Nuclear security

U.S. Nuclear History Offers Clues to North Korea’s Progress

The destructive force of that single hydrogen device turned out to be far greater than all explosives used in World War II, including the atom bombs dropped on Hiroshima and Nagasaki. The blast, code-named Bravo, was 1,000 times more powerful than the Hiroshima bomb. It was the nation’s most violent thermonuclear test ever.

But as Einstein foretold, the amount of matter that Bravo converted into energy was mind-bogglingly small — on the order of 1,500 grams, or about three pounds.

Few experts think North Korea will get close to mastering the secrets of true hydrogen bombs any time soon, if ever. But they cite a range of evidence suggesting that the isolated nation is now working hard to raise the destructive force of its nuclear arsenal with thermonuclear fire.