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Yet another flow-forming machine has appeared on North Korean television. (Here are the earlier ones.) This one is shown being exhibited to Kim Jong-il, late in his life by the look of him.

If you’re coming late to this story, a flow-forming machine (or flow-forming lathe) is a specialized machine tool. It has a handful of uses, but among them is forming the maraging-steel rotors that experts believe are used in North Korea’s gas centrifuges. Since gas centrifuges are used to enrich uranium, that makes flow-forming technology pretty interesting in these parts.

It’s unclear where this display took place; other than the floor, the location is obscured by a tent of translucent plastic sheeting. Was it placed there to shield the machine from onlookers? To shield the location from the camera accompanying Kim Jong-il? To keep the machine clean or help regulate its temperature during operation? Or perhaps some other reason? It’s hard to say.

Above, we see KJI in front of a control panel, gazing at something while an official gives an explanation. Now, here’s what he was gazing at:

This machine appears similar to the one Kim Jong-un viewed in 2013, but is not identical.

* * *

The presence of a variety of flow-forming machines inside North Korea is no longer any kind of news. Scott Kemp identified one shown to Kim Jong-il at the Kusong Machine Tool Plant in September 2006, and another shown to Kim Jong-un at the Kanggye “Tractor Factory” in June 2013. Jeffrey Lewis and Amber Lee put this development in the context of North Korea’s efforts to produce CNC machine tools at home. Yours truly identified at least three generations of flow-forming machines inside North Korea. David Albright and Olli Heinonen confirmed the identification, while observing that we don’t know where all of the machines were made. (I continue to suspect that the machine shown at Kusong may have been a prototype produced there. Of course, when it comes to making centrifuge rotors, where the flow-forming machines might have been built is beside the point.)

The bottom line remains the same: despite the best efforts of the international community, North Korea has gained access to some very interesting, sensitive technology. We knew that already, but now perhaps we know it just a little moreso.


What this week’s Worldwide Threat Assessment of the US Intelligence Community said about North Korea was stark but hopefully not too surprising: its nuclear and missile programs ”pose a serious threat to the United States and to the security environment in East Asia.” The North Koreans are forging ahead, restarting the graphite-moderated reactor at Yongbyon, expanding the enrichment facility there, and taking steps toward fielding the KN-08 road-mobile ICBM.

(See p. 6 of the prepared text.)

No limitations on North Korea’s nuclear program are currently in place and no negotiations are underway toward this end — in noticeable contrast to the situation in Iran. Earlier this month, I took a stab at explaining why there has been no movement in this direction in over a year’s time, since before Pyongyang’s February 2013 nuclear test.

The following article was originally published in RUSI Newsbrief (Vol. 34, No. 1, January 2014), at It appears here with the gracious permission of the editors at RUSI Newsbrief.

Nuclear Diplomacy with North Korea: Over Before it Began?

Joshua Pollack

Commercial space images published over the course of 2013 have revealed considerable activity at North Korea’s nuclear complex at Yongbyon. A new, ‘experimental’ light-water reactor project appears to be complete externally, and the previously disabled gas-cooled, graphite moderated reactor – the source of North Korea’s plutonium – appears to have recommenced operations in late August or early September. The roof of the new gas-centrifuge uranium-enrichment facility shown to researchers from Stanford University’s Center for International Security and Cooperation in November 2010 has doubled in area.

These changes suggest a growing distance between North Korea’s formal commitment to denuclearisation under the discontinued Six-Party Talks (with South Korea, Japan, China, Russia and the US) and the entrenched reality of its nuclear programmes. They correspond to Pyongyang’s declaration in April 2013 that it would ‘adjust’, ‘alter the uses’ of, and ‘restart’ the facilities at Yongbyon. According to the North Korean authorities, these moves support a ‘new strategic line’ of simultaneously developing both nuclear weapons and the North Korean economy.

After decades of stagnation, North Korea’s ability to advance its economy significantly seems doubtful, regardless of whether this occurs in conjunction with nuclear-weapons development. But a different sort of parallel process – simultaneously technical and diplomatic – is at work in North Korea’s nuclear policy. Both aspects respond to the Obama administration’s policy of ‘strategic patience’, which relies on enforcing and strengthening sanctions in response to successive tests of long-range rockets and nuclear devices.

On two tracks to nowhere fast

On the technical track, the expansion of North Korea’s nuclear military potential at Yongbyon seems calculated to demonstrate the impotence of sanctions, while signalling heightened dangers in the form of a growing supply of fissile material. If the restoration of the small gas-graphite reactor symbolises the persistent diplomatic stalemate, the enlargement of the enrichment facility indicates a deeper problem. North Korea’s efforts to place its gas-centrifuge programme on an indigenous footing gravely complicate any strategy for rolling back its nuclear capabilities (key components are previously believed to have been imported). Unlike reactors, the operation of gas centrifuges produces little, if any, technical ‘signature’ that makes such activity readily identifiable. If the key components and materials for the centrifuge programme are produced domestically, sanctions will lack bite, and the international community cannot be certain of the number, size or whereabouts of enrichment facilities in the country beyond Yongbyon.

