How serious is the North Korean nuclear threat?
Kim has advanced his weapons programme but it remains unclear whether he can hit the US
Katrina Manson in Washington
DECEMBER 21, 2017
By his own standards, Kim Jong Un has had a good year. At the start of 2017, the Supreme Leader announced North Korea had entered “the final stage of preparation” to test launch an intercontinental ballistic missile. He kept his word and, three such tests later, he declared last month that North Korea has “finally realised” its dream of being a state nuclear force. Observers expect him to say in his coming new year’s address he has completed the nuclear weapons programme that underpins his leadership.
But although Pyongyang has launched its longest range missile to date and conducted its sixth nuclear test this year — a possible hydrogen bomb — the US is not so sure. US military planners already assume North Korea can land a missile in the US but intelligence assessments vary and defence secretary Jim Mattis says North Korea is still “not yet” a capable threat to the US.
This is what we know about how much North Korea’s nuclear programme has achieved to date, whether its missiles can reach the US, and what it still has to master.
Is North Korea a nuclear power?
Yes. North Korea has produced plutonium and enriched uranium for years and has conducted six nuclear tests deep within its own mountains. Siegfried Hecker, a US scientist who has made seven visits to North Korean nuclear facilities, where he was once handed a hot jar of plutonium as proud proof, estimates the regime today has 25-30 nuclear weapons, each one potent enough to destroy a city. A leaked intelligence report puts the number closer to 60.
Has North Korea developed a hydrogen bomb?
It’s not clear. US officials say North Korea may have detonated its first hydrogen bomb in September. This two-stage fusion explosion relies on plutonium or uranium fission as a trigger, delivering far greater explosive impact up to — theoretically — a thousand times the strength of the atomic bomb dropped on Nagasaki in 1945.
Experts were struck by the much larger seismic impact of September’s underground explosion than previous atomic tests, with some saying it was akin to four Nagasakis. “At that yield it most likely was a two-stage thermonuclear device,” said Mr Hecker, adding it could be a “boosted” fission bomb rather than fusion explosion.
North Korean officials this year threatened to conduct a live nuclear test over the ocean — known as an atmospheric test — although Mr Hecker believes this is “an empty threat” because of the high risk of US retaliation.