Jeffrey LewisDPRK Test Tunnel

I can’t tell whether to irritated at Yonhap, the ROK Ministry of Defense, or both.  Read this:

North Korea is believed to have detonated a nuclear device in 2009 inside a mountain tunnel elaborately designed with several traps to prevent radioactivity from escaping, Seoul’s defense ministry said Monday, releasing video footage from its state-run television.


The four-part documentary film series aired on the North’s Korean Central Television in October 2010 shows a horizontal tunnel with three “traps” between nine “doors,” which are designed to block radioactivity and debris from escaping from the western tunnel. It was used for a second test in May 2009.



First, the film is not “documentary” in any sense of the word.  The film, The Country I Saw, is a melodrama with actors and sets. I wrote a little article for 38North about the film with my colleague Hanah Rhee, who kindly subtitled the interesting bits including the footage from the “nuclear test.”

As a bit of big-budget state propaganda, The Country I Saw provides fascinating look at how North Koreans see their nuclear and missile programs.

Whether the animations accurately reflect North Korean test preparations, however, is much harder to say.  The spiral test tunnel, as I noted at the time, shows more than your average art director might claim to know about containing underground nuclear explosions. (The Pakistanis claimed their tunnels ended in “fishhooks.”)  But other animations seem to be nonsense.  In other words, the footage is super interesting, but hardly definitive.

All of which is context that should be included in the story.  Where could we find such context?  How about Sig Hecker and Frank Pabian? How would Yonhap know to call them?  Well, they stole a graphic from them.  On the left is an image from the Yonhap story (with Yonhap’s logo); on the right is the original graphic annotated and captioned by Frank and published at the Bulletin of Atomic Scientists.

Figure 4: North Korean television animation video-frame capture depicting what was asserted to be the tunnel layout and nine interior doors for containment of the 2009 nuclear test in North Korea, along with three blast and debris traps and a fishhook-like emplacement chamber (annotations in white were added by the authors). 
(Source: Screen capture from fourth episode of North Korean serialized drama called “Country That I Saw”, as broadcast from Korean Central Television, Pyongyang, via Satellite in Korean. The episode aired in September 2010. Yonhap News, Seoul, provided permission to use this image.)

Here is what Sig and Frank wrote at the time:

On September 8, 2010, Pyongyang Korean Central Television broadcast a partially animated dramatization of the 2009 test. Several of the graphics from that video have surfaced in the open literature, including the alleged layout of the test tunnel shown in Figure 4. The video appears to be a propaganda piece, intended to impress its citizens, to inform the international community of the great precautions North Korea claims to have taken to prevent radiation leaks from the test, and to help convince doubters that the explosion was indeed a nuclear test. Clearly, some aspects of this video have no basis in fact, e.g., the massive arched portal door shown in the animation bears no resemblance whatsoever to the 2009 test portal area’s hamlet-like appearance, which can be observed on commercial satellite imagery. In addition, the video shows a topographical map of what is presumed to be the test epicenter and seismic monitoring stations, but the mountain contours do not match the Punggye-ri site.

The tunnel layout shown in Figure 4 does, however, appear to have similarities to the described Pakistani tunnel at Ras Koh. It includes several flat S-shape and zigzag features, and a loop-around hook (e.g., “fishhook”) leading to the device emplacement chamber. Unlike the Pakistani tunnel, the North Korean tunnel is alleged to contain nine remotely operated internal isolation or blast doors and what we have identified as three blast anddebris traps that appear plausibly located to capture any blast debris. In contrast, the Pakistani Ras Koh Hills tunnel, in addition to the self-sealing fishhook feature, was reported to have been sealed by a mixture of sand and 6,000 bags of cement. Although the similarities we cite in some North Korean and Pakistani nuclear test practices do not constitute proof of collaboration, they give us concern that North Korea could have learned a lot from the Pakistanis.


  1. Bradley Laing (History)

    “wether to *be* irritated”

  2. Bruce Klingner (History)

    Jeffrey, obviously lots of speculation whether next North Korea test will be uranium or boosted plutonium. How accurately could intel sources determine remotely whether test is plutonium, uranium, or boosted? I seem to remember hearing we can sniff plutonium if it vents but can’t sniff uranium. I wanted to tap into the amazing expertise of you and your readers. Thanks

    • Jeffrey (History)

      My understanding is as a policy-interested consumer of technical information relating to radionuclide monitoring. So, by all means, get it from a real expert.

      But one should be able to tell from the composition of noble gas samples whether the bomb was plutonium or uranium. There are issues associated with atmospheric transport and mixing against backgrounds, but in principle it is possible.

      If containment is poor-to-nonexistent, and you get lots of radioactive particles, then nothing should be left to the imagination.

  3. Ara Barsamian (History)

    North Koreans will brag and tel us whether it was Plutonium or HEU.

    By the way, imploding HEU is much simpler than Plutonium; some of you may recall Nobel prize winner Louis Alvarez talking about dropping one subcritical piece of HEU from about a meter on top of another piece of HEU.

    As far as HEU implosion, a lot of HE (1 to 2 tons) instead of what we used in B53 (~150kg) will do very nicely and guarantee 20kT even with lousy symmetry and poor initiator…

  4. Anon2 (History)


    Let’s debate the data in a new thread of the test (magnitude 5.0 Richter), i.e. plutonium, HEU, boosted, not boosted. I am guessing that a magnitude 5.0 maps into a slightly bigger test than 2009, i.e. around 3 kT. This would be unlikely to be HEU or a boosted or thermonuclear device??


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