Verifying the full extent of the enrichment programme was the same iceberg upon which the Six-Party Talks foundered in 2008. The visible expansion of the programme now hints at what might lie below the waterline. In the months to come, further glimpses might be afforded, perhaps through the type of unofficial visit to Yongbyon previously used by North Korea to advertise its capabilities.

On the diplomatic track, North Korea strives to keep China – its main trading partner and sometime protector – from aligning its policies too closely with those of the US. Over the longer term, Pyongyang seeks to turn the agenda toward the removal of economic sanctions and the conclusion of a Korean War peace treaty, presumably one that ends the US military presence in South Korea.

Bottoming out

Tactical manoeuvres dominate for now, with the US in particular seeking to minimise the risks inherent to any further engagement following the abrupt collapse of a limited understanding between the US and North Korea announced on 29 February 2012. This abortive ‘Leap Day Deal’ was to have halted activity at the enrichment facility at Yongbyon, with measures in place for the verification of both the enrichment freeze and the continued disablement of the gas-graphite reactor and the associated reprocessing facility. It was also to have imposed moratoria on nuclear tests and long-range missile tests. In return, the US was to have provided food aid as a humanitarian gesture, and – at least in the view of the North Koreans – the arrangement was to have led to a resumption of the Six-Party Talks, with priority given to its own preferred issues, including the removal of sanctions.

The sticking point in this deal proved to be rocketry. The US government insisted that the missile moratorium encompass the activities of North Korea’s space programme, seeing it as a cover for the development of intercontinental ballistic missiles. The North Koreans differed, and quickly announced an upcoming satellite launch. The unravelling of the progress made prior to this disagreement left Washington dissatisfied and apparently determined not to repeat the experience, while Pyongyang, for its part, has expressed openness to another attempt at talks, either for its own reasons or to satisfy demands from Beijing.

The low tide of diplomatic engagement between the two sides came at the end of August 2012, when the North Korean foreign ministry announced a new policy on nuclear development. A lengthy memorandum declared that unless the US chose to make a ‘bold and fundamental change in its cold war mindset’ and to abandon its ‘hostile policy’, North Korea would expand its nuclear arsenal ‘beyond the U.S. imagination’. After another satellite launch in December 2012, prompting condemnation by the UN Security Council in January 2013, North Korea went further, explicitly disavowing the September 2005 Joint Statement, in which it had unequivocally agreed to ‘abandon all nuclear weapons and existing nuclear programs’ – the core achievement of the Six-Party Talks. North Korea’s third nuclear test followed in February.

After the usual condemnations by the international community, Beijing pressed Pyongyang to withdraw from its maximalist stance. According to Xinhua, the official Chinese news agency, North Korean envoy Choe Ryong-hae told Chinese Politburo Standing Committee member Liu Yunshan in May 2013 that the North Koreans were ‘willing to accept advice from the Chinese side and carry out dialogue with relevant parties’. The following month, the North Koreans issued a statement renewing their public commitment to denuclearisation and stating their willingness to discuss the idea of ‘a world without nuclear weapons’ with the US, as well as their own issues of concern. During meetings in Beijing to mark the eighth anniversary of the signing of the September 2005 Joint Statement, North Korean Vice Foreign Minister Kim Kye-gwan reportedly expressed support for resuming the Six-Party Talks.

Meanwhile, the position of US officials has stiffened, especially concerning the production of fissile material. The US continues to insist on a package of nuclear freezes and test moratoria before returning to negotiations. Significantly, however, Washington is no longer willing to entertain a verified freeze on nuclear activities at Yongbyon alone. Now, if the freeze does not cover all such facilities, anywhere in North Korea, no proposal for renewed denuclearisation talks will be judged ‘credible and authentic’. The Obama administration does not wish to be drawn into high-profile talks that simply fill time before the next round of North Korean rocket and nuclear tests. Should Pyongyang voluntarily freeze uranium enrichment beyond Yongbyon, this gesture would be understood as a signal of seriousness.

In the deep freeze

Now, however, it is substantive diplomacy – and not enrichment – that is frozen. Shuttle diplomacy conducted in the autumn of 2013 by Wu Dawei, a Chinese foreign ministry official, brought the sides no closer. Instead, Wu’s visits to Pyongyang and Washington mainly yielded barbs in the official North Korean media, including the official, outward-facing news agency, KCNA, about President Obama’s vision of ‘a world without nuclear weapons’. In June, Pyongyang had identified this ‘proposal’ as a valid basis for negotiations, but soon began to dismiss it as hypocritical rhetoric.

