North Korea Tested an H-Bomb?

Jeffrey Lewis 0:02

I think that actually means kisses Kim Jong-un's ample posterior. You are listening to the Arms Control Wonk podcast, the leading podcast on arms control, nonproliferation, and disarmament. I'm Jeffrey Lewis, the founding publisher of the Arms Control Wonk blog, and a scholar at the Middlebury Institute of International Studies at Monterey.

Aaron Stein 0:25

And I'm Aaron Stein. I'm a contributor to the Arms Control Wonk blog, and I'm also a senior fellow at the Atlantic Council's Refugee Career Center for the Middle East.

Jeffrey 0:31

You're back, Aaron.

Aaron 0:33

I am back. I think it's been years since we've spoken.

Jeffrey 0:35

Our long national nightmare is over. You're back.

Aaron 0:39

I know. I may be a little bit rusty after not podcasting for so long, but I'm really excited to be back.

Jeffrey 0:44

Ah, we missed you and you came just in time for another nightmare.

Aaron 0:48

Yeah, I think the listeners need to know that we actually had made this, we made the schedule to hold this podcast before the events of last night.

Jeffrey 0:56

Yeah, before the North Koreans conducted a nuclear test. I was sitting at the Cypress Inn owned by Doris Day having a cocktail at the bar. My wife had gone home to relieve the babysitter and I was paying the bill and was going to follow home in my car just a few minutes later. And Twitter blew up.

Aaron 1:19

It did. I first saw it from you and a few of the North Korean hens I follow on Twitter. A little bit of back and forth about was it a test or not based upon some of the seismic data that was coming out.

Jeffrey 1:30

Well, right. So it's clearly a test now. But when the US Geological Survey initially posted its data – The location they gave is close to the test site but still like seven kilometers, seven, eight kilometers away, which is close but not so close that it would be a crazy coincidence. And they listed the depth as 10 kilometers, which is way too deep for a nuclear test.

But fortunately, Alex Kinnard, one of our students – Sent me the Chinese seismic data, which actually I scrape and I have an alert set up before, but it just hadn't done it yet. The Chinese data, though, showed that the event was within two kilometers of the test site and was at zero depth. And, you know, it was on the hour.

Aaron 2:23

Right. So it sort of pointed more towards the likely depth and location of the North Korean nuclear test site, thus raising even more suspicions that it actually was a test.

Jeffrey 2:34

Right. And then the North Koreans cleared it all up. Right. They just made that announcement on television. Right. We have detonated an H-bomb. Okay. That's great. Nice for you. So it was not totally unexpected.

Aaron 2:49

No, no. I mean this is – I was about to like – this is something you've been following. I mean even in my sort of self-imposed exile on paternity leave, I was seeing you pop up with a couple pieces from open source about your monitoring of the test site and stuff like that.

Jeffrey 3:04

Yeah. So we got – for the first time, you can now get 30-centimeter imagery and we got some 30-centimeter imagery in the spring of the test site and you could just see – Things at the test site we'd never seen before. So you could see the entrance to the original so-called North Portal, the original test tunnel. You could see it so clearly.

But what we could also see Were new buildings near the tunnel, but also near the kind of accessing a different mountain, and logs, an enormous number of logs laid out like they were going to be used to shore up a tunnel. And then – so we were really interested in that. And then we got some not quite as good imagery in the fall that showed the logs were gone, i.e.

They'd been put in a tunnel, and there was a big spoil pile. So – Yeah, it looked like the North Koreans digging a new tunnel. I don't know if that's the tunnel they used or not. I'm kind of suspicious. We'll have to really see when the seismologists get a really precise location. But I do think that there was just all this activity at the test site and the things the North Koreans were saying about building thermonuclear weapons definitely perked up my ears.

I'm glad they said it, by the way, because I've been the crank for the past three, four years who are like, no, no, I think they wanted to do that.

Aaron 4:35

No, I mean, that was where I was going with this. The articles that you've been writing about this, I think the last tests were in 2006, 2009, and 2013, just off the top of my head. Gosh, you have an excellent memory, Aaron. I may have studied up before this. And I think in the last one... The last two, the 2009 and 2013, were more successful than the first tests.

I think you were the one that was putting out there that this may be them looking towards developing a first-stage primary for a thermonuclear weapon, correct?

Jeffrey 5:06

Yeah. It's a little bit complicated, and we can talk about what we think they did this time. But I just – to say it really simply, regardless of what they end up doing, I think we have this kind of idea that they're just going to test the same simple fission device over and over again. And I don't know why we have that idea.

