This BBC podcast is supported by ads outside the UK. designer, marketer, logistics manager, all while bringing your vision to life. Shopify helps millions of business sell online. Build fast with templates and AI descriptions and photos, inventory and shipping. Sign up for your one euro per month trial and start selling today at shopify.nl. That's shopify.nl. It's time to see what you can accomplish with Shopify by your side. Hello and welcome to BBC Inside Science from the World Service with me, Marnie Chesterton, and, as you'll hear shortly, Victoria Gill. This week we're devoting the whole show to nuclear energy, or rather one of its downsides, the waste. Since the 1950s, countries' power grids have welcomed in the atomic era. Nuclear fission, splitting the atom, usually uranium, produces large amounts of heat, which makes steam, which powers turbines. It's a reliable 24-7 source of electricity that doesn't add to our greenhouse gas problem. There is one small but mighty problem. What to do with the radioactive waste? Over decades, radioactive waste has been stored in pools or other special containers near the site of nuclear plants. It's safe, but it's also a short-term solution, acceptable while we wait for science to think up something better, suitable for keeping radioactive waste out of harm's way for tens or hundreds of thousands of years. Over this episode, we'll be visiting Onkalo in Finland, the first national facility to provide a long-term solution to nuclear waste, burying it deep underground. We'll also be sidestepping into philosophy and art to try and answer the question of how you stop future civilisations from getting curious and digging it up again. But first, let's get to the science of what this waste is and why we produce it in the first place. Victoria Gill spoke to Clare Corkhill, Professor of Mineralogy and Radioactive Waste Management at the University of Bristol in the UK. Really simply, it's the byproducts that are generated from the production of energy inside a nuclear reactor core. But we have to think about it in a little bit more detail to understand exactly what that means. So inside nuclear fuel, which is made of uranium dioxide, uranium is a radioactive element, inside the fuel, the uranium splits and it splits into smaller atoms. And as it does so, it releases a large amount of heat. That heat we use to heat water, to turn into steam, to turn a turbine, to create energy. And that's how nuclear power is produced. But those smaller atoms that uranium is split into are also radioactive. They're unstable and they want to split into even smaller atoms. And every time they split, they release some radioactivity. So inside the uranium nuclear fuel, constantly as it's being burned, we build up more and more radioactive atoms that are creating these little bursts of energy that could be penetrative to human tissue or to biological tissue causing damage. Right. So that waste material, those atoms that are produced when the atoms split inside the reactor core, they're spontaneously releasing energy that can harm us, can get into our bodies and harm us. Yeah, exactly. And that's one of the reasons why we have to think about looking after these materials over a long time scale. So some of those atoms that split, they split very quickly and they have what we call a radioactive half-life. That's the amount of time it takes for them to split and then decay to a stable element. Some of them have radioactive half-lives that are very fast, so on the order of seconds. But some of them have radioactive half-lives that are on the order of hundreds of thousands of years or even millions of years. and that's why we have to really keep an eye on this nuclear material, this radioactive waste, after it's been removed from the reactor because it's going to be hazardous for a very, very long time. So if we're dealing with that waste collectively, we have to come up with a plan for its disposal, for its containment away from human contact, away from the environment for the longest of those half-lives, for the longest time that any of that waste material is going to be harmful. Yeah, that's absolutely right. So what we would like to do is wait at least 10,000 years because that's the amount of time it takes for the radioactivity in the fuel to decay to the same level of radioactivity that was originally in the uranium ore from which the fuel was made. So that's 10,000 years. But really to be safer than that, because some of the radioactive isotopes have much longer half lives, we say that we want to wait either 100,000 years and preferably 1 million years. So we have to design a management strategy for keeping this material safe for a million years, which is totally mind blowing because some of the oldest known human structures are only several thousands of years old. Yeah, I mean, the timescales are beyond anything that humans have ever built, that civilizations have lasted. It is just extraordinary. Why has geological disposal, has this burial system been selected? Because there were other suggestions. I