Name: 【地層処分の科学】1-4. ガラス固化体の埋設方法
Uploaded: 2026-01-03T03:30:22.000Z
Duration: 8 min 49 s
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So in the long run, it is necessary to isolate the radioactive waste in deep geological formations.

That means here we need people to construct, of course, such a repository.

But this should be stable for hundreds of thousands to millions of years.

And that means here we don't need people to permanently check if the container is tight and things like that.

It is a formation which is 100 million years old or 150 million years old, and

during this period has never been dissolved by water and so on.

This is relatively dry and water transport can only go by, by diffusion.

And the water, the age of the groundwater in this area is in the areas of some millions of years.

And then one needs to drill, of course, a shaft there.

One needs to construct the repository, as you see here in this formation.

But once it is in, now we can put the glass inside, in here.

And then this would be very nice, isolated.

And even if we put very soluble materials in, they would be isolated from the human environment for millions of years.

Just because the transport of water, of groundwater to the environment takes such long period.

And essentially contact by groundwater or by pore water of the clay is the only way by which radionuclates could come back to the human accessible environment of future generations and so on.

So placing the glass at some depths in such a disposal site is maybe 500 meters depth.

Of course, needs to be constructed repository systems.

We need galleries to have access to disposal places.

Then we need to drill disposal plates where we can put the waste in.

For example, this is a container with the glass, which you have seen before.

And this is now surrounded by another canister around which is maybe about 5 centimeters of iron.

And this iron container with a glass will be put into some, into some vaults.

And then we drill maybe a large hole and put them vertically or horizontally, like in this case, in.

And then the glasses could be filled again, closed by concrete and so on, or by clay materials.

And then this would be isolated in principle forever.

Once it is there, this, of course, heat generation and the heat generation is continuing.

You have seen that even after hundreds of years, there is still high heat.

So one needs to space glass containers here, maybe one here, maybe another one, and so on.

So they need to be spaced at some distances so that the heat does not get higher than the temperature, maximum temperature allowed for such a repository, maybe 100 degrees.

You don't want to go too much higher, just because then there may be mineralogical transformations or fractures and things like that in the repository rock, which one wants to avoid.

And once the repository closed, the question is, are the radionuclides really then immobilized forever?

The only way by which radionuclides from the glass could eventually come back into the human accessible environment is by groundwater.

Now, as I said before, the groundwater movement, the groundwater is very old.

And the time from the waste disposal place to the environment may take some million of years to go there.

In clay rock, of course, water is omnipresent.

And once the container will be corroded and the container may last 10,000 years and there may be corrosion products and the container will break at some time.

This depends on the choice of the container material and how long a container will last.

But just a good number today, I think is 10,000 years.

Even if in some repositories, like in Sweden, they can even be million years stable copper containers.

But here in France, for example, we use iron containers.

Now, after 10,000 years, then this already, during the first 10,000 years is already very nice because now we have a protection of the glass and of the radionuclides inside of the glass for at least 300 generations.

Humanity has never produced something which is sustainable for such long period of time.

Some dangerous radionuclides like cesium 137 or iodine 29, iodine 137 or the strontium 90, they are decayed.

After 10,000 years, they're largely decayed.

So there's nothing left from these radionuclides there.

And that means they cannot go to the human accessible environment.

Plutonium will also be quite a bit decayed.

Americium is entirely decayed, and so on.

But there are still some radionuclides which are there and which have a longer half half life, like iodine129, have a half life of some tens of millions of years takes much.

They will not decay in the period by which the container breaks.

So after the container breach, the water may come in contact with glass.

This is pore water and leading to some slow corrosion of the glass and and to some dissolution of the radionuclide.

And the dissolved radionuclides may slowly be transported to the environment by where humans are living.

And humans may take some water from irrigating fields or for food and so on, and

But such a process may take up to millions of years until this contamination may occur.

And one needs to make sure that the quantity of radioactivity which is inside of this pore water is sufficiently low so that it will never do harm even after millions of years.