Apparently North Korea has come up with a way of developing a clean nuclear weapon. Radiation-sniffing planes have so far come up with nothing.

Don't read too much into the lack of radiation. This was a very small explosion, underground, so it's not clear how much leakage there would have been.

One problem with the allegation that it actually could have been a conventional test is that it would have required a large amount of conventional explosives, which would have been visible to spy satellites before the test.

If it had the yield of 1000 tons of TNT, maybe it was 1000 tons of TNT. NK has a history of setting off Potemkin villages. They covered up their ICBM failure by shooting off six Scuds the same day. Perhaps the NK scientists themselves are afraid of ending up in a labour camp.

I found this on another website posted by someone familiar with nuclear sampling:

"If it is a well contained test, only isotopes of noble gases like argon and xenon are likely to surface through barometric gas transport along faults. But, then soil gas sampling in on-site inspection operations alone can detect them. And that not before 50 days after the test for a 1 kT yield. With no access to the site for such sampling, all efforts at radionuclide monitoring from the air amount to fishing expeditions. Simple radiation level measurements will tell nothing."

"They covered up their ICBM failure by shooting off six Scuds the same day."

There's no evidence that they fired those rockets to "cover up" the ICBM failure. It seems likely that they had always planned to launch a lot of rockets that day, regardless of the success or failure of their bigger rocket.

There is a danger when trying to belittle a madman
like Kim, he may do the next one above ground to prove he can.

See here.

Caution this is the print page of the article...
so it will try to print when you open it. I don't have the origional link.

Paul

One problem with the allegation that it actually could have been a conventional test is that it would have required a large amount of conventional explosives, which would have been visible to spy satellites before the test.

Not necessarily. Imagery satellites are in low Earth orbits that can only cover a given spot on the Earth for a few minutes a day. Unlike "24" or the terrible "Enemy of the State", it isn't possible to dial up imagery support any time, anywhere. Those satellites are very expensive and there aren't very many of them.

The North Koreans almost certainly know when those satellites are going to be in range (courtesy of China), so they can time their actions to reduce the chances of detection.

I remember reading somewhere, some years back (Scientific American, perhaps?) about the difficulty of verifying a complete nuclear test ban, and what a state might do in order to hide a low-yield underground test, or make it appear to be natural geologic activity (strangely enough, a minor natrual quake happened the next day in Japan, causing many to briefly think it was another North Korean test).

Who would've thought, at the time, that the reverse might happen, that a state might use conventional explosives to fake a nuclear test, precisely *because* of the political hassle that comes with being a 'demonstrated' nuclear-capable country?

Of course, if it was a nuclear 'dud' that produced far less than the intended yield (not hard to imagine, as it's even more difficult to make an *efficient,* intentional sub-kiloton nuke), we're forced to assume that, like their long-range missiles, they'll try again, and ultimately get better...

North Korea makes plenty of explosives for artillery shells, etc. They could have been moving them into place a few tonnes at a time for months.

Not so fast, Rand. It may have fizzled somewhat, but it's looking a bit more real than it was a few days ago ...

Which is more likely, attempting to emulate a failed nuclear test, or actually failing at a nuclear test?

They have fuel for weapons, so I have little doubt they attempted some sort of test. My only question is whether it was intentionally ultra-low yield (not that I think they're heading toward Teller-Ulam land, but who knows) or just a fizzle.

I also idly wonder if their nuclear scientists are actually heroes, and intentionally designed a dud. Presumably they'd only do that if they didn't expect a test, though.

The US has apparently detected radiation now. So much for the conspiracy theorists who thought it was conventional explosives. Go back to studying Roswell...

"Conspiracy theorists"?

"Roswell"?

Are you projecting?

So much for the conspiracy theorists who thought it was conventional explosives. Go back to studying Roswell...

We're hardly kooks. We made an early hypothesis based on the incomplete information (i.e no detected radiation) that we had available at the time. New evidence now indicates that there was a fission reaction.

Oh, I find it much easier to believe it was a real nuke that fizzled (all the more reason there would be so little external evicence, if it was detonated deep enough).

Remember, these are the same people who may have tried to launch a satellite in September 1998 (and never again?), whose downlink was around 27 mhz. In North America and some other loaces, that's in the middle of the Citizen's band, and it's hard to imagine a piece of the spectrum with more QRM (man-made interference) than that, to try to find and confirm a weak signal...

http://www.fas.org/spp/guide/dprk/index.html

...as opposed to the former Soviets, hardly always forthright themselves, but they wanted to be damn sure that everyone and his brother could recieve Sputnik-1...and its implications.

North Korea: 'Ambiguity R Us'

Only now apparently they have detected the radiation.

I'm eagerly awaiting the Blogosphere's retractions of false data... oh, yeah, you guys don't have to worry about that...