remember conversations, reading about sort of proposals to send this stuff into outer space, to send it to the bottom of the ocean. Why has geological disposal, deep burial, become the option to go for for most of the world? Well, there's now really international consensus amongst scientists as well as policymakers that geological disposal is really the best thing to do with this material. Personally, I like to call it the least worst option because there's not really much useful we can do with this material. But why geological disposal is really because what we need to do is isolate that material from future populations. The only way to really get rid of it is either to blast it into space, which a lot of people always think, well, why don't we just do that? Well, one in four space rockets explodes before it leaves the atmosphere. And so we would end up dispersing radioactive waste finally across the atmosphere, which is not really what we want to do. So the next best option really is isolation deep under the ground. And if we think about it, the uranium that we use to make nuclear fuel, it comes from the Earth. It comes from natural ore bodies that are mined and then converted into nuclear fuel. So essentially what we're doing is we're taking the fuel that came from the rocks and we're returning it back to the rocks. Right So that the sort of the scientific the geological case almost for deep geological disposal for why that will be safe Is that right that we essentially want to put it back to where it came from Yeah, the thing about the deep geosphere is that as geologists, we have a really good understanding of how that's behaved on the timescale of hundreds of millions of years. It's very predictable what happens under the ground. And so we can have very high confidence of what's going to happen over a million year timescale. And we can look to natural analogues. For example, there's a natural uranium ore body in a place called Oklo in Gabon. And this natural ore body, it underwent natural nuclear reaction. So it did the nuclear chain reaction underground all by itself around about 2 billion years ago. And it did it for 100,000 years. And scientists have studied that ore body and they've found that the fission products that were created, those smaller atoms of uranium that split into more radioactive things, they only travelled a matter of centimetres. So we can have very good confidence that disposing of radioactive waste in a geological formation is something that we can predict and understand and will be the best way to isolate radioactive waste from future populations. Right. Well, that's so clearly explained, Claire. Thank you so much. That's OK. Stick with us. Because multiple countries have plans in place to create facilities deep underground to bury their nuclear waste. But one country has managed to get there first and actually build one of these facilities, Finland. Finland plans to deposit its first canisters of spent fuel later this year, later in 2026. And I went to visit the site a few months ago with some specialists from the UK. As we drive northwest from Helsinki, what strikes me about the scenery, apart from lots of trees, is dense grey rock. Some of the main road is cut through the granite. It's beneath that dense bedrock that some of the most hazardous material produced by humanity, highly radioactive spent nuclear fuel, will be buried in a place called Onkalo, which is where we're headed. Oh, why come to Onkalo? It's a really exciting time, probably the most exciting time to come to Onkalo. That's Fiona McEvoy, geologist from the UK's Nuclear Waste Services, who's here on a fact-finding mission, because Oncolo is the world's first deep geological disposal facility for nuclear fuel. The UK plans eventually to build one of its own. We'll probably be one of the last visitors here, actually, in fact. So in a few weeks they'll shut down, and when they shut down, then they'll do their testing, and then it will open for real. And that is phenomenal. It's a watershed moment in reality for the nuclear sector. It's important to the UK, but it's important globally because it is the demonstration that long-lived dangerous waste will be put safely, locked away, you know, for eternity. Disposal holes are drilled in the tunnels using a purpose-built boring machine. At ground level, above the tunnels, is a visitor's centre with an exhibition explaining the whole containment and permanent disposal process. I'm allowed to get inside the exhibits. I'm inside the first test canister for spent nuclear fuel. You can hear I'm in a cylinder of solid copper. And this is one of the canisters that the spent fuel rods are contained inside before they're put underground. We won't see you in. In that time when we started, we were not the first in the world. Sana Mustanen is a geologist and project manager for POSIVA, the company that operates Oncolo. You have UK colleagues here who are learning from what you've done. How has Finland got here before anybody else did? Well, that's a good question. Maybe we are stubborn