North Korea’s claim to have miniaturized a nuclear weapon to fit a ballistic missile is likely to be false, a London-based defense information provider said Wednesday.

The communist country had revealed a photo of its leader Kim Jong-un inspecting a silver sphere -- believed to be the device in question -- in front of the state’s KH-08 long-range missile. Kim directly stated that his engineers had succeeded in miniaturizing the nuclear warheads.

But Karl Dewey, a senior analyst at IHS Jane’s said it is unlikely that the silver figure is a thermonuclear bomb, also referred to as a hydrogen bomb, given its spherical shape.

“Thermonuclear weapons are multistage devices, and in modern weapons the need to place two separate stages together would result in a more oblong-like structure,” he said. “As such, the device on the table is unlikely to be a thermonuclear device.”

Dewey said the North’s claims can be separated into two components: whether the country succeeded in miniaturizing a weapon and whether they have successfully miniaturized a “thermonuclear weapon.” He said the photos indicate they made an object small enough to mount onto the KN-08, although the validity of such a claim itself is questionable considering the country’s history of displaying mockups to deceive outsiders.

Assuming that silver object is a legitimate device, Dewey said that it is likely to be a simple implosion weapon, or a “boosted weapon.”

A boosted weapon, or boosted fission weapon, adds hydrogen isotopes that fuse and release neutrons upon an explosion to make the weapon more efficient. The institute had speculated that this was what was detonated in the North’s Jan. 6 nuclear test, which Pyongyang had claimed was a hydrogen bomb test.

“It is possible, but unconfirmed that claims of an ‘H-bomb’ (by North Korea) refer to these hydrogen isotopes,” Dewey said.

Being the most secluded state in the world, the exact arsenal of North Korea remains a mystery. Pyongyang has been boasting that it could strike the U.S. mainland with a nuclear missile, but authorities in Seoul and Washington have expressed doubts of such claims.

(minsikyoon@heraldcorp.com)