Metallurgist Siegfried S. Hecker is probably the leading US expert on the chemical and physical capabilities of plutonium. He is a former director of Los Alamos National Laboratory (1986–97) and now codirector of Stanford University's Center for International Security and Cooperation. Hecker's expertise has been widely sought both within and outside the US government.
Last October, Hecker was privately invited by the North Korean government to view a new uranium enrichment plant. Shortly after his trip, Physics Today's Paul Guinnessy asked Hecker about his findings, which he published in a recent report.
PT: Why were you invited to visit these facilities?
HECKER: It was the groundwork we have laid over the last seven years that allowed us to come back this time. So the real story is why was I there the first time, which was back in January 2004.
My colleague, John Lewis from Stanford University, had been having an ongoing track II dialog with the North Koreans since 1986. And in 2003 the situation was indeed very grim, in that North Korea had had some altercations with the US in 2002, and had walked away from the nuclear nonproliferation treaty (NPT) and said they were reprocessing plutonium. They told John that they were going to take him to the Yongbyon nuclear facility.
John called me up—I was still at Los Alamos—and said, "Look, I would like to have a nuclear guy along," so I went along.
On this trip they actually ended up showing me their plutonium—not only showing me, but actually allowing me to hold it in a glass jar, in order for me to try to determine whether it truly was plutonium or not. So this trip goes all the way back to the 2004 trip and what I did at that time. I came back out and reported the situation accurately and honestly as to what I saw, and what my assessment was, and so I've been back to North Korea each year since then. So, in essence, we have a standing invitation to go back each time we visit.
In 2010 I actually asked on several occasions to go, and I was told, "We aren't ready yet." Then, in late August, they actually said it might be a good time for me to come in late October, early November.
I told them that since North Korea had now declared [in 2009] that they were going to build a light water reactor and do their own uranium enrichment, I'd like to see those facilities, and they showed them to me.
So that's a very long answer. But in the end, they trusted us to tell the story honestly and then they are willing to take their chance with whatever assessment we make. And that's the way it's worked out for each of the several visits we've made. I've been to Yongbyon, the nuclear complex, on four of these visits.
PT: What exactly is a track II dialog?
HECKER: It means nongovernment, nonofficial, so in other words, you get people who are from universities, nongovernment organizations (NGOs), who manage to keep a dialog going during difficult times, when governments are not able to talk to each other, for whatever reason.
In the North Korea case, the US has no diplomatic relations with them, so unless special arrangements are made, like the 1994 agreement, or the six-party talks that began in 2003, there are no easy mechanisms for the two governments to talk to each other officially. So track II is an unofficial way of keeping the contact, being able to exchange messages and information. In my case, it adds a scientific component to the track II dialog.
PT: How long does each visit last? Do you just go for a week to one or two locations?
HECKER: So each visit that I have done has lasted exactly the same amount of time because of the limited flights into North Korea. We fly via Beijing on Tuesday morning, and leave Saturday morning. All of my seven visits have been the same way, on the state airline Air Koryo.
We schedule an agenda where we do much more than just the nuclear issues. For the nuclear visit, the Yongbyon complex is 90 km to the north of Pyongyang (the capital) and so that complex we visited on Friday this time.
We drive up early in the morning and drive back late in the afternoon. So the only day we actually saw the facilities that I reported on was Friday, 12 November. The other days we went to various universities—Kim Il Sung University, for example, where we saw a very impressive e-library with lots of computers, flat-screen monitors, students studying; a foreign-language high school; and a foreign-studies university. We talked to a newspaper bureau and to various other organizations in North Korea to get a better sense of the whole spectrum of issues and not just the North Korean nuclear issue.
PT: This ties neatly into my next question. How much interaction with the science community do you have on your trips to North Korea?
HECKER: We've had substantial interactions with the schools and universities, with the ministry of education, also to some extent, with the economy ministry, and particularly with one of the universities associated with economics.
This time we went to this incredibly modern apple farm; in the past we have been to various co-ops outside the city of Sariwon. We've had some interactions with the North Korean Academy of Sciences, with the North Korean agricultural sciences, and my colleagues—John Lewis and Stanford epidemiologist Sharon Perry—have actually been extremely successful in working a joint project on tuberculosis with the North Koreans.
Perry has worked with some NGOs to build a TB reference lab in one of the TB hospitals in North Korea. So these track II dialogs have been very expansive, but my central focus has always been the scientific aspects of dialog, in particular the nuclear issue.
PT: How do these dialogs continue when you're not in North Korea? Is it via letters or e-mail? What type of links can you have with the North Korean science community outside of physically being there?
HECKER: So there's only one communications funnel into North Korea: The UN [United Nations] mission in New York, which handles all of the communications with Pyongyang. So, for example, if we request a visit, the trip and its schedule is done through the UN mission. Once we get onto North Korean soil, then we have the ministry of foreign affairs that takes care of us. At which point we then rework the agenda of the trip. There is no direct dialog between North Korea and us without first going through this UN mission in New York.