I mean I guess it matches our kind of pat the North Koreans on the head like, oh, isn't that cute? You tried to blow up a nuclear bomb. But they don't feel like that. You know, so it always struck me, every nuclear program has looked at moving past simple fission devices and doing more exotic things, whether it's boosting the primary or developing thermonuclear weapons.

You know, even the South Africans were going to boost their gun type devices. So when the North Korean started making comments about H bombs a couple of years ago I took them seriously. And I have to say, my experience is colored by the fact that I studied the Chinese. And the Chinese, from the get-go, like in the 50s, they're like, we're going to build thermonuclear weapons.

And everyone kind of laughed at them. And it's like, no, no, we're serious.

Aaron 6:23

Back up for some of the listeners who may not quite know what all these terms are. Thermonuclear and boosted. Right.

Jeffrey 6:31

Yeah, so... You know, there is a – there's the classical thermonuclear weapon, which is that you use a fission device, a simple kind of what you would think of as an A-bomb. You use the radiation from that to implode a secondary device of thermonuclear material. And that can be huge, right? I mean, you can get – Know megatons of yield out of something like that. Theoretically, there is no sort of upper words limits, just how big you want to make the thing. Yeah, yeah. Edward Teller had this, this life-ending bomb called Backyard, because it could kill everybody on Earth. And you know, you, but it would be too big to move. But that was fine. Yeah, it's fine. You just have to put it in your backyard. Exactly right..

But in terms of practical deliverable weapons, you're looking at Megaton or three. The Chinese have one that's five. Yeah. But there are other things you can do. So for example, there's a simpler intermediate step that everyone – I shouldn't say everyone, but many countries try called a layer cake where you just blanket the device in a fusion fuel.

And it's not as big, but it still gives you some extra yield. And then there's boosting, which is using deuterium-tritium gas to make your explosion more efficient. And those kind of all fall, I think, in the thermonuclear world.

Aaron 8:01

Right. I mean, right. But it's not exactly. So it becomes an issue of semantics. Right. You know, and so I think that's what you've been going on before a little bit about in the previous test, that if you take them seriously, that they're moving towards trying to develop the next stage in the developmental pattern and that this isn't just the same device over and over again, but rather the let's say the start of a quote unquote program.

Jeffrey 8:25

Right, and I think one of the earliest hints that I had about that was this long-running dispute I have with some of my colleagues, who I like. When I say dispute, it's not like Jets and Sharks. I think – and it will be very interesting to see where this test was conducted. But the fact that the same mountain had two different tests in it in 2009 and 2013, I think the North Koreans are building test complexes under each of these mountains so that they can do not just one or two more tests.

They're giving themselves the capacity to do a large number of tests at this site before they have to move. And that to me suggests – it's not just – It's not just a demonstration. The way the South Africans thought about nuclear weapons is that they have a really simple bomb and that they knew it was going to work and they were going to produce a small number.

And if they ever tested, it was going to be for a demonstration. But I actually think the North Koreans have the more traditional view, which is this is an important technology. It's a technology you need to acquire. You need to do a series of tests and it needs to build to something. So when I saw them doing all of the tunneling at the North Korean test site – When I saw them doing all of the tunneling at the North Korean test site, I figured that they were – they have a test program in mind.

Aaron 9:51

Right, which – It's how you conceptualize nuclear weapons, and I think this is an important way to think about it. The explosion should be viewed as a way for scientists to capture data if you want to get more and more precision out of your devices, in order to be able to use them, or anything of just dumping out of the back of an airplane.

Jeffrey 10:13

Yeah, I think that's right. I think that the North Koreans – well, I think for them – They have a variant of the same problem the Chinese had, which is if you ask how their deterrence is going to function, part of it is having the weapons, but part of it is having a kind of respect. And so to the extent that we kind of laugh at them and pat them on the head and we assume that, you know, like, well, when things really come to it, they probably won't work.

Right. But I think for the North Koreans and the Chinese felt this way in the 60s, it's really important for them to demonstrate that, no, they really can do this, that this isn't a joke. It's not a Potemkin capability, that it's really something that we are obligated to take seriously.

Aaron 11:01

Well, just to pick up on that, I think the method that they're testing, too, points in that direction as well. Yeah. They go to great lengths to try and hide their radionuclide signature, you know, for lack of a better term or right. I mean, you know, right. I mean, they're not trying to like demonstrate to the world exactly what the bomb is made of is whether it's uranium or plutonium.

And most of the things that we get out of it are seismic because of the way in which they construct their tunnels.

Jeffrey 11:30

Well, so this is a, this is a, this is a big question that I've had for a while that I've wondered about. Which is, why do they test underground? Testing underground imposes limitations. It's harder to instrument. The Chinese tested atmospherically for a very long time because they found testing underground was just too difficult. To a first approximation, since you have to bury things, it can limit the yields that you can test at.

