Shutting down North Korea's nuclear test site is trickier than it might seem.
A botched tunnel collapse could spread radioactive debris. Nuclear material might be buried, but accessible enough to be dug up and reused in a weapon. And even if all the testing tunnels are destroyed, North Korean engineers could simply dig a new one if they want to conduct another nuclear test.
Disarmament experts have raised many such scenarios after North Korea said over the weekend that it would use explosives to collapse the tunnels of its Punggye-ri nuclear test site next week.
With your current subscription plan you can comment on stories. However, before writing your first comment, please create a display name in the Profile section of your subscriber account page.