is much deeper than the reports I've seen.
from the Bulletin of the Atomic Scientists:
"There are currently two strategic versions of the B61. The B61-7, produced from 1985-1990, is a variable-yield gravity bomb for the B-52 and B-2. The B61-11 is an earth-penetrating weapon (EPW) for the B-2 with a "single yield," according to the NPR. Full-scale drop tests of the B61-11 were conducted in Nevada and Alaska, initially from F-16, B-1, and B-52 aircraft. After the B-2 Stealth bomber became operational in the Single Integrated Operational Plan (SIOP) in October 1997, it was chosen as the designated carrier of the B61-11. Of its three drop tests conducted in 1998, one involved two unarmed bombs dropped at an air force test range in the Yukon in Alaska. With its hardened steel case and nose cone, the B61-11s penetrated the frozen tundra to a depth of only two to three meters. Its conventional cousin, the 5,000-pound GBU-28, is said to penetrate about six meters of concrete.
The Robust Nuclear Earth Penetrator program, recommended by the latest NPR, could use the B61 (or B83) in an effort to build an earth-penetrating weapon that would be more effective than the B61-11. But a serious flaw in the concept of nuclear earth-penetrating weapons, even those with relatively low yields, is that they cannot penetrate deeply enough to contain a nuclear explosion and its deadly radioactive fallout. If used in an urban environment, such a weapon would cause thousands of casualties (see Robert W. Nelson, Science and Global Security, Vol. 10: pp. 1-20, 2002)."
http://www.thebulletin.org/article_nn.php?art_ofn=jf03norrisSame concern about fallout, just different data on penetration.
The Pentagon claims that a bomb that penetrated further would contain the fallout. Your data blows that away.
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