This article, about the B-53 thermonuclear bomb, misidentified the atomic test that rained radioactive fallout on Marshall Islanders living on Rongelap Atoll. It was the 1954 Bravo test, not the 1952 Ivy Mike test. The column also misstated the TNT equivalent of the bomb dropped on Hiroshima. The bomb was as powerful as 9 million tons, not 9 million pounds, of TNT.
The story of the B-53 'bunker buster' offers a lesson in managing nuclear weapons
Outside of the nuclear weapons communities, little notice was paid last week to the announcement that authorization had finally come through to begin dismantling the last of the minivan-size B-53s, the most powerful thermonuclear bombs ever deployed in the active U.S. stockpile.
A terror weapon if there ever was one, the 10,000-pound B-53 was designed to deliver an explosion of nine megatons. That is the equivalent of 9 million pounds of TNT, or 600 times the power of the bomb that destroyed Hiroshima.
Believe it or not, the last 50 B-53s were not retired from the active stockpile until 1997, and even then some were held as a "hedge" in case a new threat emerged.
The two nuclear bombs that destroyed Hiroshima and Nagasaki, termed military targets at the time, immediately killed more than 200,000 people and resulted in the deaths within five years of an additional 100,000. They won the war against Japan and none has been used since.
Why did the United States in the late 1950s and early 1960s need to build more than 300 B-53s? And why were as many as 50 kept through the late 1990s, while the U.S government built and deployed thousands of other nuclear weapons with less powerful warheads?
What did war planners have in mind? It's a tale that should have lessons for today as the Obama administration considers spending more than $180 billion over the next decade modernizing the nation's nuclear stockpile and replacing the intercontinental ballistic missiles, strategic submarines and aircraft that would deliver them.
There are steps being taken to win Republican votes for a treaty with Russia designed to reduce nuclear weapons. The lesson: Don't build more weapons than you need or could use.
From the start, the first B-53s built in 1962 were thought of as bunker busters, needed to attack deep underground shelters near Moscow that U.S. intelligence said were built to protect the Soviet leadership. The bomb had a rear compartment that contained five parachutes; they were designed to lay the bomb down softly on the surface so that its explosive power would send a shock wave through the earth to collapse the underground shelters, crushing the people within them. When production was halted in mid-1965, more than 300 B-53s had been built.
The test of the first U.S. thermonuclear fusion device took place in 1952 as a surface shot on Enewetak Atoll in the South Pacific. Called Ivy Mike, the bomb, like the B-53, had a yield of nine to 10 megatons.
Its radioactive fallout on Marshall Islanders living on Rongelap Atoll 140 miles away caused any number of health issues. They included miscarriages and thyroid losses among teenagers who played in the coral flakes that fell like snow on the beaches. The test shot even delivered low-level radiation to an atoll more than 300 miles away.