I mean, if you're really crazy, like we tested a five-megaton device underground in Alaska. So it doesn't necessarily have to be a limit. But for most countries, it functionally serves as a kind of limit for the sort of things you can do. And I think it's that they're really – Leery of angering the Chinese. I think the Chinese populace seems to be very nervous about – every country, people are nervous about radiation.

I think the Chinese government really doesn't want just to deal with the PR problem of North Korean radiation, even if it's relatively harmless, falling in China. Trevor Burrus, Jr.: Right. That's a good point. So I think they try to contain things. It's one reason is we should probably talk about what we think they tested. Although I've kind of hinted I think it's probably boosting.

But the article I was writing when this test happened and made irrelevant was talking about the limits on testing at the North Korean test site. Oh, interesting. Yeah, that you can't really do more than 100 kilotons or two Given the overburdens that are available. Right.

Aaron 13:25

So you want to talk about what we think the thing was? Yeah, no, let's just go into it. We've hinted at it a little bit, but yeah, what do you think it was?

Jeffrey 13:32

Well, so the only data we have right now is yield. So we have the size of the body wave, and the Chinese estimate is very different from the American estimate. So the Chinese estimate is 4.9, the American estimate is 5.1. That's a big difference. That's two-tenths of a unit, which can lead to a pretty big difference. And the other problem we have is it's hard to know what – Equation to use for the North Korean test site.

There's a whole debate about what the best equation is, and some people have tried to calibrate the site using some chemical explosions nearby. It's really hard to know. But, you know, it looks like it's sort of on the same order of magnitude as the last test. Right. Which was? Which was sort of 10 kilotons-ish. Now, the problem is if they're really overburied, they might be bigger and just look a little bit smaller.

But, you know, it's certainly – Certainly several kilotons, and it might be a few tens of kilotons at the max. But it's going to be kind of in that range. The problem is that's a really big range.

Aaron 14:40

Right. I think the thing to put in perspective is how much it differs from the 2006 test in terms of – It's bigger than six.

Jeffrey 14:47

Right. It's a lot bigger than six. Six was clearly unsuccessful. Right.

Aaron 14:52

My point was just to make the program thing. They're calibrating their testing weapons, just setting the same device off over and over again.

Jeffrey 15:01

So here's my best guess about the series of tests. So 2006 was very small and was clearly unsuccessful. I think they were trying to test a compact, deliverable device on their first go. And people will tell you that if you try to do that, you're likely to fail. And I think that's why they failed. I think 2009, the intelligence community has called it apparently more successful.

It was a little bit bigger. I think it probably was mostly successful and was a little bit bigger. 2013 was bigger and I think maybe might have used uranium.

Aaron 15:40

Why? How can you tell the difference? You can't.

Jeffrey 15:43

I mean you can't not – I mean you could if you had the debris. I'm just guessing that that would be what they would do. And they sort of announced that it was miniaturized. It could have been plutonium again and they just finally were happy with it. And so that leaves this test. This test is about the same size as 2013.

It might be a little bigger. It might be a little smaller. We'll have to see what the actual data comes in looking like. Yeah. So it's clearly – it's not big enough to be a two-stage thermonuclear weapon. It's just not that big. And it's possible that it failed, although I tend to lean against that because they did it – if they did it at the test site, then they weren't expecting something that big because it would have blown out of the mountain.

So I'm guessing that they were expecting something – In the range they got, or maybe a little bit bigger. If that's right, and it's not a failed thermonuclear device, I think the most likely explanation is that it's a boosted fission device. So they've taken their plutonium or maybe their HEU device, they've managed to reduce the size and In reducing the size of it and losing yield, they've made up for that with design innovations, one of which would be using boost gas to get a more efficient explosion.

And I think there are hints of that in their statement, right? Because they released this statement where they really talk about this like it's a deliverable device. And, and it seems to me that one way you could do that would be boosting. So that's, that's what I'm leaning toward. But you know, we're not going to know unless debris leaks out.

Yeah.

Aaron 17:31

It has not in every test.

Jeffrey 17:33

No, not the 2009. It leaked for six and 13, but not nine. Right.

Aaron 17:43

So they made this – could it be that they're testing the – I mean as we've talked about earlier, it's not really that they're lying that this is a thermonuclear device. But this is sort of one component of a thermonuclear device that in the future they intend to build upon?

