the research and development of low-yield nuclear weapons.
Scott Baldauf, “US May Stoke Asian Arms Race,” Christian Science
When the United States went to war against Afghanistan in 2001, the military believed that terrorists were hiding chemical and biological weaponry—perhaps even nuclear weapons—in sophisticated, deeply buried bunkers. Iraq dictator Saddam Hussein also was suspected of hiding in deeply buried bunkers, and of having underground caches for weapons of mass destruction.1
Bombs cannot destroy a buried target unless they can penetrate deeply into the earth without either detonating too soon or destroying the payload before detonation. Arguing that nuclear weapons may offer the only way to destroy deeply buried weapons caches or weapon manufacturing sites, the Pentagon pushed to develop small nuclear bombs to be mounted on deeply penetrating missiles.2 In 1997, the United States already had developed a so-called “bunker buster”—the “Low-Yield Earth-Penetrating Nuclear Weapon”—probably in contravention of U.S. policy to not develop new nuclear weapons.3
Bunker buster proponents explained that nuclear penetrator weapons could be used close to urban areas with minimal collateral civilian casualties, because the blast and radiation effects would be contained underground.4 Tests of the 1997 prototype did not support these assumptions, however. Dropped from an altitude of 40,000 feet, it penetrated only about 20 feet into dry earth. The current (2004) B61-Mod 11 U.S. nuclear earth penetrator weapon, a massive bomb with estimated 300-kiloton (Kt) yield, can penetrate only about 10 feet into frozen tundra.5 Penetration depths must be much greater to prevent an explosive fireball and deadly radiation clouds from reaching the surface.
Hundreds of underground nuclear weapons tests took place at the Nevada Test Site (NTS), near Las Vegas, between 1957 and 1992. They mostly detonated bombs in sealed excavations at depths scaled for containing varied bomb yields (see chapter 7, appendix 5). But many bomb test cavities failed to contain either the blast or the radiation. Figure A8.1 depicts the generalized sequence of events