Fear in a Handful of Dust

Published Jun 20, 2023

Exciting new research allows UCS scientists to gain insight into North Korea’s shadowy nuclear weapons program. Jess talks with UCS researchers Dr. Sulgi Park and Dr. Laura Grego about this work, and the current state of worldwide nuclear affairs.


“When I heard about The Third World War, I stuck a stone in my backpack, a stolen star.

I tried to unplug My electric sheep. I stroked pink lipstick, I paid to cheat.

I baked in a bunker buried in my dress as hot birds flew bombs north by northwest.”

That was from poet Eileen Murphy’s “Apres Moi, Le Deluge” or “After Me, Annihilation.” I first heard this poem performed about 20 years ago, in a theater class I took during my undergraduate years at Smith College. The poem made a strong impression on me…enough that any time I hear reference to nuclear war, I imagine hot birds flying bombs north by northwest.

Now, as a child of the 80s I remember when the Berlin Wall came down. With parents in the FBI, I heard stories of espionage and foreign counterintelligence. When former FBI agent Robert Hanssen was convicted of spying for Soviet Russia, my parents told me he was in their carpool when they were based at FBI Headquarters…but they didn’t ride to work together all that frequently.

Like most people, I find the idea of nuclear war alarming…and remote. It seems like something that belongs to another lifetime, another history. The horrors of the United States bombings of Hiroshima and Nagasaki are largely viewed through the black and white lenses of photographers nearly 80 years ago. They’re not something humanity could ever witness again…or are they?

Our planet today still plays host to thousands of nuclear weapons. The treaties and de-armament agreements that have curbed the proliferation of these weapons are slowly dissolving, with the greed of dictators and autocrats fueling the fire and the complacency of a public exhausted by toxic politics, the ongoing collective trauma of a years-long pandemic, and the creeping environmental catastrophes wrought by human-fueled climate change giving oxygen to the flames.

That’s not to say that a nuclear arms disaster is inevitable. On the contrary, there are thousands of dedicated scientists, analysts, and diplomats working diligently to quantify, illuminate, and protect against the existential threat of nuclear weapons. Novel investigation like the work done by Dr. Sulgi Park of the Union of Concerned Scientists uses our understanding of the Korean Peninsula’s regional geology to help us understand the limits of North Korea’s insular nuclear weapons program.

We have more knowledge, technology, and insight than ever before into the hazards of nuclear weapons. We know that the greatest threats are not posed by rogue nations like North Korea, but by the possibility of an accident or miscommunication by the United States or Russia, the nations with far and away the largest numbers of nuclear weapons.

We need to use all of our available scientific resources to make good nuclear weapons policy. I’m thrilled to speak to two scientists who are using their training to drive meaningful change on the world’s nuclear weapons policies. Never again should hot birds fly bombs north by northwest. I’m your host Jess Phoenix, and this…is science.

Jess: I am now here with Dr. Sulgiye Park and Dr. Laura Grego, and I'd like to start our conversation today with Sulgiye. I found your work really, really interesting. When I first heard about what you do, because I'm a geologist, I think, I totally nerded out on this. Now, you can embellish this if you'd like, of course. But from my understanding, your work looks at the pathways of uranium in North Korea. So, basically, you study the mining and the milling. And essentially, you're using geology to understand the world's least accessible nation and what it's doing in terms of nuclear capabilities. Is that accurate?

Sulgiye: Yeah, that is accurate. So, North Korea's nuclear activities are ongoing. It's active. They are making nuclear weapons, they're increasing it in terms of its quantity as well as its quality. And there are two major fissile materials that are required for making weapons. There's weapons-grade plutonium, and there's weapons-grade high-enriched uranium. The plutonium does not exist in nature, we have to make it by combusting uranium in the reactors, but uranium does. And given the heavy sanctions against North Korea, we believe that mining and processing its very old indigenous uranium will be the very much first, and might be the most rate-limiting steps in making nuclear weapons. So, we are looking at that from a geological perspective.

Jess: Okay. So, I'm a geologist, but I study volcanoes. It's nothing like studying radioactive materials that are used for building weapons. So, how did you come to focus on North Korea's nuclear capabilities? Because the last thing I ever thought about in geology class was, "Hmm, I'm gonna go study North Korea."

Sulgiye: No, it's true. And vice versa, right? No one talks about hiring a geologist in the field of security. So, I actually stumbled upon this project a few years ago with my former advisor. So, I was still doing mineral physics as part of geology back then. But my formal advisor, who was the director of the CISAC, Center for International Security and Corporations, at Stanford University approached me and said that there are a couple of people in that institution was looking at North Korea's uranium mines from satellite imageries, right? And he asked me, "Do you wanna use geology as a way to complement those analysis?" The first thing I thought was, geology, uranium, it's been done already, right? Everyone looked at that already. There must be tons of articles out there.