Jeffrey 18:03

Well, so a boosted primary – I mean a boosted fission device will serve as a primary for a thermonuclear weapon. So, reducing the size of the simple fission device, or in their case, I guess they tried a compact fission device, something that was probably 500 kilograms or something. If you can get that down further, then you've got more room left over on a missile for a secondary device.

So, you know, boosting – you could argue that boosting is thermonuclear in terms of the reaction. And as a consequence of that, you could take credit for it. But I think you can also see boosting as a step toward reducing the size and just generally doing a fancier job of building the primaries that will drive a secondary reaction.

As you can tell, I don't think they're going to stop here. I don't think they're going to say, okay, we're good.

Aaron 19:10

No, why would they stop? There's no reason for them to stop because you have the concurrent development on the other side of more capable ballistic missiles, both submarine launch they're testing right now and some of their ICBMs that are in development.

Jeffrey 19:27

By the way, they have said that they will not suspend nuclear development nor – They phrase it in this terrible Korean-English way, but there can neither be suspended nuclear development nor nuclear dismantlement on the part of the DPRK, unless the US. It says rolls back its vicious hostile policy, but I think that actually means kisses Kim Jong-un's ample posterior.

Aaron 19:56

Yeah. I don't know. So what does it mean? I mean what are the policy implications of all this? I mean because I think they've been very active on the missile side as well. I think you have a piece up on – with a few other co-authors who I can't remember off the top of my head up on 38 North about I think what you saw from their military parade.

Jeffrey 20:18

Right. Well, so we're also trying to model that their missile. They have this ICBM and they paraded a – Newer, fancier, pantsier-looking version of it. And we were trying to model it just to figure out what's going on with it.

Aaron 20:38

And that's also my point, is that you just have this... It just looks like a program, and it's just something that I keep saying over and over again, because I think program shows off that they aren't stopping, and that this is something of a well-conceived thing to marry a warhead to a missile, to actually have a quote-unquote deterrent, however it is that they define deterrent.

I don't quite know how they define deterrent.

Jeffrey 21:03

Yeah, I think... The original view of their program – and by the way, I don't think this view was wrong. I'm not denigrating it. I just think we've moved on. But I think when North Korea – when these things were aspirational, I think the idea was they would trade away capabilities that they had not yet built in exchange for better relations.

I don't think that was crazy at all. I think that that made a lot of sense, because North Koreans were giving up something they didn't have in order to get a goodie. But that process, I think, has basically failed, and neither the U.S. nor the North Koreans have much faith in it. So the North Koreans have then said, okay, fine, if you're not going to improve relations, then we're going to do this other stuff.

And I think over time— They've really begun to lean on that other stuff as like their claim to fame. You know, that's what's special. So maybe a year ago or so, no, it's going to be longer than that, two, three years ago, there was this movie called The Country I Saw, which is a North Korean propaganda film.

It's like a five or six part movie. It's really long. We had some poor researchers that watch it. We were terrified, you know, that she was going to like, like, Like, you know, go over or something. I mean, what happens if you binge watch six hours of North Korean propaganda, right? But the whole subtext of that movie is that like, what makes North Korea special is its missile and nuclear program.

You know, that that's the sign that the Kim family are good at leading the country. And so it just, it's always seemed to me that It's always seemed to me that it's harder to get people to give up something they have rather than to give up something that they might have. And once they have it, part of the reason it becomes so hard to give up is it becomes part of their story of who they are.

So you're not just asking them to give up this capability. You're asking them to change the story they tell their people about why they're a well-run country, and I just think it's going to be really hard. So yeah, developing a thermonuclear weapon down the line, that's a pretty good PR day for them, and I think they want that.

Aaron 23:36

Yeah. No, I mean it's a big bang to bring in the new year. Right, right.

Jeffrey 23:42

Happy New Year. Happy Spring Festival, right?

Aaron 23:46

Yeah. I mean, as we just turn to wrap up here, I mean, what do you think the policy implications should be for the U.S.? I mean, in a nutshell, anything we can do about this? Or as you say, are they just creating facts on the ground? I mean, and sort of the aspirational things that you could trade away, capabilities for better relations with the United States or more – Let's say coherent relations with the United States is a thing in the past of 10 years ago.

And now we're just dealing with a whole different entity that's, that's moving, that's moving forward. And there's no really end in sight.

Jeffrey 24:16

Yeah. I, I think, you know, the core question that we always have to deal with, I think there are, there are two So I guess they both can't be the core question. But there's a kind of core question about the nuclear piece, but then there is this core question about the relationship. And the core question about the nuclear piece is, do we recognize North Korea as a nuclear power, right?

I mean, there's this kind of discussion about – like we know they have them, but are we willing – To engage with them on the basis that they are either going to retain some of these capabilities or all of them. It's really hard, I think, for the US, and I'm one of the people who's argued we shouldn't give up that idea.