or whatever, but gradually other countries have had their own problems and we are now the first ones in the world. After this, all tunnels and shafts leading to it will be closed. More than 400 metres beneath our feet is a network of tunnels and underground facilities spanning an area of about two square kilometres. That will be the final destination for waste from Finland's two nuclear power plants. So you are with the helmets and your safety gear, all of you, and then we can go underground. Sanna Mostanin is our guide. I'd been expecting a long drive down the five kilometre corkscrew access tunnel. Instead, we're taking the lift. and I am very keen to press the minus 433 button. Yes, please. Can I? How do we go? I can feel my ears popping. Wow. You can feel the temperature changing. So here we are. I was expecting it to feel a little bit more dramatic than it did. You come down in a lift and it takes less than a minute to go down into bedrock 400 metres down. We are going to first to the car, then we drive a little loop in the technical area, and then we are going to visit the first final disposal or deposition tunnel. So that is our loop today. When our group of Finnish guides and UK visitors arrive arrive at the first final deposition tunnel we can explore on foot. Fiona McEvoy explains why geologically this is such an extraordinary place. So the rocks here are incredibly old, generally across Sweden and Finland. They're some of the oldest rocks in Europe, dating to about 3.2 billion years. Here specifically they're about 1.9 billion. It's completely unweathered and the exact properties that they need here in Finland for disposing it. It's absolutely amazing. How exciting is it for a urologist to be in these tunnels? It doesn't get better. It's amazing. Something all of us audio makers do when we're recording these stories is to capture silence wherever we are. Every silence in every environment is different. So I ask everybody in the group to stay quiet for a minute or so. Inside the bedrock, in a facility that's been created precisely so that it can be closed off and isolated from humanity, there's a deep, unfamiliar silence. That's so quiet, isn't it? It's like complete silence, like silence you don't normally experience. So far, about 10 kilometres of tunnelling has been completed here. But it's only the start. The plan over the next 100 years is to keep digging as the site fills up with waste. With about 40 kilometres of new tunnels planned, space for more than 3,000 canisters of nuclear fuel. Tunnel is 3 metres wide 4 metres in height and some little bit more than 300 meters long And here in the underground we put the canisters into the deposition holes and there will be bentonite in the holes as well. Bentonite is like a clay. Bentonite clay, exactly. And then this whole tunnel is filled with the bentonite clay and the end plug is casted into the beginning of the tunnel and then everything will be safe there. A tunnel dug 400 meters down in the rock, there are holes dug in that tunnel, the canisters are shielded in two layers of metal, then there's a layer of clay, then the whole tunnel is filled with clay and then plugged. Yes, so it's isolated from the nature. The idea is that once you put it here and then almost shut the door on this and it's isolated from nature, from human contact for millennia. This place is designed, is built to be safe and contained for a hundred thousand years. Mankind has never made anything that's lasted that long, I suppose. How can you be confident that once your canisters of spent waste are down here, they are isolated, gone, we can essentially plug the hole and forget about them? My confidence lies there that there is decades of research done for this system. So we know exactly what our bedrock is like and we know what kind of waste we have and then we know what we need to do and for how long actually to keep the waste isolated and that it's going to be safe. So you're pretty confident that this is a secure place to lock away hazardous nuclear waste? Yes, we are. We heard from the geologist, the Finnish geologist at the end of my report there, just how confident the team are that this is a safe option for the, I mean, long term doesn't even cover the timescales that we're talking about, does it, for eternity. You know, how significant is what's happening at Oncolo right now for the rest of the world? Well, Onkolo are paving the way. They're showing what can be done in other countries that have radioactive waste. And they've really spent decades trying to get to this point. And it's really exciting to see that they're going to have their first waste emplacement really soon. What I would say about Finland is that they have quite a unique situation. They're first because they've got things in a very simple way. They have a very stable old geology. so the rocks they can predict very very well and they have only one type of waste they have the spent nuclear fuel just the uranium fuel rods that have come out of the reactor and these are the only things that they're going to