So, I started researching that and there were quite a bit of information, but none of them had really good scientific justifications that there were numbers, but there was no consensus. And a lot of these numbers were cited in the form of news media. So, I didn't see, like, really good peer-reviewed geochemical literatures that was talking about uranium resources in North Korea from a geologic lens. And I thought that was interesting, right? And then no consensus, meaning that you get numbers anywhere from like 100 tons of uranium production capacities to 200,000 tons of uranium production capacities. And I got curious, like, where did these numbers come from? Who talked about these numbers? What is the unit for these numbers? And the curiosity pretty much brought me to looking at uranium resources from the geological perspective as a way to complement the security studies.

Jess: Geology can be really boots on the ground, at least historically. And then recently, we started to use satellites more, and and more, remote-sensing technology. So, I know that you can't just walk over to North Korea and say, "Hey, let me study your rocks." So, what do you use to gain insight into the country's nuclear capabilities?

Sulgiye: Right, excellent question, Jess. In modern geologists, they would combine so many different techniques, satellite imagery, geophysical to geochemical tools, right? And then they go in and if they see any potential, what do they do? They start drilling. I wish I could do that in North Korea, but I probably would not survive or make it alive. So, I have to use available geologic data. That means geological maps. So, I started gathering all of the geological maps that I could ever find that pertains information on North Korea. So, I found tons of geological maps published by different institutions across the world, anywhere from the periods of 1920s to 2018. And that was just to make sure that independent geologists came to the same conclusions, right?

And then I look at the primary documents like those from the CIA, those from the International Atomic Energy Agency. None of these really gives me, like, actual hand samples that I wanna look at. So, what I had to do in order to complement those analysis is find places around North Korea that has similar geological settings. So, I went to South Korea, I found the place that has comparable geological settings. I walked in there, I started gathering some of the samples. I looked at the geochemical literature data that exists on those deposits and started making comparisons to infer what kind of deposits, what kind of characteristics uranium resources North Korea could have. So, that's the only way I could go about this project. One day, one day I will try to get samples from North Korea to do my own analysis.

Jess: That's pretty incredible. So, you did get to do a little bit of boots-on-the-ground work, but ou had to infer a lot. And, I mean, we do that as geologists all the time. I mean, if we see a layer that is cut off by erosion, we have to say, "Well, we infer that it would continue." And so, I guess you're just taking that to the next level and then applying it to geopolitics and security,.

So, what are some of the recent developments in North Korea? Because I did read a blog that you wrote on the UCS website not that long ago about some of the more recent things. So, I thought, "Hey, I should ask Sulgiye to tell us what's been going on."

Sulgiye: So, North Korea has a nuclear reactor that they are dedicating to make plutonium. And plutonium is the potent fissile materials that they can use to make the weapons. And they started building this reactor just back in the 1980s. It first went critical, I think, in 1986, if I remember correctly. So, it was operating for 37 years on and off, but it stopped operating in 2018, and re-started operating in 2021. So, that's pretty recent. And over the past couple years, that reactor has been turned on, meaning that they are generating spent fuel. From the spent fuel, they are reprocessing plutonium.

If you get about 5 kilograms plutonium, you make one nuclear weapon. And the capacity they have at that nuclear reactor is about 6 kilograms of plutonium per year. And so, if they operate it per year, they can make approximately one nuclear weapon. And so, they have been doing that since 2021. And then last year alone, during the global pandemic, they tested more than 70. Few months ago, they tested solid fuel ICBM, that's an intercontinent ballistic missiles. And that's a pretty new model form of ICBM that has the capability to reach United States. Accuracy, debatable. But whether or not it can reach us, yeah, it can. So, it's really, really scary if you think about it.

Jess: Based on your research, is North Korea limited in any way in the number or the size of the weapons it creates?

Sulgiye: So, that's a really excellent question and that's actually the bulk of my study that I'm trying to do, Jess, what is the production capacity and capabilities of North Korea? What is the rate-limiting steps? It's still an ongoing research. To me, the biggest rate-limiting steps for North Korea is really the fissile materials that they can produce in order to make the weapons. So, I'm looking at both pads, how much plutonium can they make, and how much high-enriched uranium can they make? And both of these factors actually do depend, again, on uranium, which is why it is critical for us to better constrain or better understand exactly how much uranium they have, and what is the quality of that uranium. Because ideally, theoretically, they should not be able to import any uranium materials. In terms of technology, I think sooner or later, North Korea will get there in terms of making whatever weapons that they wanna make. It's definitely behind more modern countries like United States. But they are diversifying the types of weapons they wanna make, including hypersonic weapons, they're talking about technical nuclear weapons. So, they're clearly diversifying the quantity as well as the quality of it.

