Name: 【地層処分の科学】1-3. ガラス固化の利点
Uploaded: 2026-01-03T03:25:25.000Z
Duration: 18 min 1 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

So I am now talking about some experience.

This borosilicate glass you see at the very top here, in a fractured glass, shear glass block, a small block.

So typically such a glass can be fabricated in large cylinders.

You see here, this is a cylinder like it is used a container or stainless steel, which is I would say about 1 meter high or 1 meter 10 high.

And you fill it by a glass which is melting down and is pouring inside of the container.

And you see at the bottom some kind of a glass melt.

And this then once it is filled up, it will be closed.

Very hot means the melt is about 1200 degree.

When it is poured into the container, it will slowly cool down in a period of maybe two days or so, until it has at some time room temperature.

But this cooling down fractures the glass.

So the center line temperature is higher than the periphery.

So so there's mechanical stress and so on, and the glass will be fractured.

But this is part of the radioactive glass.

This is not necessary fault or something like this.

That's a radioactive waste glass which we want to dispose of and so on.

Now, this borosilicate glass has lots of industrial experience.

I would say since about 40 years or 35 years or so.

For example, the Savannah river defense waste processing facilities in the US in the south is world's largest heaters for glasses.

And then it's poured into canisters of maybe 4 meters high, very big canisters.

And they produced about 8,000 tons of glass in the meantime since about 25 years or so.

But defense waste glass comes from the processing of the nuclear fuel used for deriving plutonium for the weapons production.

In France we use the nuclear reactions for making electricity.

And here we have industrial production of nuclear fuel and producing the energy.

And then the waste, the waste glass is produced.

And here you see the number of containers per year.

It is about since 2016, where we had already about 15,000 containers.

So we are somewhere here at about 20,000 containers over time.

And now then there needs, of course, storage facilities.

What you see here, this more darker color here and.

And the more lighter color, the blue one here.

These are different storage facilities which needs to be built or which are built already over time.

it is relatively compact and can probably stay for some hundred years or so until somebody puts it into a geological repository of nuclear waste, to which I will come later to explain this.

So this production process of the radioactive waste glass is going is shown here in this diagram.

You see there's many glasses, maybe 10 or eight glass cylinders put on top, each one.

On the other there's some concrete around for the shielding and all of this.

They just on the top surface there are people staying.

And then the glass is put down each time for protection.

You see here these glass cylinders made filled up with glass and the stainless steam container around.

We start with nuclear fuel reprocessing, which means that we have nuclear fuel which we put in nitric acid.

And the nitric acid dissolves the nuclear fuel, the cladding or the hulls of the fuel will somehow be removed.

And then we have dissolved radionuclides.

And then the plutonium and the uranium is separated to make new fuel.

And the rest, the fission products which I described at the beginning, these fission products will somehow be separated.

And once they are separated, they will put into fission product concentrate.

Additives is for example, this silicon oxide, aluminum oxide, sodium oxide and so on, which we put in here at the top.

And in this way there is waste which is efficient products and there is inactive additives.

I would say maybe 20% of waste and 80% of additives.

And then they are mixed here at this stage.

And then these fission products are in nitric acid.

So this is a nitric acid solution which is added up with very lots of nitric acid.

And then it flows through some calcination process there.

The water and the nitric acids are evaporated and the gases which are produced are condensed and the liquids are in.

And there's some gas filters and so on, so that there's not so much that the environment is protected.

I will not go over very much in detail, but this calcinate, maybe this is a rotating calcinator.

And the dry powder now of which includes still these additives of silicon dioxide, aluminum oxide and calcium, maybe sodium and so on.

Boron in particular boron, since we want to make a borosilicate glass, it's boron oxide which is put in there.

And then the fission product, as I said, about 20% and then this goes now down in this melter and here the temperature is much.

Now it's a dry product which enters into the melter.

So the water is evaporated, nitric acid is evaporated.

Now you are in this melter and in this melter there the temperature will be much higher.

Like in this calcinator here, this is about 1500°.

So at this temperature these solid products will fuse, they will become a melt.

And then this melt when it has a sufficient liquid.

Liquid when it is liquid and with some viscosity.

I would say it's just for having experience.

It's not a liquid like water, it's more viscous liquid like honey.

And then it can just can flow down into glass, into containers.

The glass is poured and the containers, then the containers need to stay about two days or so and to cool down sufficiently that would be controlled and so on.

And then they would put into this storage facility.

Storage maybe for some 50 or 60, 70 years they can be stored.

And with time they cool down to probably not to room temperature.

They're still hotter than room temperature because radioactive decay produces lots of heat.

You see this here, that the thermal power over the years, it takes 100 years to go from some high 2000 watt or so down to lower values.

And you see here the temperatures on this bottom diagram going from about 400 degrees during production, just from even the wall temperature of the containers is 300 degrees, very high.

But if you wait now about 20 years, the wall temperature may still be higher than 100 degrees.

And the center line temperatures may be even higher.

Now even after hundreds years is still higher than 50 degrees.

Then even when you do later on something, for example, putting it into a repository for radioactive waste, there's always a heat there.

Subtitles ListPlay Video

【地層処分の科学】1-3. ガラス固化の利点

process

material

period

term