be disposing of so they really have a simple case and if it can be proven with a simple case first then we can think about doing it for more complicated types of rocks more complicated types of waste in other countries as well and and i mean And I don't want to dwell on the UK's case in particular, but the UK is quite special in that regard, isn't it? Because it has a very complicated and sort of messy stock of nuclear waste because the first generation of nuclear power started here. Things were not stored and catalogued and really taken care of in the way that's been possible in Finland. So we have different shapes, different sizes, different types of waste. How much more complicated does that make deep geological disposal? It makes it quite a bit more complicated. You're right. We have a bit of a smorgasbord of radioactive waste types, ranging from vitrified waste to cemented waste. There's spent fuel. We've now decided that we're going to be disposing of plutonium as well. There's weird and wonderful exotic fuel types because we innovated a lot of different types of nuclear reactors in the UK. So that does make it more complicated. it does mean that we have to think about designing different types of barrier systems for those types of radioactive waste and also think about exactly how we go about building the repository, the facility, to accept all of those waste types. And which other countries have these facilities planned? Who's furthest ahead behind Finland? Well, Sweden is very closely behind. They will soon be building their facility in exactly the same rock type as the Finnish facility at Oncolo. So they're soon. And then countries who have sites selected already are France, Switzerland and China. So they're going through the permitting process at the moment. and then there are other countries who are just at the policy stage they're looking for a site so that includes the UK and Japan and then there are plenty of other countries I can pick on just a few who don't have a plan at all yet or they're going to wait to decide so the Netherlands is a really good example of that they decided to keep their nuclear waste in an above ground facility for now and then in a hundred years time they're going to decide what to do about it. Professor Claire Corkhill, talking to my colleague Victoria Gill about Finland's pioneering oncolo facility and what it offers the rest of the world with nuclear waste to dispose of. A reminder that you're listening to Inside Science from the BBC World Service. Slimme Technologie op kpn.com slash slimmerwerken. KPN, for a better work in the Netherlands. Starting a business can be overwhelming. You're juggling multiple roles. Designer, marketer, logistics manager. All while bringing your vision to life. Shopify helps millions of business sell online. Build fast with templates and AI descriptions and photos, inventory and shipping. Sign up for your one euro per month trial. and start selling today at Shopify.nl. That's Shopify.nl. It's time to see what you can accomplish with Shopify by your side. Of course, building a facility that you want to last for hundreds of thousands of years comes with an obvious non-engineering-based problem. Who will be around in hundreds or thousands of years and how can you stop them from digging up what you buried and being harmed by it? Earlier, I spoke to journalist Mark Peising, who has written extensively on this topic, and asked, is it better to hide the waste or warn about the waste? Yeah, that's the ultimate dilemma, isn't it? What do you do with this waste? You've got to do something with it, especially the long-term waste. Bury it, hope no one discovers it. And I guess you can try and I know this, what they're trying to do is find areas where there's no mineral resources that anyone would want to poke around there. But the other way is obviously, yeah, trying to put some kind of structure on top, some kind of tell stories, folk stories as a way to keep people. Well either tell them about it or to warn people off I guess of the two approaches OK so what do you think of the strategy of warning people off So the Americans were perhaps the first people to deal with this with a with a WIPP kind of waste depository and I guess they came up with fantastic ideas that feel very in a sense of very natural I suppose because it's kind of our parents telling us off so we had this crown of thorns, huge thorns over the site. That was one idea. Others are this atomic stonehenge with gigantic pillars and earth barriers with secret archives in the middle. Gair Dunlop is a senior lecturer in contemporary art practice at the University of Dundee, who also has, for many years, been co-convener for an international collaboration called the Nuclear Culture Research Group. Sandia Lab in 1993 recommended multiple levels of complexity for response to how to leave things. So some of these levels of complexity involved something called, for example, the spike field. This was huge sculptural angled spikes, leaning stone spikes, and the concept and the art was by someone called