Humans have been taking  advantage of radioactivity for more than a century now, in  countless ways both big and small, good and bad, smart and… less smart.

And so over time, we’ve had  to deal with ever-increasing amounts of radioactive waste,  in lots of different forms. Like, some of the biggest  challenges in working out how to use radiation effectively  are really about how to store that material safely  once it’s served its purpose.

And some of the answers to that particular problem are a lot weirder than you’d think. [♪INTRO] First, a quick recap of  what radioactivity even is. There are all kinds of atoms out  there, and some are more stable than others. And those  unstable ones are prone to just spontaneously breaking down into  some more stable kinds of atoms, which also releases a bunch  of energy from that atom.

Some types of radiation release  enough energy that it can knock electrons off atoms of other things,  which is called ionizing radiation. Too much of that can damage your DNA, leading to harmful mutations and even cancers. We’re exposed to radiation all the  time at low doses in everyday life.

Phones don’t emit the harmful  kind, but weirdly, bananas do. Just in miniscule, totally safe amounts. It’s really only when we’re exposed to human-made, artificially high levels of ionizing  radiation that things get dangerous.

Because these radioactive  substances are constantly breaking down and decaying, that  means that with enough time, a dangerous radioactive thing  will release enough energy that it becomes a not-dangerous,  not-radioactive thing. That amount of time can be measured  in a half-life, which is how long it takes a sample of that type  of material to break down by half. Different radioactive sources can  remain dangerous for different lengths of time, from a few  microseconds to millions of years.

And the length of that  half-life is just one of the crucial factors in figuring  out just what to do with your radioactive stuff when you’re done with it. When we talk about radioactive waste, there’s usually one thing that  comes to mind: Power plants. How nuclear power plants generate  their juice is complicated and we don’t have time to get into  all the details, but the jist is that they use rods of a radioactive  material and immerse them in water.

The decay of all those atoms  releases energy in the form of heat. A typical nuclear power plant  is set up to harness that heat by keeping the fuel rods underwater, using the steam to run a generator,  and boom! Electricity.

But these nuclear fuel rods only  last for a few years before they lose their oomph, and they need  to get swapped out for fresh ones. Which means, you end up with radioactive rods that you need to store…. Somewhere.

The storage of spent fuel for the reactors actually happens in several stages. And the first stage looks like what you do with the fuel rods when you’re using them. Once they’re past their prime, the fuel rods are put in a pool of water at the plant.

These pools are usually about  40-feet deep and lined with steel. Typically they’ll spend around five years in these water-beds before the next stage. But even though the rods aren’t  radioactive enough to be used as fuel, they’re still, you know, highly radioactive.

So the pool is also filled  with materials like boron that are good at absorbing  radiation from the rods. After a rod has decayed enough, it’s moved to what’s called dry cask storage. Essentially these are just big metal cylinders, but those are less fun to talk  about, so let’s stick to the pools.

These pools are actually pretty  safe, because along with that boron, the water itself is surprisingly  good at blocking radioactivity. It’s been claimed that swimming at the top of a spent fuel pool may not be especially dangerous. Since the fuel rods are at the very bottom, most of the radiation is shielded  and can’t reach the surface, meaning that you won’t get hit by much of it hanging out at surface level.

But please, do not try this at home. Nuclear pools are fine for the short term. But there have been plenty  of debates over the years about how to store nuclear  waste for the super-long-term.

Some substances will remain radioactive for thousands or even millions of years. So even if you store them in a cave somewhere, it might not stay there. Even if the cave is dry and  far from groundwater now, maybe in a million years that won’t be the case, and you’ll have toxic waste mixing  with the water people drink.

Or, you know, the post-human  robo-cyborg-alien people. I don’t know. It’s hard to predict the future!

Anyway, the point is that  you need a way to make that waste harder to leak into ground  water or get tampered with. So, one invention that  people use today to help keep the waste safe for extreme times  is to turn the waste into glass, in a process called vitrification. Since the 1990s, the US military has used this process to treat some of  its vintage nuclear waste.

They went back and processed their nuclear waste from weapons production in  World War II and the Cold War, a nd managed to vitrify that too. And in 2026, vitrification  is set to begin at one of the US’s largest nuclear  waste facilities, a site in Washington State that dates  back to the Manhattan Project. So, how do you turn waste into  glass?

Well, it’s a simple recipe. You just dry out your liquid  radioactive waste into a powder, and add that powder to molten glass in a smelter, with just a pinch of glass-forming  additives for seasoning. Then, pour the molten glass into  a container and let it cool.

Once the glass has solidified,  weld the container shut and put it in the cave for  two to three eternities. Voila! One nuclear glass cake.

The idea is that the formerly-liquid  waste is now safely mixed in with the glass in solid form,  meaning it’s unable to leak into its surroundings, even  over geological timescales. Or at least, that’s the hope… because it’s kind of impossible  to know for sure if the glass will remain stable that long without  testing it for a loooong time. In fact, one UK university has been studying this process in a decades-long experiment, and the intention is to run it for 500 years more.

So, we’ll report back once we see the results. As long as it’s still people on  Earth, and not the robo-cyborgs. But we use radiation in  plenty of other places besides power plants or weapons.