Following the Beijing gathering in September 2013, where no official American or South Korean participants were present, the North Korean foreign ministry arranged meetings with former US officials responsible for policy on North Korea during the Clinton and Obama administrations, Stephen Bosworth and Robert Gallucci, to convey their desire to enter talks without preconditions. As if in reply, current senior US officials, including National Security Advisor Susan Rice, have expressed the administration’s position with greater bluntness. In remarks made at Georgetown University in November, Rice declared that, ‘Pyongyang’s attempts to engage in dialogue while keeping critical elements of its weapons programs running are unacceptable’. Speaking to the press in Beijing the following day, the State Department’s point man on the North Korean nuclear issue, Glyn Davies, underscored Rice’s point: ‘if we are to get back to talks, North Korea is going to have to cease its nuclear activities’. North Korea responded predictably, insisting that Washington’s ‘unreasonable’ and ‘absurd’ preconditions prevented a resurrection of the Six-Party Talks. It added that North Korea ‘will be compelled to steadily bolster deterrence’ in the face of continuing US hostility.

The Obama administration’s stance reflects a belief that activity at the Yongbyon complex primarily provides North Korea with something valuable to trade away for sanctions relief, a peace treaty, and other desiderata. It is no longer the beating heart of the nuclear-weapons programme. Thus Washington’s insistence that North Korea foreclose the option of covert uranium enrichment for the duration of negotiations is entirely understandable. It could be compared, in spirit, to the Joint Plan of Action agreed by the EU/E3+3 and Iran in November: a confidence-building measure that creates space for in-depth negotiations by removing the implicit threat to produce weapons-grade fissile material.

Measured by results, Washington’s principled stand looks less rewarding, however. North Korea, unlike Iran, already considers itself a nuclear-armed state, and is very unlikely to comply with demands for a blanket freeze. Instead, North Korea’s fissile-material stockpile appears set to expand, allowing the production of more nuclear devices if desired. Qualitative improvements to weapons-related technology can also be expected; commercial satellite images published online show continuing work at North Korea’s launch sites and its nuclear test facility. In October, a North Korean diplomat at the UN reiterated plans for additional satellite launches. In late December, a high-ranking Korean Workers’ Party official, Kim Yong-nam, remarked that Kim Jong-un, the country’s third-generation leader, would ‘display the dignity’ of the country in space – an act North Korea typically follows, a few months later, with a nuclear test. The ultimate goal of denuclearisation therefore appears to be growing more distant.

New North Korean nuclear exports also cannot be ruled out. In the past, North Korea has exported nuclear technology to Syria and Libya and exchanged know-how with Pakistan. Assuming customers can be found, future export activity might involve enrichment technology or even excess fissile material. While the North Korean nuclear programme continues unchecked by diplomacy, the pursuit of non-proliferation faces mounting risks.

 * * *


Earlier this week, State Department Special Representative for North Korea Policy Glyn Davies visited the region again. The bottom line, as he explained to the press in Beijing, remains the same, with a hint at “further pressure” on North Korea to bring them around:

[The United States and China] share an interest in getting back to Six-Party Talks as soon as possible. Here, the principal obstacle, and you all know this, has been the lack of not just interest, but meaningful steps on the part of North Korea to demonstrate that it understands that it has to live up to its obligations and its commitments, principally those it made back in September 2005, that’s encapsulated in the joint statement. And it’s, I mean, I’ve been at this job now over two years, and I’ve been struck with the…the lack of interest on the part of North Korea in meaningfully addressing this denuclearization issue, which is the principal issue that underpins the Six Party talks process. We haven’t seen any signs that they are willing to move on that, willing to take steps to address the concerns that we’ve had. What they’ve said are things like that they have…that they’re interested in coming back to talk without preconditions, which means that they’d like to talk about everything except their obligations to denuclearize. So this is of great concern to us. So of course, here in Beijing, the bulk of the time I spent in meetings with Chinese officials was about how best to move the process forward, get back to Six Party, convince North Korea, if necessary, through further pressure, that it needs to begin taking steps now and get back on to that, into that process of denuclearization.

The President’s 2014 State of the Union address, delivered the same day, made no mention of any prospects for nuclear diplomacy with North Korea.


Update | A video of the panel is now online.

Further update | February 13, 2004 | It’s yet another flow-forming machine inside North Korea.

Greetings from Seoul, where I’ll soon be speaking at the Asan Institute’s conference on North Korea. I’m joining a panel on North Korea’s nuclear capabilities. (Surprised?)

By now, readers of this blog probably have an idea of the role of flow-forming lathes in the making of maraging-steel rotors for gas centrifuges, and are aware of their presence inside North Korea. MIT’s R. Scott Kemp, followed closely by Jeffrey Lewis and Amber Lee of CNS, has blazed a trail on this subject. The short version is, these specialized machine tools are needed to make rotors for P-2 gas centrifuges. That’s the technology for uranium enrichment that North Korea reportedly received from A.Q. Khan of Pakistan in the late 1990s.

It’s the judgment of the Asan Institute that visual aids hurt more than help in a conference setting. Fair enough: PowerPoint often detracts from the quality of presentations. But sometimes, too, a few pictures are just what’s needed.

This Calls for a Blog Post

My presentation will describe evidence, based on research conducted with MIT’s Kemp, that North Korea has set about establishing domestic production for crucial components and technologies for gas centrifuges. The story involves much more than flow-forming machines; if you happen to be in Seoul, come to the conference on Wednesday morning to hear all about it. But the evidence for flow-forming machines is especially striking precisely because it’s visual. Words don’t quite say it. Thus this post.