Michael Brill. These would be intimidating to approach that physical sense of you shouldn't really be here but the question of course is that wouldn't you want to do something like that if you were hiding something valuable what's the question of value in these terms so again different levels of complexity that are kinds of plaques suggested remember this was the time when the voyager spacecraft went out with pictograms and the idea that that kind of knowledge could be contained in pictograms was quite common so they're almost poetic plaques assuming English will still be understood or transcribable with this place as a place of great degradation etc those kinds of things. Presumably we can't use just nothing at all just you know grassing it over and pretending that nothing's there because if current civilization's anything to go by we have archaeologists and if we think that there's something interesting from an ancient civilization we'll dig down. Yeah yeah I mean I think that's that's the it's wonderful to talk about these great ideas but yeah the experience of say ancient egypt is there's a pyramid there's a structure no one which is odd and big let's dig into it there's a cave there's a structure in the side of the valley and there are curses attached to it let's dig into it and find out so yeah there's a sense of uh you know people just ignore you know the warnings of these structures and just want to find out more about them and dig into them so yeah that that is something there's always in the background and you're wondering whether all these techniques are just going to attract people to these sites. And perhaps it would be better just to cover them over and just try and hopefully everyone will forget about it. I'm involved in a thing called the Nuclear Culture Research Group. So we're looking at a lot of these things. And if you want to look at the more kind of wildcard approaches, Andy Weir's Pazugu. This is a 3D printable marker. And this is going to be put into nuclear sites for potential future post-human paleoarchaeologists, according to Andy. So this thing looks a bit like a glowstick-waving Pokemon. So it'll be 3D printable, it'll be scattered around, and it's based on a figure based on the Assyrian Demon of Contagion. So it looks a bit Pokemon, but slightly scarier. There's another more deep insertion into culture concept called the Atomic Priesthood Project. So the idea is that you establish legend and ritual and then that can have a continuity beyond physical means. So that would lay a sort of false trail. It would lay a set of warnings. And it takes the form of an open-ended archive at the moment, which is just completely available online, the Atomic Priesthood Project. You can look it up. So how involved in any kind of decision-making it will be is very speculative. But out of that comes a project called Cumbrian Alchemy. So those landscapes are linked by a sequence of performance arts and this idea of a priesthood and the kind of shamanistic figure can be something that can embed itself in a culture. It's so interesting that actually one of the most durable ways of telling our descendants not to go there is sort of by creating some sort of nuclear religion. Yeah, absolutely. Yeah, and it's kind of, I suppose people criticise this idea because it's kind of manipulative, but perhaps it might work. I believe this is a world called nuclear semiotics, right? That's right, yeah. So semiotics is about communication, how people communicate to each other. Nuclear semiotics is about how we use everyday communication, really, to tell something much bigger. And that's either the information about what these sites were or to keep people away from them to 500 generations more in the future. My favourite of all this is something called the Raycat solution, which originally came out of some of the early speculation in 1981. It's very, very simple. You engineer cats genetically that change colour in response to radiation. and then you create the culture, the legend and the history which you of course have to embed which is something nobody quite knows how certain cultures take off the same way nobody knows how certain memes take off so anyway, you create the culture, legend or history that if your cat changes colour you should move house down quickly so that's one of the stranger possibilities but you might find some of these things completely implausible but language is, you know, it's at the very edge of language and where philosophy can take us. There you have it. Who would have thought that nuclear waste would take us to the edge of language and philosophy via Pokemon and genetically engineered radiation sensitive Geiger cats? My thanks to Mark Peising and Gair Dunlop and before them, Professor Claire Corkhill. Thoughts or stories to share on this subject? I'd love to know if you live somewhere with a novel approach to your nuclear waste. Please do email insidescience at bbc.co.uk. From Victoria Gill and me, Marnie Chesterton, that's all for now. Bye bye. To be continued... Just on your Netherlands TV.
