North Korea’s nuclear declaration: what it does and does not mean

– How significant is closing Punggye-ri?

All but one of the North’s nuclear blasts have been carried out under Mount Mantap at the Punggye-ri nuclear test site in the northwest of the country, with landslides and earthquakes after the last blast leading to speculation it was suffering from “tired mountain syndrome”.

Closing Punggye-ri does not preclude the use of other locations, or even atmospheric nuclear tests, MIT political scientist Vipin Narang pointed out.

But David Albright of the Institute for Science and International Security said the declared intention to “transparently guarantee” the end of testing was highly significant, opening the way to the US seeking access to the site.

“Transparency is critical and a key concession, if sincere.”

– How powerful is Pyongyang’s arsenal? –

Monitoring groups put the size of Pyongyang’s sixth and last atomic blast in September at 250 kilotons — 16 times the size of the US bomb that destroyed Hiroshima in 1945 and the kind of yield generated by a hydrogen bomb.

In a 2016 defence white paper, Seoul estimated the North had 50 kilograms of plutonium — reportedly enough for about 10 bombs, and US estimates of its bomb numbers are said to be significantly higher.

The Hwasong-15 ICBM Pyongyang tested in November has an estimated range of more than 13,000 kilometres (8,000 miles), analysts say, bringing the whole of the US mainland within range.

There are still questions over its capabilities — it has not demonstrated targeting abilities, miniaturisation of a warhead, or the re-entry technology needed to survive coming back into the Earth’s atmosphere. But it claims to have mastered all three.

And whenever it holds a military parade, it puts scores of missiles and giant launchers on show rolling through Kim Il Sung square.