After the jump: Photographs of not one, not two, but at least three generations of flow-forming machines inside North Korea.

But First, A Short Primer

Before getting into those details, you’ll want to know how to recognize a flow-forming machine. So here’s an arbitrarily selected picture from the WWW. (Not from North Korea in this case.) It happens to be from China, but that’s not important.

On the left, partly obscured by a CNC control panel, is the headstock. You can’t see much of it in this picture, but that’s where a series of spinning parts is located: a drive ring, spindle, and mandrel. The mandrel is a specially shaped component where the metal workpiece — the object being worked — mounts onto the machine. (Those appear to be “before” and “after” workpieces lined up on the right side of the photo above.) On the far end of the whole setup is the tailstock, which keeps the workpiece in place during operation.

In the center of the machine is where the magic happens. It’s a carriage equipped with rollers that passes over the rapidly spinning workpiece, working it into a thin-walled, elongated form. A typical flow-forming carriage has three rollers, resulting in the distinctive triangular form you see above. Notice, too, the hydraulics projecting from each roller, 120 degrees apart from each other. More than anything else, this carriage is the visual signature of a flow-forming machine.

Got it? Good. Now, let’s move on to the flow-forming machines that keep appearing on North Korean television broadcasts.

Kusong Machine Tool Plant, Sept. 2006

This machine, displayed during a Kim Jong Il guidance tour to the Kusong Machine Tool Plant, and first shown in these pages by Scott Kemp in June, appears to be a prototype. There’s no CNC panel. Dark-toned cables run on the exterior, connecting to an exposed hydraulic element. It might be North Korea’s first indigenously produced flow-forming lathe.

Here’s the non-computerized control panel:

In the background of the shot below appears the carriage, with exposed hydraulics and dark-toned cables at the top:

And now for something new.

Kanggye General Tractor Plant (Dec. 2009)

The “tractor plant,” which Lewis and Lee describe as a munitions factory (see more details about it here) received a Kim Jong Il guidance tour in late 2009. Not only can we see a flow-forming machine, but we can see the cylindrical shape of its mandrel, shown projecting through the carriage:

This machine appears to be more advanced than one seen at Kusong. It has a free-standing CNC panel, typical of up-to-date flow-forming lathes. The opening in the carriage is squared-off, not round. The one visible hydraulic element is of a different design. External cables are white and placed differently.

Note, too, that what appears to be a finished workpiece stands upright upon the machine in the background, next to the headstock.


Kanggye General Tractor Plant (June 2013)

It was Kim Jong Un’s own televised guidance tour to the “tractor plant” that occasioned the Kemp post. Here again is what we can tentatively call the third generation of North Korean flow-forming technology, as it appeared at the Rodong Sinmun website (via North Korea Leadership Watch):

Notice the enclosed hydraulics, cabling, and other details that distinguish the machine from the one displayed in Dec. 2009.

Not only was this still picture of the “3rd-gen.” machine shown in the newspaper, but it appeared on television, too. And in the television broadcast, the very next image was this other flow-forming machine:

It could be the same machine as the one photographed at Kanggye in Dec. 2009. Notice what appear to be a pair of historical markers on the headstock.

The Bigger Picture

Like Kemp or Lewis and Lee, I cannot confidently assert that some or all of these specific machines have been producing centrifuge rotors. The metal cylinder shown standing on the flow-forming machine at the “tractor factory” in Dec. 2009 might be something else, perhaps part of a weapons system. It remains to be seen.

Clearly, though, North Korea has these kinds of machines, which are important for making maraging-steel rotors for gas centrifuges. These photographs represent just one (visually striking!) part of a larger body of evidence indicating that the North Koreans have set out to master, and perhaps have mastered, domestic production of crucial centrifuge-related components and technologies.

This bigger picture may help us to understand the surprising appearance of the Yongbyon centrifuge enrichment plant in late 2010. It also may help to explain how it is that North Korea lately appears to have doubled the floor space there.

Interested in the rest of the story, beyond just flow-forming machines? See you this Wednesday morning at Asan.


Back in 2011, Jeffrey published the first of what should have been many “roundup” posts: posts that would offer an overview of the “arms control, disarmament and nonproliferation universe.” Sadly, Read Behind never became a regular feature, and the experiment faded into this blog’s collective memory. However, with so many arms-control blogs out there, in addition to various news sources, some of them slightly off the beaten track, we think it might be useful to collect some of the week’s more interesting articles and serve them up for your reading pleasure. That’s one of my roles in the blog — Harry Halem, your new “wonk-tern.”

Now, on to this week’s articles. For some reason, the main theme this week seems to be North Korean missile and nuclear capabilities and U.S. missile defenses.

All Things Nuclear | David Wright reviews North Korea’s missiles… except for the KN-08 ICBM, so often discussed at ACW. The Pentagon has drawn a connection between that missile and the decision to expand the missile defense deployment in Alaska.

