Nuclear security

Intelligence Chief: We Don’t Know If North Korea Has a ‘Boosted Bomb’

A boosted nuclear weapon is sometimes described as an intermediary point between a fission bomb and a much more destructive hydrogen bomb.

The seismic data from the Jan. 6 underground bomb test, which produced a 5.1-magnitude quake, indicates that the yield was about 6 kilotons,(possibly 10) in line with a conventional fission device, not a thermonuclear bomb, which can have a yield between 15,000 and 50,000 kilotons.

On Monday, Director of National Intelligence James Clapper echoed what most other experts have said: “It was much more modest than they claimed,” he said. “It’s hard to say what they are trying.”

Some have argued that a so-called boosted bomb would represent a significant increase in North Korean capability. In a boosted bomb, fissile material such as plutonium (of which North Korea has a small stockpile) or highly enriched uranium is put into a fissile chain reaction. The reaction fuses deuterium and tritium, two hydrogen isotopes, that have been thrust into the bomb’s core.