Did They Or Didn't They?

Jeffrey Lewis at Arms Control Wonk says we should know in a couple of days through radionuclide readings whether or not North Korea actually has the bomb. Turns out the French are leading the charge. Thus far, seismic readings suggest a half a kiloton explosion, which is apparently quite small for a nuclear explosion of the sort North Korea allegedly would detonate. See also the various North Korean statements here.

Why is this man smiling?