It’s  also vital in medical settings, from diagnostics to treatments. Unlike in power plants, the radioactive materials used in hospitals tend not  to have very long half-lives. For instance, technetium is used as a tracer for doctors to visualize how well  certain organs are functioning, based on how much of it they absorb.

Its half-life is about six hours,  which is why it’s not such a big deal to go putting it in patients,  and objects contaminated with technetium can usually be safely  disposed of as normal medical waste. But if medical radioactive  waste has a longer half-life, say, a few weeks, it needs  to be stored for longer. One study recommended storing it in a safe storage container like a lead-lined  room for about ten half-lives, or until about 0.1% of the  radioactivity is still around.

But some medically important radioactive stuff stays around for a lot longer. Cobalt-60, which is used to sterilize medical  equipment and to treat cancer, has a half-life of five years. So while you’d think that that means  we shouldn’t just store it in our hospitals when we’re done with it,  that’s still exactly what we’re doing.

See, while there are strict  guidelines for handling medical radioactive waste,  they can be a bit inconsistent. But that only matters if  you’re handling that waste. And if you’re just leaving it  alone in a big empty room….

No handling, no problem. That may sound bad, but it’s actually pretty safe. The rooms are usually lined  to hold the radiation in, so it would only be a problem if you hung out inside the room for a while.

Just make sure you don’t get  lost looking for the bathroom. Now, researching all these  storage methods needs funding, and so do we. So here’s a quick ad.

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Incogni helps you stay safe on the internet so you can keep finding  cool stuff like this video! You might have noticed that a lot  of the items in this list basically boil down to ‘leave the waste  somewhere and wait for it to decay’. That’s fine, if it’s done in a controlled way.

But sometimes the waste gets left  around in a… not-so controlled way. Which is how you get stories of  radioactive waste just being dumped into random bodies of water, with  pretty devastating consequences. It’s happened in several countries  over the decades, including our own.

See, the processes used to mine uranium can leave behind solid radioactive waste, called tailings, and liquid radioactive waste, called raffinates. And certain kinds of uranium  mining projects leave the waste in specially designed ponds called  impoundments on the site of the mine. Now, this isn’t quite as  irresponsible as it sounds.

As long as the site is isolated,  observed, and protected, the harm can be reduced. And like we said before, water is a good radiation blocker. Plus, when uranium decays into radium, that radium will decay into a gas called radon.

So that means that most of the  radioactive waste will just float off. Of course, if you’re not convinced by how safe that all sounds, well, you shouldn’t be. Because the problem with both of these types of waste is that they don’t  always stay where you put them.

Raffinates can seep into  groundwater, and the dust from the tailings can be carried by wind.  Which is as bad as it sounds. Unfortunately, some Navajo  communities have been severely impacted by improperly  cleaned-up former uranium mines. Researchers have speculated  that a bump in cancer rates in these communities could be  linked to the nearby mines.

One paper looking at who had  high levels of uranium found that 27% of Navajo study participants  had high levels of uranium in their bodies, compared to just  5% in the general US population. The cleanup of the mines, and the  fight for justice, are still ongoing. So let that be a lesson to you –  when it comes to radioactive waste, the answer is not to set it and forget it.

Our last unconventional storage  method isn’t about where radioactive  sources are stored, but where  beams of radiation are dumped. We’re talking about the Large Hadron Collider: the gigantic underground particle physics experiment headquartered in Switzerland. The scientists in this  facility do experiments using beams of energy that are,  like, unfathomably powerful.

And they use these beams to accelerate subatomic particles to just barely under the speed of light. Particles are emitted in  every radioactive process, like uranium decaying into radium. But the particles in the LHC can  have tens of millions of times more energy than the particles  from those other, normal processes.

So while the particles of the  LHC aren’t the same as the normal kinds of radioactive sources  we’ve been talking about, they’re still a form of radiation,  and they’re extremely dangerous. A single beam of LHC particles  can together have more energy than an intercity  train moving at max speed. That’s dangerous even before  you factor in the radioactivity!

So where do the scientists at the LHC send that radiation after it’s done  being used for experiments? They use cylindrical slabs hooked up to the main accelerator ring, in a  process called beam dumping. These slabs function as sort of off-ramps, where the beam traffic can be  redirected after it’s done being used.

The beam dumps are made of graphite,  wrapped in stainless steel, and surrounded by layers of  concrete and iron shielding blocks to further prevent radiation leakage. And yeah, the slabs become highly  radioactive after heavy use. Being hit by so much  radioactive energy will do that.

During a long shutdown a few years ago, the LHC conducted a sort of  autopsy of some beam dumps and found significant radiation coming from them. So they had to dispose of those graphite blocks the same way nuclear power plant materials are. Oh, and besides radiation concerns, the blocks need to withstand immense heat fluxes – the LHC beams can heat them up by as much as 1500° C in as little as 100 microseconds.

That autopsy found significant  cracks in parts of the beam dumps, underscoring just how powerful  these particle beams can be. So these beam dumps are one of the most crucial and under-talked about parts of the LHC. Who knew that a few blocks  of graphite were so special?

Figuring out exactly how and where to store the world’s radioactive waste is a huge challenge. Whether that’s for the  short-term like in hospitals, or for the extremely long-term. Radiation is scary to think about,  and it’s just plain hard to plan for something tens of thousands, or  even millions of years from now on.

Which is why we need to store it all safely, if only to protect the robo-cyborgs of the future. [♪OUTRO]