[John Valentine]

He said a strike would almost certainly cause the antiquated North Korean reactor, whose core is shielded by graphite, to burn out, removing a scientific record of past plutonium production.

Maybe its time to resurrect the "smart spears" idea: a kinetic energy weapon, the smart spear is a 16 foot long titanium tipped, satellite guided carbon steel spear dropped from high altitude that would strike the reactor at mach 2 plus, completely penetrate, and bury itself deep beneath the reactor.

[endthematrix]

To remain covert, I'd suggest a well placed charge to create a meltdown. Then push for IAEA (and the CIA of course) to go in and do their tests.