"So we've arrived at minus 437m underground." We're inside the only final storage facility for spent nuclear fuel in the world. "There is going to be basically no danger within the next hundreds of thousands of years." This tunnel deep underground is supposed to be the game-changer for nuclear waste. There are a quarter of a million tons of nuclear waste just lying around across the globe. In some cases, leeching toxins into the environment. And nobody really knows exactly what to do with it yet. Except for the Finns. So how did they do it? And does this mean we've solved the nuclear waste problem once and for all? "When I first heard that the Finns were building a nuclear waste deposit site, I thought it would be in the middle of nowhere, maybe in the Arctic circle. But no, it's actually just a three-hour car ride away from Helsinki." In a municipality of almost 10,000 people called Eurajoki. Which also happens to be home to Europe's largest nuclear reactor. The municipality actually bid to host the site and was selected from four possible locations. Construction started in 2004, right next to the power plant. "Sounds quite straight forward, doesn't it? But it's actually really remarkable that this happened." Because a final disposal facility for spent nuclear fuel has to keep highly radioactive waste from leeching into the environment for a couple of hundred thousand years. To put that into perspective, a couple of ice ages will have come and gone in that time. That needs decades of discussions, planning and careful selection of sites and a feat of engineering. Other countries with nuclear power plants have also been looking for their own permanent storage sites, but nobody has even started construction anywhere else. Whether you're pro or anti-nuclear energy, this problem needs a solution fast. Because the waste is piling up in sometimes inadequate interim storage sites worldwide. But not in Finland. After decades of research and construction, the site called "Onkalo," "cave" or "hole" in Finnish, is about to start operating in the next few years. The project is financed by the Finnish nuclear power companies, which are partly owned by the Finnish state. "And we're ready to go!" The trip down takes almost a quarter of an hour. "So we've arrived at - 437m underground." "Yeah, it definitely feels like a cave." All around us is crystalline bedrock, a mixture of granite and a rock called migmatite. And that's the first key to why this place was chosen to store the nuclear waste. The age of the rock is almost two billion years. It's rather unfractured. Rather dry. We don't have a lot of groundwater movements in here. Antti Joutsen is the head geologist at the company responsible for the facility. The host rock needs to be unworthy in the sense that not economical things that future generations would like to dig out from the rock. But finding the right rock is just the first step. Because nuclear waste is unlike any other waste. There are three main types: low-level, intermediate, and high-level waste. Low-level waste is usually stuff that came into contact with radioactive material. Like protective equipment, filters, or medical waste. Intermediate waste is equipment used in nuclear plants or weapons production like pipes or insulating material. This can stay radioactive for a couple of hundred years. They are decontaminated and disposed of in low-level waste sites under or overground. Up to 99% of all nuclear waste falls into that category. The one percent of high-level radioactive waste is the most problematic one. That consists mostly of spent nuclear fuel rods. But it also includes waste from nuclear weapons production. Spent rods still contain lots of energy. Enough to emit heat and remain radioactive for up to a million years. And that waste is sitting in cooling pools or in dry casks around the world. A total of over a quarter of a million metric tons, says the International Atomic Energy Agency. That's as heavy as 26 Eiffel towers. And some of it is leaking radioactive material. Our best solution for handling it safely is burying it deep underground and leaving it to decay for a couple of hundred thousand years until it isn't dangerous anymore. To prevent radioactivity from the rods from leaking in the meantime, it needs to be encased properly. In Finland, the spent fuel rods are sealed into 5-centimeter-thick and around 5-meter-high copper canisters. They are then transported underground with a hoist. Holes are drilled into the bedrock along very long tunnels. The canisters are then put into the holes, as in this demo drilling. "Wow, that's so deep. You can hear my echo there." Then the hole is filled up with bentonite clay, which is also used as cat litter, and can absorb groundwater that might seep in and corrode the copper canister. And, finally, the tunnel is backfilled with the same material and sealed with a 6-meter thick concrete slab. As you can see here in this demonstration tunnel. "This is our first real final deposition tunnel. It's 350 meters long. We can fit around 40 capsules in this tunnel." Those capsules or canisters are the most controversial part of the whole nuclear waste repository. "So it's quite wet here, and groundwater can be dangerous for the canisters, isn't this a problem?" "After all, even though we have minor leakages into the tunnel, the amount of inflow into the tunnel is very, very small, so still good for final disposal." The problem is what happens if the bentonite layer has defects or is damaged and groundwater containing sulfide