FAS Strategic Security Blog | Hans Kristensen reveals that the United States’ nuclear war plan has been updated recently. His guess as to why is as good as anyone’s.

38 North | Jeffrey Lewis and Nick Hansen discuss images of new construction at the DPRK’s plutonium production reactor in Yongbyon. Not mentioned: Supreme Commander of the Korean People’s Army Kim Jong-un (not quite as good as Guiding Star of the 21st Century, but we’ll roll with it) ordered the restart of the Yongbyon enrichment plant. When did it stop?

The Diplomat | Richard Weitz says that missile defense can strengthen ties between nations. RIA Novosti proves his point, sort of.

Washington Post | Walter Pincus says that nuclear deterrence works on everybody. Good to know.

The Diplomat (again) | Robert Farley says accidental wars are rare, but not so rare that he sounds comfortable.

Bloomberg | In response to North Korean missile moves, the U.S. is redeploying THAAD to Guam.

Asahi Shimbun | In an additional response to North Korean missile moves, the U.S. is deploying Aegis to the vicinity of Guam and Hawaii. Aloha!

Asahi Shimbun (again) | Japan thinks America knows something that Japan doesn’t know about North Korean nukes. Why?

CS Monitor | Kim Jong-un is a man of many titles. Did they forget this one?

We look forward to discussion and debate on the issues raised.


Back in April, I asked how the Ground-based Midcourse Defense might be adapted in response to North Korea’s nascent (or embryonic) ICBM force. Thanks to Steven Aftergood of FAS, we now have the official answer. It’s included in the replies to Questions for the Record (QFRs) from a November 2011 hearing of the House Armed Services Committee. The hearing volume and the QFRs now appear at the FAS Secrecy News site.

The question from Rep. Doug Lamborn and the answer from Under Secretary of Defense for Policy James Miller appear below the jump.

Mr. LAMBORN. Do you agree with Secretary Gates who said at the Shangri-La Dialogue in Singapore in June, ‘‘With the continued development of long-range missiles and potentially a road-mobile intercontinental ballistic missile and their continued development of nuclear weapons, North Korea is in the process of becoming a direct threat to the United States.’’ And two weeks later he said, ‘‘North Korea now constitutes a direct threat to the United States. The president told [China’s] President Hu that last year. They are developing a road-mobile ICBM. I never would have dreamed they would go to a road-mobile before testing a static ICBM. It’s a huge problem. As we’ve found out in a lot of places, finding mobile missiles is very tough.’’ Do you concur with Secretary Gates’ statements? Was the question of a North Korean road-mobile missile factored in to the decision in 2009 to abandon the Third Site and the deployment of 44 ground based interceptors at the missile fields at Fort Greely and Vandenberg Air Force Base? If North Korea begins fielding an array of road mobile ICBMs, and if they proliferate this technology to Iran and other countries as in the past, what does such activity do to current judgments about the adequacy of the current inventory of GBIs?

Dr. MILLER. I agree with Secretary Gates’ assessment that North Korea constitutes a direct threat to the United States, as it does to our South Korean and Japanese allies. North Korea’s nuclear ambitions and continued development of long-range missiles remain a primary focus of the development and deployment of the Ballistic Missile Defense System (BMDS). The capabilities developed and deployed as part of the integrated BMDS protect the United States from the potential emergence of an ICBM threat from Iran or North Korea. To maintain this advantageous position, the Administration is taking steps to improve the protection of the homeland from the potential ICBM threat posed by Iran and North Korea. These steps include the continued procurement of ground-based interceptors (GBIs), the deployment of additional sensors, and upgrades to the Command, Control, Battle Management, and Communications system. Improvements to the Ground-based Midcourse Defense (GMD) system, in particular, will better protect the United States against future ICBM threats, whether from Iran, North Korea, or other regional actors.

In the future, if projections regarding Iran or North Korea change significantly, then the United States should reassess its baseline program and consider implementing some elements of our hedge posture.


By now everyone has seen the latest IAEA Iran report, GOV/2012/23. Among other bits that have drawn attention is paragraph 28, concerning swipe samples taken at the subterranean enrichment facility outside of Qom in mid-February. These samples “showed the presence of particles with enrichment levels of up to 27% U-235,” more than the level that’s supposed to be produced there. That’s highly enriched uranium, in fact.

Iran has told the IAEA that “the production of such particles ‘above the target value’ may happen for technical reasons beyond the operator’s control.” While that answer clearly isn’t too satisfying, is it plausible? Could be. I don’t pretend to know what actually happened that resulted in the presence of 27% enriched HEU where it shouldn’t be. But a set of possibilities that don’t involve an attempt at cheating can be discerned, and one or another of them may be reasonably likely. (Caution: wonkish.)

For starters, hidden in footnote 16 of the same report is a reminder of a previous episode of over-enrichment in Iran. It concerns the main enrichment hall at the Natanz facility, which isn’t supposed to produce more than 5% enriched LEU: “A small number of particles from samples taken in the cascade area continue to be found with enrichment levels of between 5% and 7.4% U-235… the Agency assesses that these results refer to a known technical phenomenon associated with the start-up of centrifuge cascades.”

