Joshua PollackDid North Korea Test a Nuke?

I’d bet on it. But a recent statement by the ODNI is raising all sorts of eyebrows:

The U.S. Intelligence Community assesses that North Korea probably conducted an underground nuclear explosion in the vicinity of P’unggye on May 25, 2009. The explosion yield was approximately a few kilotons. Analysis of the event continues. [emphasis added]

The statement does not explain the use of the hedge-word “probably,” but we can make an educated guess about it.

First, it is an established practice of the National Intelligence Council to use words like “probably” or “likely” to convey degrees of certainty about analytic judgments. See, for example, the fifth page of this memorable release from December 2007. Nothing’s ever completely certain.

Second, none of the usual telltale radionuclides were detected after the test, according to this and this. Although this phenomenon is not unheard of, it does at least admit the possibility that the seismic event actually involved a heapin’ helpin’ of conventional explosives, rather than a nuclear explosive.

But merely because it’s possible doesn’t make it plausible. This scenario was discussed at a recent scientific convention on CTBT verification in Vienna and basically dismissed.

One thing is (virtually) certain. If North Korea had been trucking 2,000 tons of TNT up a mountain and packing it into a deep hole, everyone would have noticed.


  1. bradley laing (History)

    June 17 (Bloomberg) — Japan said North Korea may be planning to launch another missile, a day after U.S. President Barack Obama called the communist country’s recent actions a “grave threat” to international security.

  2. bradley laing (History)

    SEOUL – CLOSE aides of North Korea’s likely next leader Kim Jong Un failed last week in their attempt to assassinate his eldest brother, who was once their father’s heir apparent, said a television report.
    Mr Kim’s plotters had eliminated the close aides of Mr Kim Jong Nam back in North Korea before making their move on the 38-year-old who resided in Macau, Korean Broadcasting System (KBS) of South Korea reported on Monday, citing Chinese government sources.

    —-This is so bizzare, i wish someone smarter than me could explain it.

  3. bradley laing (History)

    Kim Jong-il, North Korea’s dictator, has immersed himself in high culture for the last few days, directing a Tchaikovsky opera and attending some Chinese musical theatre. But South Korean officials hope he is not building up to a grand finale, trying to upstage their president, Lee Myung-bak, on his visit to Washington.

    —I do not want to over do these postings. But…assassination conspiracies, possible attempts to “upstage” South Koreas leaders by getting someone killed in a battle…or maybe setting off a third nuke test…I mean, wow, what a world.

  4. Guest

    With a medium sized truck carrying 7 tons this means 300 loads. Over, say, two years, this is less than one load every two days. Hardly eye-catching…

  5. Gridlock (History)

    OT sorry but Cryptome has a copy of “Mobile PAL Operations for Nuclear Explosives” document – plans for PAL work to be made mobile, thus reducing the need for shipment to/from PANTEX so much.

  6. Gridlock (History)

    Did anything ever get resolved (in Open Source terms at least) about that large, suspiciously timed explosion in North Korea about the time Il Duce’s train was passing by?

    Seems to me it went quiet, fast.

  7. Anon

    Assuming it was probably a nuclear test, what’s the probability it was a successful nuclear test?

  8. Andy (History)

    The IC is moving toward limiting confidence on inferred judgments with limited evidentiary basis. We saw the same thing with in the interview (now available on the DNI website) about the Syrian reactor (emphasis added):

    SENIOR INTELLIGENCE OFFICIAL 2: We told our President four things: This is a reactor; the North Koreans and the Syrians are cooperating on nuclear activities; the North Koreans and Syrians are cooperating on the construction of this reactor; and this reactor – its purpose – is to create fuel for a nuclear weapons program. Those are the things we concluded.
    Now, when you look at the body of evidence of those four sentences and begin to sort out how much of that is based on an overwhelming body of evidence as opposed to a more limited body of evidence and therefore more reliant on assessment, the fact that it was a nuclear reactor – absolutely high confidence; the fact of Syrian-Korean nuclear cooperation spanning a decade at an intense level, high confidence. At the time of the strike, fact of North Korean-Syrian cooperation in the building of that reactor, medium confidence that then got higher because of events, some of which we have alluded to in the briefing, okay. The fact that that material was going to be used for a weapons program – we believe that to be true, but because we did not have, as [Senior Intelligence Official 1] points out, additional clinical evidence of other activities, we could only give it a low confidence level. But you need to – and I think you understand what I’m trying to say. That’s not more or less sure; it’s just that it’s a way of communicating that for which you have a large body of evidence and that for which you may not.

    So I wouldn’t read too much into that one “probably.”

  9. Geoff Forden (History)

    Josh, Perhaps the most interesting side of this statement is the implication that the West has not detected any radionuclides. Strangely enough, that could be further evidence that it was a nuclear explosion if no venting crater is observed. After all, it is (according to Caging the Dragon) actually harder to contain conventional explosions that generate a ton of gas for each ton of explosive power than it is to contain a nuclear explosion. Somebody should examine recent photos of the test site to see if they can observe a venting crater. I also consider the fact that nobody saw the North moving 2000 TONS of conventional explosive into a cave to be absolutely convincing that this was a nuclear explosion.

  10. 3.1415 (History)

    DPRK is known to be very good in digging tunnels. TNT can be transported in tunnels to avoid detection. I guess that your article means that there is no reliable seismic method to distinguish a nuclear vs. conventional explosion. Is that right? Would the shock waves be quite different?

  11. thermopile

    Andreas Persbo tweeted the other day that the explosion seems to have occurred at about 800m.

    That seems pretty deep to me. Anybody know how deep, on average, the NTS underground tests were? I haven’t read “Caging the Dragon” yet.

  12. Yale Simkin (History)

    thermopile wrote:
    Anybody know how deep, on average, the NTS underground tests were?

    Excellent list is available here

  13. Andreas Persbo

    The depth is an educated guess from a well respected seismologist. He said that it could have been a disused mine. I want to stress, however, that it’s a guess.

    3.1415: No way of distinguishing a conventional and a nuclear explosion by looking at the waveform alone. However, sequenced conventional detonations leave telltale signs.

  14. Homer Williams (History)

    I claim no expertise in this area and post this only in the hope that it may contribute to the discussion.

    At a presentation at The Korea Society in New York on July 14, I asked General Walter Sharp, commander of the United Nations Command, Combined Forces Command, and U.S. Forces Korea, if there was any physical evidence that the North Korean test in May was a nuclear device. He quoted the “highly probable” response. He was also unwilling to estimate the size of the explosion.