Here is a wild Tom Clancy - Steven den Beste scenario for dealing with the North Korean nuclear reactor - smart spears:
The reactor must be physically destroyed.
Blowing it up like the Israelis blew up Saddam Hussein's Osirak reactor in 1981 (with bombs dropped by F-16s) is obviously not the best way ? far too public, releasing a media firestorm. Far better to destroy it quietly, safely, stealthily and mysteriously.
With a spear. A steel rod 40 feet long and 4 inches in diameter, fin-stabilized, with a needle-sharp tungsten-carbide tip, equipped with a small JDAM guidance package including a GPS. It is non-explosive; there is no warhead.
You've heard of smart bombs. This is a smart spear.
You take a half-dozen of these Smart Spears up in a high-altitude bomber, like a B2 or B52, and drop them over Yongbyon at 50,000 or 60,000 feet. The Smart Spears have such a big sectional density that it will be like a vacuum drop ? with no wind resistance, they will be going faster than the speed of sound when they hit their target.
Going so fast and with almost no radar signature, the GPS-guided Smart Spears will punch through the Yongbyon reactor and keep right on going, burying themselves in the earth several hundred feet deep. The North Koreans won't know what happened, and all there will be is some holes in the ground ? plus a melted-down reactor....
Well. The rest of the article goes beyond the fringe, but this idea is intriguing. "Google" comes up with nothing on "smart spears" for me, although I suppose a lesser man would be delighted by the many links to Britney Spears (despite the unlikely association with "smart")
However, here are two articles about the GBU-28 bunker buster bomb already in the US arsenal. It uses explosives, but is probably heavier than the "Smart Spear". The GBU-28 is half as long but has three times the diameter - nine times the cross section times half the length equals roughly four times the volume for the GBU-28. Relative densities of steel and high explosives? Beats me. And might a smart spear be a steel pipe packed with spent uranium, thus allowing us the delightful irony of deactivating the reactor by dropping uranium on it? Where is Mr. Den Beste when we need him?
Anyway, if the GBU-28 is steerable despite its weight, I suppose the Smart Spear should be as well. Whether we can deliver it without attracting the attention of radar operators in North Korea, Russia, China, and South Korea seems to be problematic. Let's see:
Of the three active American heavy bombers, only the B-2A "Spirit" (or stealth bomber) is able to drop a variant of the bunker buster, called the GBU-37/B. America's other stealth aircraft--the F-117A "Night Hawk" light bomber and F-22A "Raptor" fighter--are unable to carry the GBU-28/B because of the planes' relatively short bomb bays.
If this were my fantasy, I might just take the explosives out of a GBU-37/b and let 'er rip. Obvious benefit - the rest of the system has already been tested. Whether the B-2A is stealthy enough, I have no idea. And going with the untested idea of dropping Britney Spears onto North Korea seems to introduce too many variables into the mix.