That’d be the “time transient” described in Houston Wood and Stephanos Tongelidis, “Gas Centrifuge Cascade Study for Maximum Assays During Start-Up,” in Proceedings of the 47th Annual Meeting of the Institute for Nuclear Materials Management (2006). In plain English: UF6 gas is fed into a centrifuge cascade slowly at first. Because the centrifuges are doing their usual work on an smallish volume of gas during this time, that initial volume gets over-enriched. Before very long, though, it gets blended down to the target level by the introduction of the rest of the feed gas into the cascade. Thus the “transient” label.

Reflux Redux

The same phenomenon would occur if the operator slowed the feed rate for any reason at any time, not just at startup. The generic term for the condition of over-enrichment due to slow feed is “reflux.” An ACW commenter also observed back in Oct. 2010 that if Stuxnet accelerated the centrifuges beyond their normal speed, the results would look the same as a slowdown of feed.

Left unanswered is why traces would have escaped the cascade during a reflux episode. Normally, traces exit when opening the cascade, dumping its contents, withdrawing samples from it, or switching out a product container. Why do any of these things during the time transient or any other reflux episode? In that sense, the presence of the HEU traces isn’t quite “beyond the operator’s control,” but it seems to be a matter of carelessness. That’s a little surprising for a facility designed to operate just shy of the politically sensitive HEU threshold. Or perhaps not. As noted above, it’s not the first case of over-enriched uranium traces escaping an Iranian centrifuge cascade.

In this instance, Albright, Stricker, and Walrond of ISIS attribute the over-enrichment to an operator error involving the enlarged cascades at Qom; if the original feed rate used for 15-stage cascades was initially used with the new, 17-stage cascades, it would wind up being too slow, resulting in an “overshoot” of the intended product level. (More centrifuges, more separative work, not enough UF6 gas, basically. Call it reflux by default.) In this scenario, which ISIS considers “likely,” the operators might have discovered their mistake when withdrawing samples, which would have spread the suspect traces. Whoops!

I haven’t done the math, but it makes a certain sense. Then again, Iran started using enlarged, 174-centrifuge cascades to produce “up to 20%” enriched uranium at Qom on Dec. 14, 2011. Would the first suspect traces only have emerged a full two months later, on Feb. 15, 2012? No samples taken, containers switched, etc., before then? What’s more, Iran had already been trying out a few 174-machine cascades at Natanz. You’d think they would have worked out these sorts of issues. I suppose one never knows.

Unfortunately, there are always darker possibilities. Like cross-contamination from another, still-clandestine enrichment plant. But 27% enriched HEU is close enough to the “up to 20%” enriched material expected at Qom that this explanation isn’t exactly one that leaps out and whacks you over the head.

Long story short: don’t panic just yet.

Postscript. By now, this issue may have been overshadowed by the hardening of Iran’s negotiating position. In the best case, it will turn out that nuclear diplomacy is also subject to over-enrichment and time transients. Let’s hope for the best…


[Updates have been transposed to the end of the post. -Ed.]

Tal Inbar points out these photos from today’s military parade in Pyongyang.

More details after the jump.

Those are two three-stage missiles carried on large, eight-axle vehicles. YTN describes them as being about 18 m long and about 2 m in diameter. [Note: based on an examination of the photographs, the 2 m diameter figure does not appear to be accurate if the missile is 18 m long.]  That’s much smaller than the TD-2 — not bigger, as the Chosun Ilbo had claimed. (Really, who could imagine a mobile missile almost half the length of a football field?)

An earlier YTN broadcast, aired before the parade, called the new missile by the name KN-08. That report is summarized in English by AFP here.

Further reading: My article of last week at on the unveiling of North Korea’s ICBM. Here at ACW, a discussion of the implications for missile defense — or, depending on your point of view, lack thereof.

Update | April 15, 10:19 am. An alert reader points out this CCTV broadcast. Going by the serial numbers, there were more than two ICBMs on parade. I see five: 904830216, 901010212, 904830218, 904830215, and 901010418. [See also below. -Ed.]

Update | April 15, 11:10 pm. Here are a couple more views of the new missile.

Update | April 17, 2012, 10:50 pm. Thanks to alert reader “AP,” who found a video of the entire parade as broadcast on Chinese television, we can see that six of the new missiles were displayed at the end of the parade. All appear in the shot simultaneously at 68:39.

Update | April 17, 2012, 11:59 pm. There’s been a fair amount of discussion in the comments of the source of the TEL. It’s pretty clearly a local hybrid built onto an extra-heavy chassis of the sort produced exclusively by the Hubei Sanjiang Space Wanshan Special Vehicle Co., Ltd., part of the China Sanjiang Space group, and a subsidiary of  the China Aerospace Science and Industry Corporation (CASIC), a state-owned enterprise. The most likely candidate appears to be Wanshan’s WS51200 chassis, which you can see in this nice illustration:

The CASIC website announced a sale worth 30 million yuan to an unnamed foreign customer in Oct. 2010. In August 2011, the Wanshan website announced a delivery of 122-ton WS51200s to an unnamed customer, dated May 17. “During the inspection of this delivery, the consumer was very satisfied with the vehicle and indicated the possible of the next cooperation.”