Jess: It's just fascinating to me that you know so much about a country that seems so mysterious to the general public. I mean, we hear a lot about North Korea, but I think our understanding, especially in America, is it leaves something to be desired. What drew you to this work, and this work on North Korea particularly? Because it is mysterious to a lot of us.

Sulgiye: Well, first of all, I find the intersection between science and policy to be just fascinating. I feel like more scientists and policymakers need to talk to each other, and we really need to have more conversations than we already do. I'm South Korean. I'm just interested in the Korean Peninsula issues in general. And I think it's important to use evidence-based analyses to do policy work. And I think geology is one of the most versatile tools that one could use in various fields, including security fields to provide evidence-based analysis in times when we don't actually have access to countries like North Korea.

Jess: Yeah, that's music to my ears. I'm a big fan of evidence-based policymaking. And so, then kind of the last question I had for you right now is, do you see an increase in the willingness of scientists to speak out about things that are considered political, like geologists and nuclear weapons? Are you seeing that, that sort of people are more open to that possibility recently?

Sulgiye: I really wish that more geologists would come into play. I do definitely think that it is an important question, Jess, and more and more scientists should try to talk more vocally about the political issues. When somebody first came to me and asked me, "Do you wanna work on nuclear weapons?" I was working in the lab, I was making diamonds in the lab. And nuclear weapons is one of the last things that I wanna think about on a daily basis. But I decided to stick in this field because once I was in it, I realized how important it is for the policymakers to hear science, just science, right? So, I hope that more scientists acknowledge this issue and that they can raise their voices and really jump into the field where they can help make better decisions.

Jess: That's excellent. I think that we need those kind of rallying cries for the scientific community. Because we've been told for a long time, "Oh, science needs to stay out of politics," when in reality, we need more scientific data in the policies that we make.

I wanna turn to Dr. Laura Grego now who is also with UCS's Global Security Program. Would you be able to give us sort of a general overview of the state of global stockpiles of nuclear weapons? Like what is the current state of play? Laura: Sure. Okay. So, we were just talking about North Korea, which is the newest country to acquire nuclear weapons, the newest out of nine. So, at present, there are nine countries, including the United States and Russia, which collectively account for some 90% of all nuclear weapons in existence. And then there's China, France, the United Kingdom, Pakistan and India, and Israel, as well as North Korea. So, there are some like 12,000 nuclear weapons in existence, still threatening our existence of which about 9,400 are in active military stockpiles. So, given that a single nuclear weapon can destroy a major city and kill millions of people, and perhaps dozens or scores can end a functioning society, complacency about still living with nuclear weapons seems pretty misguided to me.

Jess: Your background, I'm gonna go out on a limb and say you're probably not a geologist. So, what is your educational background, and what led you into this field?

Laura: I've been trained as a physicist. I was an experimental astrophysicist, cosmologist. I built instruments, radio receivers, to look at the biggest structures in the universe and try to discern what the cosmological, certain cosmological parameters were, using the universe as a tool and building things in the lab as one of our approaches. So, I loved that work. I really did. And yet, I consistently found myself, I guess, the jokey way I talk about it, I was like hiding my "New York Times" behind my astrophysical journal because I was really compelled by the problems of thereally problems of humans, and really wondering could...I've been trained as a scientist, I really loved science. How could I use my training to address more of these problems? And what kinds of problems does my training allow me to investigate?

And so, I spent a year asking a lot of questions, talking to a lot of people, like, how do people do this? What are the kinds of questions I can move into? And it turned out that the program I'm in now, the global security program, had a fellowship that allowed sort of a soft landing from academia into the policy world, and kind of gave me the tools and the training and a set of problems to start working on. So, the original issues that I was working on were space security issues, space weapons, because at that time, the George W. Bush administration had plans for building...wild plans for space weapons and sort of to dominate the heavens. But it was really clear that a lot of the way people were talking about it was not undergirded by a technical understanding of even how space works. It was really a lot more like "Star Wars" maneuvering in space and pew, pew. It was like, that's not how space works, and you can't really have a policy discussion unless it's bounded by the technical realities. So, that was one of the first things I worked on, was trying to write and educate policymakers and come up with good policies to put some bounds on those questions.