and hydrogen does reach the canister. Researchers have shown in multiple studies that copper could corrode and the canisters could fail much faster than the company in charge has calculated - possibly already in a time span of decades. Research on this is ongoing and the topic is highly debated in the scientific community. But the stance of the Finnish nuclear safety authority and Posiva is that the uncertainty isn't so high that it would pose a significant risk. And they stress that the canister is just one protective layer of many. "If we have an escape of radionuclides from the disposal canister, then we have the bentonite clay around it. If then some still manage to move on, then we have the 420 meters of rock on top of us. So the radionuclides would need to crawl through some fracture network upwards 420 meters without getting absorbed to the fracture surfaces. It can still work if some of our assumptions might be wrong eventually." Onkalo is meant to house all the future waste of Finland's existing nuclear power plants. The storage site will be gradually expanded for about a century, until it stretches over 50 km. But then it will be sealed permanently, and not touched again. The site will no longer be monitored The overground buildings are to be dismantled. If any additional reactors are built, it is unclear what would happen to their waste. Nor is it clear how future generations will be able to tell that radioactive waste is located here or if it should be kept unmarked. But that's a question for another video. But even so, Finland is way ahead of most nations. Maybe because of their unique mentality. "One role in there might be with the pragmatic mindset of Finnish people. There has been a mutual consensus that we need to take care of the waste. Not to leave them to the future generations. There has been very little opposition from the society." Back above ground, that was confirmed. "No I'm not afraid that anything bad will happen because they are very careful about safety. Everyone here likes nuclear power mostly. We've had [a] good run with our plants. I think it's good. We get more taxes and money from that. And maybe some new people. And for [the] business side, it's good. We have very much money. Eurajoki gets around 20 million euros in property taxes every year from TVO, the company who owns the nuclear power plants and the waste disposal site. Eurajoki's center only has a few thousand inhabitants, but its own healthcare center, nursing home, library and a host of sports facilities. And it is building another sports center for 9 million euros. Vesa Jalonen has been living here for over 50 years and is the municipal government chairman. "People in Finland they think so that because engineers have investigated that for example our regulator STUK, we trust it very, very much." In Finland, power companies are very [transparent]. Always tell us what happens there. We have cooperation groups with TVO and Posiva and I think they are very important. Actually, we can say that we are very proud of that. And that's quite unique. In many other countries, local opposition is one of the biggest hurdles to choosing a final storage site. In the U.S., Yucca Mountain in the deserts of Nevada was abandoned as a proposed site after the State strongly opposed the idea. Germans protested transports of nuclear waste to the planned site in Gorleben for decades until the location was deemed unfit. And the small village of Bure, in France, has become the center of the anti-nuclear movement since it was proposed as a site for radioactive waste. But that does not mean it's impossible to find somewhere that people agree on. Sweden will most likely be the next country to start construction. They were also the ones to originally develop the technology used in Onkalo. The Swedish government recently approved a site in Forsmark, an area also home to a nuclear power plant, like Eurajoki. Switzerland suggested a location very close to the German border. Protests were largely only heard from the German side. The technology behind the final storage facility is more easily transferable. What's happening in Sweden is the best example of that. Canada also has similar rock, and has collaborated with the Swedes and the Finns. Meaning, it could also use similar technology. But geological conditions aren't the same elsewhere. France is planning on storing their waste in clay, which requires different types of barriers and canisters. Germany is considering putting it in old salt mines. Again, a different ball game. And the US is still open to all disposal types after they had to start from square one. So, just copying what has been done in Finland isn't possible everywhere. But selecting sites that already have ties to nuclear energy does seem to work. Communicating with the locals and involving them is another key point. Financial incentives also don't hurt. And being willing to learn on the job and being pragmatic about the waste also helps. "The Finns seem pretty confident they have found a good solution for their own nuclear waste. And I must admit, it seems like the best option out there, even if there a few open questions left." Although you could argue that they should conduct more research before locking in a technology that has to last for up to a million years. "Other countries that lack the unique Finnish combination of pragmatism, politics and geology, are going to find it a lot harder to follow suit though. Thanks for watching. Please subscribe. We post videos like this every Friday."