It's very hard The more their capabilities advance to continue to say there's no prospect for improving relations unless you return to a state of denuclearization. And so it just becomes trickier to manage. And I think the real reason that that's hard is in this big – there's this fundamental relationship question, which is – Why would the North Koreans have ever considered trading these things away in the first place?

It's because I think because they want legitimacy. They want to be seen as a normal state. I think that's just really hard for us. We find them horrible, and we don't want to see them as a normal state. And the reason that nuclear weapons kind of factor into this, which to me is really interesting, is part of our idea that they're not a normal state is that they're this kind of living fossil, that they're this abnormality that has inexplicably survived.

And so the idea of this bizarre, backward state building nuclear weapons just seems bizarre to us. It's just wrong. And so it's just hard to accept. But like that's exactly why they're building nuclear weapons, right? Because we see them that way and they don't like it. And so building nuclear weapons and testing missiles is their way of trying to force us to see them as a normal state that maybe we don't like but that we have to deal with and that we have to respect and that we have to take seriously.

Yeah. And so, you know, I think we're kind of like trapped in this cycle because the more they do that stuff, the more abhorrent and abnormal they seem to us. And so the more we're just like, ah, we don't know what to do with you, get away. And so the more they want to do that stuff.

Aaron 27:06

But you see a growing strain of people. I mean, it's just not the Chinese deal with this. Like, we're done. There's nothing we can do any longer.

Jeffrey 27:12

Yeah. So, you know... I think we have some really tough questions to ask. We have this rhetorical emphasis on denuclearization that we have to keep, but how do you make that rhetorical emphasis sound not ridiculous given the progress that they're making? Right? That's a challenge. Because if you just keep repeating the denuclearization formula over and over again, I think people will start rolling their eyes.

Like, oh, really? What are you going to do? Send them a sternly worded letter?

Aaron 27:41

And sanctions.

Jeffrey 27:42

Yeah. So there's got to be like a story here about how we get from A to B. But I think we have to reach some closure on – This big question about whether we can live with them. Sadly, I think we're stuck in this really unproductive cycle where the status quo stinks, but in a weird way, it serves our interest.

Because on the one hand, we don't want to have to topple that government and deal with all of the chaos. But on the other hand, we don't want to admit That we're willing to consign everyone in North Korea to living under this horrible government. The best thing or the satisfactory bureaucratic answer is to say one thing and do another.

I understand why we do that, but on the other hand, I think it inhibits our ability To make hard choices about whether we want to manage the security threat with them through just deterrence and sanctions and pressure and then deal with all of the bad stuff that they're going to do in response to that, or whether we want to try to manage that problem by tactically trying to cut deals with them, which frankly looks a lot like bribery.

And I kind of – I have a bunch of friends who disagree on this, and I think all of us can see it each way, but kind of nobody wants to choose.

Aaron 29:17

No, I mean, it's a policy conundrum – I sort of lean towards the let's live with them type thing because they've moved so far down the road and that cart has sailed on denuclearization. But I could be a pessimist. But you have the added complications of our security agreements inside the region, South Korea, Japan and all these things and how that affects their security structures, how they then turn to us for help and then we are forced to deal with it.

We can't just simply consign it off to the Chinese or just live with it. Right. Yeah.

Jeffrey 29:46

So this is not – we're not ending on a happy note like usual. Yeah, I guess that's true. Well, let's see. Oh, happy note. I know what the happy note – no, it's a selfish happy note.

Aaron 29:58

I told you so. What do you mean you told me so?

Jeffrey 30:00

No, I mean I've been the crank running around for a couple of years saying like, no, they really want to – They really want to do more than just build a small arsenal of simple, efficient devices. Even if they haven't necessarily succeeded in doing much more, we'll have to see whether this is just balderdash or whether they really were boosting.

I do think that we're now at the point where their rhetoric has changed in a way where people are starting to take seriously the idea that maybe the North Koreans have ambitions that seem a little outsized for our perception of them.

Aaron 30:36

So that means we're going to have to hold more podcasts in the future when they hold more tests?

Jeffrey 30:42

Yeah, especially if this turns out to have been in the North Mountain and they've got all these tunnels just sitting there waiting. Are you foreshadowing an OSINT piece? I don't know. No, not necessarily right now. We're just going to wait for them to come back with the seismic data and get a really nice, really precise location, and then we'll try to sort through what all this means.

Aaron 31:03

Off and running.

Jeffrey 31:05

Hey, Aaron. Thanks for coming back.

Aaron 31:08

I'm very happy to be back.