PT: The main news out of your last trip was this enrichment facility. What's the attraction for North Korea in developing and building such a facility?
HECKER: I'm just writing a couple more pieces that go into more detail on the why and how. My previous assessment of the enrichment program (published in Daedalus, January 2010) is that I believed that they have had such a program for a long time, several decades, but I thought that its current status was still at an R&D level.
That's why I was so surprised when I saw these high bay areas with 2000 centrifuges—so I was wrong. But the assessment that they have had enrichment for several decades is correct.
My reasoning is that because they did not have their own light water reactors [which would require enriched uranium]—and the reactors that they have, which are gas-graphite moderated reactors, require only natural uranium fuel—you don't need enrichment, which is one of the reasons why they chose to use that [gas-graphite] technology.
So if they have been doing enrichment for several decades, it was primarily to give them the second door, the alternative path to the bomb.
Now this facility they actually showed me, I believe that this facility most likely will be dedicated to doing low-enriched uranium for this light water reactor, which they are now building.
They have had an interest in light water reactors since 1985. But they believed that they were not able to build a modern LWR by themselves, so they first tried to get one from the Soviets in 1985. Then they tried to get two of them from the Americans through the 1994 agreed framework, and then in this so-called September 19, 2005, agreement with the six-party talks, they again said they would like to have an LWR.
So what they actually told us, and what you can read in the opening statement in my report, is, "Look, we tried with you, we couldn't get anywhere, and so now we have to do it ourselves."
Again, the long answer is, if they are going to build their own LWR, they need to have their own enrichment. So now they have an excuse for saying that "we have to have enrichment." But their prior interest, in my opinion, must have been motivated mostly for this second path to the bomb.
Even if this building at Yongbyon is dedicated to low-enriched uranium, of course one at least has to keep open the possibility that they have another facility like this which could be dedicated to highly enriched uranium.
PT: One of the things that surprised me was the choice of location for this facility: It seemed like a pretty open spot to build a facility of this type. Do you have any idea why that particular spot was picked to build it?
HECKER: That's quite a puzzle, and that's actually what makes me think that they are going to do low-enriched uranium.
It's my assessment that they have to have had this type of facility operating somewhere else before they moved it this year, because you just don't get 2000 centrifuges—you don't build them overnight, you don't get them operating overnight—so they had them operating someplace else. So if all they are going to do is make highly enriched uranium, why not just keep them there? Wherever they had them?
Instead, they moved them out into the open and chose to show them to me, although I did ask to see them. So they specifically wanted to make this statement: "Look, don't underestimate us. We know how to do uranium enrichment, and here, come and take a look at it. You can see that we did it." So again, that's a good cover for it. They need it for an LWR.
None of us really fully understand how they think and how they lay it out, but to me, it all seems very carefully planned and laid out on their part, including this issue of showing it to me.
PT: So what's your impression of the quality of the facility? I've read in your reports that you thought the control room looked highly advanced. The materials you need to build a facility like this are fairly specialized. Were they developed in-house in North Korea, or were they based on, say, the Pakistani designs?
HECKER: Again, we don't know the answer to most of those questions. As far as the control room and those capabilities, the computers, the flat-panel monitors, and so forth, none of those things are on the export control list, so it's not a surprise they have them. I was just surprised because I hadn't seen anything else that was that modern in that facility.
As far as the centrifuges themselves, again we're not certain. But our best estimate is that we still don't think they have the ability to make their own high-strength steel and high-strength aluminum alloys, so they must have procured that from somewhere else.
But, of course, if you look back over their procurement history, there are many cases where the North Koreans were either suspected or we know that they had procured some of these materials.
The North Koreans have had a very active procurement network for many years, so my own view is that most likely they made procurements for the last 10–15 years or so, and they would then put it all together.
Most likely, they put it together themselves domestically, but they were able to get the components (ring magnets, bearings, vacuum valves, and so forth) in the international market. And these components and materials are on the export control list, but it looks likely they were able to work around the export control restrictions.
This is as much as I want to lay out at this point until I really have more chance to go through, analyze, and think this through. What you're getting now is sort of my top-of-the-head reaction to what I saw, and trying to interpret, how were they able to do this? I wouldn't call this a deep scientific analysis.
In fact, one of the reasons for getting this story out there this quickly is for other people who have been analyzing North Korea for a long time, to now work what I saw on the ground, to see if we can come up with a better analysis of what actually happened.
PT: So how much feedback have you had?
HECKER: I've heard nothing directly back from the North Koreans. However, if you look at the pronouncements of the official North Korean news agency, KCNA, two days after all the flurry of the news of my report, KCNA went ahead and essentially stated what I stated in my report: They are enriching uranium, that it's for peaceful purposes, and they have several thousand centrifuges, in a modern facility. So it's quite remarkable that the North Koreans said that. So one has to look at the timing; they waited to just right after my report, and then they came in and said, "That's what we have."