Jess: That's a really interesting career journey. And I love it because it just goes to show that science can take you in almost infinite directions in your life. Back to the nukes, because that is really fascinating, but I gotta ask, so I'm a little familiar with some of these terms, but for anybody listening who might not be, what is the difference between those tactical nuclear weapons that we've heard about, and then strategic nuclear weapons?

Laura: One way you can really think about them, the strategic nuclear weapons are generally larger. They are meant to support this theory of deterrents and mutually-assured destruction. It's meant to threaten the other country, the other actor, so that they don't attack you. So, it's nuclear deterrents. And when you think about tactical nuclear weapons, those are generally smaller and may be described as a battlefield nuclear weapon, meaning something that's meant to be used in war to achieve a military aim rather than threaten overwhelming destruction. It's like, I'm going to use this to achieve some military things. So, it's mostly the way they would be used, but they do tend to be smaller. They would be put on shorter-range missiles or on bombers that can go a shorter distance. But that's essentially the difference.

Jess: That's really helpful… wall nuclear weapons are not created equal. And it seemed, and this is, of course, late '90s thinking, but it seemed like the world was generally in agreement that we needed to reduce the number of nuclear weapons in existence. And the Cold War was supposed to be over, and government leaders wanted to make sure that mutually-assured destruction, that principle that I'll blow you up if you blow me up, that that would go the way of the dodo, and we would not be threatening each other anymore this way. But obviously, I mean, this is what Sulgiye is working on right now, you're working on it, a ton of scientists are globally, and a lot of politicians too. So, from your perspective, why haven't we gotten rid of nuclear weapons?

Laura: I would agree with you that mutually-assured destruction is not a healthy way to organize a society, to organize humanity. We cannot coexist with that indefinitely. So, we absolutely have to find a solution how to get further. So, after the Cold War concluded, after the Berlin Wall fell, and it was no longer sort of two superpowers with enormous arsenals, and at one point, tens of thousands of weapons pointed at each other, we were able to back that off and reduce them to the numbers we talked about earlier today to the United States and Russia now deploy around 1,500 nuclear weapons aimed at each other. And even the small ones, when we talked about tactical nuclear weapons, they're the size of the weapons that were detonated in Hiroshima and Nagasaki. So, they're not mini, they're not small, they're still city-busting weapons generally.

And so, we backed down, but it's nuclear...For some reasons, nuclear weapons appear to confer a sense of power. You'll notice that the P5 of the United Nations, the countries that get to make the ultimate security decisions, are nuclear-armed. So, it confers this power that countries are reluctant to give up.

I mean, we could have ended up with many, many, many nuclear weapons countries, but we haven't. I mean, I think that's a real success that we're only at nine. It could be many more. But countries that have nuclear weapons have...they committed to disarmament. That was part of the deal, and we're supposed to be working towards there. And I think we've been frustrated at the lack of progress. I think other countries have been pretty frustrated that we're just not getting much further. And, in fact, most of the major nuclear weapons countries are spending enormous amounts of money to rebuild their nuclear weapons, make them more modern, make them do different things, make them last for investing in having them for decades to come. So, we're up against a lot.

And so, I do think bringing the voices of scientists to bear who I think really are really able to testify about just what a risk nuclear weapons pose to all of us. We can bring that information in a clearer, scientifically-informed way. We can talk about solutions, about ways that we can work together. We can disarm, we can verify that we've disarmed, we can verify...There are big technical projects such as that mounted by the comprehensive test ban organization, which has seismic sensors and air sensors that can say, "Nope, we are still not having any nuclear tests." There's ways that science can really provide solutions to this. And then, of course, we need the voices of everybody because we are all at risk from these. So, even non-scientists, everyone else should...Their voices really count because we're all experiencing the risks of these things. So, I wish I could say exactly why countries have resisted so much. But I do think that we cannot wait to do better, so.

Jess: Yeah. It's such good wisdom that you just shared there because it's science informed by our shared humanity, and I really appreciate that. From your perspective with having all the education you have in this field, what is the greatest nuclear threat today with the current state of geopolitics? Because I know in the U.S., we like to point the finger at North Korea and go, "Oh, look how scary it is over there." But I seem to understand that the U.S. has way more nuclear weapons than North Korea does, and so does Russia. And to me, it seems like maybe we're looking at the wrong thing.

