“Broken Arrow” is a military term of art for a nuclear accident that doesn’t lead to a nuclear war. MacWilliams has had to learn all about these. Now he tells me about an incident that occurred back in 1961, and was largely declassified in 2013, just as he began his stint at DOE. A pair of 4-megaton hydrogen bombs, each more than 250 times more powerful than the bomb that destroyed Hiroshima, broke off a damaged B-52 over North Carolina.