Thanks to all the commenters and lurkers who have unraveled this and other threads in this post.


Paul-Anton Krueger, who often seems intent on seizing the fallen mantle of Mark Hibbs, has advanced the story of Iran’s R&D activities at Parchin. His article in Saturday’s Sueddeutsche Zeitung – just in time for the talks in Istanbul — redeems this blogger’s foolish promise to post something about weaponization in Iran. It’s not an explosive story, but rather implosive: its subject is an alleged implosion test at Parchin in 2003, shortly before what’s believed to have been the suspension of Iran’s nuclear-weapons research. Whether and under what conditions the IAEA can visit the pertinent area at Parchin has been a subject of some dispute lately.

To make a long story short, Krueger reports that the research may have involved a neutron initiator. That’s a device that sparks a chain reaction in an implosion-type nuclear warhead. The subject isn’t completely new: the IAEA has reported on activities related to neutron initiators in Iran before. What’s new about this story is how it links three previously unconnected elements: implosion at Parchin, neutron initiation, and the assassination of nuclear scientists in the streets of Tehran.

Unfortunately for most of us, SZ appears only in German, and most of it never goes online. (You could always grab a copy during your next stopover in Munich, right?) In this case, there’s an abbreviated version of the story at the website. In German.

But guess what? You’re in luck. A translation of the complete article as it appears in the newspaper follows. Yeah. You’re welcome.

[start of translation]

Sueddeutsche Zeitung

April 14, 2012

Nuclear Grill-lighter

Iran has apparently tested a neutron initiator, an important component in a nuclear warhead

By Paul-Anton Krueger

Munich – A metal cylinder the size of a semi-trailer is expected to be the yardstick of Iran’s actual readiness to cooperate with the International Atomic Energy Agency (IAEA) in the coming weeks. During visits to Tehran, IAEA’s chief inspector Herman Nackaerts has repeatedly insisted upon being allowed to examine the chamber, which was probably built in the year 2000 at the Parchin military base, 20 km [12 mi.] southeast of Tehran. The IAEA suspects that Iran conducted research there for the development of a nuclear warhead. An inspection would show the world that Iran is cooperating with the investigation into what the IAEA delicately calls the “possible military dimensions” of its nuclear program.

Diplomats posted to Vienna where the IAEA is headquartered said that Nackaerts selected Parchin because he thought it would be relatively easy for Tehran to grant his team access there. The inspectors avoid making requests based on information from intelligence services, which Iran often dismisses as forgeries, if the IAEA cannot share the original documents. They have their own sources, having interviewed Vyacheslav Danilenko, a scientist from the former Soviet nuclear weapons laboratory Chelyabinsk-70, who is said to have helped Iran to build the cylinder, a test chamber inside which it is possible to experiment with high explosives, as well as the ignition mechanisms of nuclear weapons.

So far, the government in Tehran has resisted the request. Formally, Iran’s ambassador to the IAEA Ali Asgar Soltanieh has done so by insisting that Iran and the IAEA first establish modalities of inspection; in this connection, he has proposed a number of conditions that the inspectors find unacceptable.

However, there is apparently another explanation for Iran’s tough stance. Some diplomats, intelligence officials, and independent experts believe that Nackaerts has stirred up a hornet’s nest. They suspect that Iran used the cylinder to test a neutron initiator, a key component for a nuclear warhead. This experiment could have hardly any civil application. It would be difficult for the Islamic Republic to explain, since its Supreme Leader Ali Khamenei has rejected nuclear weapons as “un-Islamic” and maintains that they are interested only in the peaceful uses of nuclear energy.

A neutron initiator can be compared to a grill-lighter: just as it kindles the fire in a pile of charcoal, neutrons initiate fission in a nuclear warhead. The resulting chain reaction releases tremendous energy – a flash of light, deadly heat, and a tremendous blast, as well as radiation. However, for the ignition to work, several processes must occur within a split second in the proper sequence. In an implosion warhead, an arrangement of explosives and other components compresses a spherical core of highly enriched uranium so much that the metal becomes liquid. The neutron initiator, which is embedded in the center of the core, is simultaneously activated by the immense pressure.

The IAEA stated in its report of November 2011 that it has received information indicating that Iran has worked on such a neutron initiator, and may have tested it – but without establishing a direct connection to Parchin or the metal cylinder. However, a person associated with a Western intelligence agency told Sueddeutsche Zeitung that the IAEA has been presented with “solid evidence” that Iran had conducted this type of secret experiment there. Another source from a different Western country stated, “That’s just what Nackaerts suspects.” The IAEA declined to comment and merely referred to their reports.

