The last of the nation's biggest nuclear bombs, a Cold War relic 600 times more powerful than the atomic bomb dropped on Hiroshima was dismantled [on October 25]. Workers in Texas separated the roughly 300 pounds of high explosives inside from the special nuclear material - uranium - known as the pit. The work was done outside of public view for security reasons, but explosives from a bomb taken apart earlier were detonated as officials and reporters watched from less than a mile away. Put into service in 1962, when Cold War tensions peaked during the Cuban Missile Crisis, the B53 weighed 10,000 pounds and was the size of a minivan. The B53's disassembly ends the era of big megaton bombs, said Hans Kristensen, a spokesman for the Federation of American Scientists. The biggest nuclear bomb in the nation's arsenal now is the 1.2-megaton B83, he said. The B53 was 9 megatons. The 15-kiloton bomb dropped on Hiroshima, Japan, at the end of World War II killed as many as 140,000 people. Kristensen said the Obama administration shouldn't boast too much about dismantling the B53 when its arsenal of active nuclear warheads has been reduced by only 10 in the past seven months and Russia's arsenal has grown by 29. The two nations signed a treaty in December to reduce their arsenals.

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