Laura: We spend a lot of time thinking about North Korea and what is North Korea doing, and we should always be concerned about the proliferation of nuclear weapons. It's always a concern. But you pointed out correctly that the United States and Russia have, by far, the majority of nuclear weapons, and not only possessing nuclear weapons, but have them mounted on delivery systems that are ready to be used basically at a moment's notice. I mean, the U.S. president can call a strike and have this in movement within 15 minutes and start a nuclear war. A president can do this. So, of course, there are laws and there are restrictions, and I don't think our greatest threat is that a country will start deliberately a destructive nuclear war. I think everybody has that basic understanding that nobody would win in that case.

But what I think is really risky, right now we're in...I've heard it called the riskiest time since the Cuban Missile Crisis. And I think that's right because we have the collapse of arms control treaties, which put constraints on the numbers of nuclear weapons and delivery systems that the United States and Russia could field. The New Start treaty is the one in existence, and it is slowly breaking down. And it will expire in 2026 anyway, if we don't renew it or replace it with the next treaty. And a number of other arms control treaties have gone by the wayside because the United States has pulled out, or other reasons. So, we have fewer constraints than we used to.

We have more investment in nuclear weapons, weapons on high alert, and we have the Ukraine War, which threatens to bring nuclear-armed countries in direct conflict with each other, and threatens to have multiple pathways to a crisis getting out of hand, which might lead to an escalation that nobody wants, but that could turn nuclear. So, we wanna be extremely careful about managing those risks. I think to me today, that's the one I worry about the most is some misunderstanding, miscalculation, somebody painting themselves into a corner and seeing the only way they can get out is to escalate. I think those are the things that provide the most nuclear risk today.

Jess: Okay. Yeah. Vaguely terrifying, as we expected. I mean, it is nuclear weapons, so.

Laura: Sorry, Jess.

Jess: Hey, that's all right. We know we're here to talk about the real lighthearted topics, kittens and nuclear warfare. Laura: A day in the life.

Jess: So, I'm gonna ask, and I ask this of all of our guests now, I say we are the Union of Concerned Scientists, and the thing is, you are both scientists at the Union of Concerned Scientists. So, Sulgiye, why are you concerned? Sulgiye: That's right, I'm very concerned. I'm a very concerned scientist working at the Union of Concerned Scientists. Doing the work that I do on a daily basis at the UCS, I'm looking into North Korea, I'm looking at China. I'm concerned because a lot of the politicians and policymakers tend to ignore the important scientific facts when they come to making decisions.

Jess: Very good answer. And I think I share that concern, so no arguments from me. And then, of course, I've gotta ask Laura the same question. Why are you concerned?

Laura: Well, I'm concerned that human beings have a really hard time assessing low-probability, high-consequence events like nuclear war because it is a low probability. We've lasted some decades without nuclear catastrophe, which is wonderful, and we want never for that to happen. But the consequences are so high that I think we have a hard time understanding how to deal with that. So, we have to minimize that risk really carefully and really thoughtfully with a lot of...And none of these questions are easy, they're just...they require a lot of cooperation, a lot of good faith negotiations, and types of things that are in short supply in geopolitics today.

And the other reason I'm concerned is that for the nuclear weapons space, when I was growing up, I'm Gen X and I grew up like all our popular culture touchstones had nuclear armageddon hanging in the fringes, right? That was like a constant sort of setting for us. And the current generation coming up are really cognizant of the risks that climate change pose, but I think are less-acculturated to thinking about nuclear weapons. It wasn't part of them. And I want to make sure that this next generation, who's gonna be handed this really deadly contraption, understands these problems, is ready to step in, is ready to be active about it. So, I think the generational change is something that I think about a lot. So, I would love any younger person listening to this really take this to heart that, I'm sorry we're gonna hand this off to you, but it's a big responsibility. I would love if we solved it before it becomes your problem, but I don't think we will. Jess: Yeah. I mean, that's a great set of concerns from both of you.

And when it is something like what you both are studying...which, thank you both for the work you do because we need awesome badass scientists like yourselves tackling these problems to keep us safe. But when we talk about these things, we need to educate the public that this isn't something from Cold War days. This is now, this is the world we are in at the moment. And I think that the more we can amplify what you study and learn from your work, the better off we will all be. So, I feel actually a lot better. I think I'll sleep better tonight knowing that Sulgiye and Laura at UCS are fighting the good fight here, and are trying to use science to solve problems. So, thank you both for taking the time.

That’s a wrap for today’s show. Big thanks to Rich Hayes, Omari Spears, and Brian Middleton for helping produce this episode, and to Anthony Eyring for our graphics and video production. Also, thank you to you: our wonderful UCS supporters. None of this is possible without you. Until next time, Science Lovers.