The experiment – or experiments – would have taken place in the year 2003 under the direction of two Iranian scientists who were the targets of simultaneous bomb attacks in Tehran on November 29, 2010. An assassin on a motorcycle fastened a bomb to the car of physics professor Majid Shahriari during the morning rush hour, killing him. His colleague Fereydun Abbasi-Davani narrowly escaped an assassination attempt perpetrated in the same way, escaping from his car with his wife; both sustained injuries in the explosion. Iran accused Israel and the United States of being behind the attacks. President Mahmoud Ahmadinejad appointed Abbasi-Davani as the head of the Atomic Energy Organization of Iran and as one of his own deputies in February 2011.

According to intelligence-service information, the two scientists were at Parchin as project managers partly responsible for developing a special array of neutron detectors and installing it outside of the test chamber. It was used during an experiment to see whether the neutron initiator worked, releasing sufficient particles. In addition, a flash x-ray camera was installed that would capture the implosion of the test system in the metal cylinder at very high resolution. The data from both sources combined allow an assessment of whether the ignition mechanism for a nuclear warhead would work.

According to intelligence sources, two other scientists whose identities are known to the IAEA assisted Shahriari and Abbassi-Davani. Mohammed Reza Sedighi Saber, allegedly an expert from the Ministry of Defense, was entrusted with the simulation and computer-assisted analysis of the experiment. According to this information, Ali-Reza Mola Heidar, an expert on instrumentation, contributed to the development of the flash x-ray system and the positioning of the neutron detectors.

Since the experiment took place about ten years ago, it is unclear whether IAEA inspectors would find anything at Parchin. The neutron initiator itself consists of a few grams of nuclear materials. Traces of it would still be detectable, provided that the cylinder is still inside the building and has not been thoroughly cleaned. Although IAEA Director-General Yukia Amano did not confirm reports about cleanup work at the military base, he spoke in this context about “information about activity that has taken place there.”

Diplomats consider the clarification of the incident at Parchin to be very important, because the development of the neutron initiator is one of three areas in which Iran is said to have continued research and development activities after 2003. At that time, according to the estimate of the U.S. intelligence community, the country suspended its program for the actual creation of nuclear weapons. An inspection at Parchin “would be a very nice confidence-building step,” one European diplomat said, referring to the nuclear talks this Saturday in Istanbul.

[end of translation]

For further reading: The IAEA’s November 2011 report, GOV/2011/65, which contains a lengthy annex on “possible military dimensions,” is here. ISIS has published repeatedly about the events at Parchin (see here, here, here, and here). According to Michael Adler at AOL, ISIS has a report in draft on the same subject as the article above. Jeffrey previously blogged about suspected neutron initiation experiments in Iran. Mark Fitzpatrick wrote about the diplomacy of Parchin at I translated one of Paul’s previous stories about Iran.


Update | April 14, 9:46 pm. AFP reports that South Korean news channel YTN has described a series of four static engine tests earlier this year for what it calls North Korea’s KN-08 ICBM. Dong-a Ilbo reported on a static engine test late last year. Korean speakers can view the YTN video and read the transcript.

My article on North Korea’s emerging ICBM force is now online at (As always, these are my personal views only.) Go read it first. The bottom line is, we have bigger problems than the upcoming TD-2 launch.

It’s striking that Pyongyang, which presumably cannot afford to build a large fleet of intercontinental missiles, has opted to pursue the ICBM course in the face of the American missile defense deployment in Alaska and California (the Ground-based Midcourse Defense, or GMD). That decision implies some real confidence in North Korea’s countermeasure technology.

Creating effective countermeasures is not necessarily trivial; then again, it’s probably much less of a challenge than building the main components of a working ICBM in the first place. Just how much help the North Koreans received in this area in the 1990s from scientists and engineers at Russia’s Makeyev Design Bureau – the source of R-27 technology – remains unknown. However, the 2010 BMDR Report reported that “proliferators” were deploying countermeasures, and treated “the transfer of advanced capabilities” from other countries as a serious and ongoing problem.

One possible response to the appearance of the new North Korean ICBM, whenever it is finally deemed operational, will be to leave current missile defense deployments unchanged, on the grounds that they anticipated the new development. This stance would be consistent with the claims of two administrations that the GMD system is capable of defending America against the emerging threat.

Another approach – one urged by Rep. Michael Turner in recent HASC hearings – will be to add more interceptors. But if existing interceptors can’t beat the countermeasures, adding more units won’t help. Only if the North Koreans were try to overcome missile defense through sheer numbers of weapons, not though countermeasures, would there be grounds for a numerical strategy.

Against a limited but relatively sophisticated threat, quality counts much more than quantity. It’s risky to put too much faith in sheer numbers.


Now hear this.

If you haven’t already discovered Restricted Data, Alex Wellerstein’s steadily more remarkable blog on the history of (secrecy in) the nuclear age,* then you’re late to the party.

Sorry — nothing terribly clever to say at the moment. I’ll resist the temptation to highlight one or two items, as it would take me all evening to choose. Just go and read.

That is all.

* Mostly in America.

NB. The image above comes from one of Alex’s other websites.