North Korea could deploy thermonuclear weapon seven times more powerful than Hiroshima bomb

The 100 kilotons device would fall short of the hydrogen bomb that Pyongyang claims it has "perfected"

The mushroom cloud of the first test of a hydrogen bomb ,
An American hydrogen bomb is tested on an atoll in the Pacific Ocean in 1952. The North Koreans claim to be ready to detonate H-bombs, but outsiders are sceptical about these claims. Credit: Photo: Reuters

North Korea could deploy a thermonuclear weapon with seven times the power of the bomb dropped on Hiroshima in 1945 within five years, in a significant leap from Pyongyang's present arsenal, according to US experts.

The 100 kilotons device would fall short of the power of the hydrogen bomb that Kim Jong-un, the North Korean leader, claims his scientists have perfected, but experts agree that a weapon that utilises fusion fuels, such as deuterium or lithium, to dramatically boost the yield of a conventional fission explosion is potentially within his reach.

There has been renewed concern over advances in Pyongyang's nuclear programme after Mr Kim proclaimed on December 10 that his regime is now a "powerful nuclear weapons state ready to detonate self-reliant A-bombs and H-bombs".


Washington played down that revelation on the grounds that there is no evidence to support Mr Kim's claim, although a White House spokesman conceded: "We take very seriously the risk and the threat that is posed by the North Korean regime in their ambitions to develop a nuclear weapon."

But a device that builds on the nuclear tests that North Korea conducted in 2006, 2009 and, most successfully, in 2013, is a "technically plausible scenario", said Jeffrey Lewis, of the Monterey Institute of International Studies.

In an article for 38 North, the website operated by the US-Korea Institute at Johns Hopkins School of Advanced International Studies, Mr Lewis says Mr Kim's comments are "obviously" propaganda, although he admits that "the idea of a North Korean H-bomb has been floating around for a bit".

One step in the progression from the nuclear devices that the North has already tested and a hydrogen bomb would be fusion fuels to enhance the destructive power of a fission explosion.

"Pretty much every country that builds nuclear weapons looks at using fusion fuel to boost the yield of a device", he said. China, for example burned lithium-6 in its third nuclear detonation, less than two years after its first nuclear test in 1964.

Joel Wit, editor of 38 North, told a press briefing in Washington on Wednesday: "Our projection is that by 2020, they could reach the deployment of a single-stage thermonuclear weapon.

"They could also make significant progress on the two-stage, the larger-yield nuclear weapon", he added.

The 2013 conventional nuclear test had an estimated yield of seven kilotons and advances since then have probably raised the yield to at least 10 kilotons, he said.

A two-stage weapon will have yields that measure in the megatons.

North Korea's problem is going to come when it has to test the theoretical advances that it has made, Lance Gatling, a defence analysts and president of Nexial Research Inc.

"This would be a significant advance in terms of complexity and the materials that would be required," he told The Telegraph. "And if they do set something of that scale off, then the world will know about it because there will be plenty of indicators of a blast that significant.

"But from a political standpoint, any time you have a madman with a nuclear weapon – large or small – it needs to be a cause for concern", he said.