Fusion, another step closer?

[Squire Doodad]

In a general sense, we have the means and ability to handle properly set up nuclear reactors, including ones that cannot be used to make bombs in any way shape or form. Some even are functionally foolproof outside of, like, someone else dropping a bomb on them. However, reactors are still politically volatile; while I'd argue other means of energy are better overall, nuclear is much safer and better than it was in the times of Chernobyl.
Here's a pretty good article about it from Soonish:
https://www.smbc-comics.com/soonish/...ter/index.html

[halfeye]

I am strongly opposed to pollution, I personally think toxic waste is more important than greenhouse gases, but that is a quibble. In the long run heat will be a limiting factor, even if we aren't there yet, supposing we eliminate the greenhouse gases and toxic wastes in whichever order.

What was so difficult about parsing this?

I think toxic waste, that is poisons like mercury, some plastics, and DDT and whatever need to be cleaned up. I think we have a longer timeline to sort out greenhouse gases, but we do need to get to them too.

Eventually, if that's all sorted, and population is in the trillions, heat will eventually be a problem, whatever power source we have.

I do still think that widely available fusion power is far nearer 50 years away than 20 years away, even though it was said to be 50 years away 50 years ago.

[Radar]

What was so difficult about parsing this?

I think toxic waste, that is poisons like mercury, some plastics, and DDT and whatever need to be cleaned up. I think we have a longer timeline to sort out greenhouse gases, but we do need to get to them too.

Eventually, if that's all sorted, and population is in the trillions, heat will eventually be a problem, whatever power source we have.

I do still think that widely available fusion power is far nearer 50 years away than 20 years away, even though it was said to be 50 years away 50 years ago.

Unfortunately, we might be already too late to deal with greenhouse gasses before there are severe changes in the climate - once it started rolling (and it does), it is not that easy to stop. I would say we need to deal with both that and toxic wastes right here and now. Getting rid of plastics from the oceans will require some novel approach and without active means is unlikely to ever stop being a problem even if we stop throwing that stuff away.

Heat is a big maybe as 5 orders of magnitude is more than we can actually imagine properly. Currently, the global average is about 350 W of power per person. Ramping it up by 5 orders of magnitude would mean that we would spend 35 MW per each person. Can anyone even think of what could it be used for? If we did have that kind of power at our disposal, setting up industry and habitats on other planets or in space would be trivial (even at far lower power production actually), so way before we reach something like that, we would spread throughout the solar system and the power output would not be confined to Earth.

[Squire Doodad]

What was so difficult about parsing this?

I think toxic waste, that is poisons like mercury, some plastics, and DDT and whatever need to be cleaned up. I think we have a longer timeline to sort out greenhouse gases, but we do need to get to them too.

Okay, I don't know how else to say this, but we're already in the climate apocalypse, or at least having one hell of an appetizer.
California is burning. Oceans are experiencing MASSIVE heat waves. Some towns in the middle east are reaching temperatures during heat waves that are deemed "inhabitable".
And, in spite of it all, there has been...not enough progress made on that front. We're arguably a few years behind where we should be on replacing fossil fuel infrastructure with renewables, though fortunately the renewables themselves are in great shape. There are projects like the one to clean up the Pacific Garbage Patch underway, but there isn't that global sense of unity on it like there was with the ozone problems.

Also, yes, overuse of plastics and toxins in pesticides is part of this problem; fixing GHGs would also involve enough changes to infrastructure that those two can be partially fixed in the process.

We need drastic, ecologically-focused action. Something like the Montreal Protocol, with everyone joining in and making decisive action as soon as possible. This isn't a "we should" or a "my political compass says this", it's a "I want to live in a world where the Amazon is intact" thing.
...yes, this is what keeps me up at night.

[Fyraltari]

Eventually, if that's all sorted, and population is in the trillions, heat will eventually be a problem, whatever power source we have.

Population won't ever reach the trillions, though. The current growth in population is due to the demigraphic transition it's not going to keep up indefinitely.

And even if that were the case, in the centuries after we'd developped mainstream nuclear fusion, we'd start settling other planets anyway.

[halfeye]

Okay, I don't know how else to say this, but we're already in the climate apocalypse, or at least having one hell of an appetizer.
California is burning. Oceans are experiencing MASSIVE heat waves. Some towns in the middle east are reaching temperatures during heat waves that are deemed "inhabitable".
And, in spite of it all, there has been...not enough progress made on that front. We're arguably a few years behind where we should be on replacing fossil fuel infrastructure with renewables, though fortunately the renewables themselves are in great shape. There are projects like the one to clean up the Pacific Garbage Patch underway, but there isn't that global sense of unity on it like there was with the ozone problems.

Also, yes, overuse of plastics and toxins in pesticides is part of this problem; fixing GHGs would also involve enough changes to infrastructure that those two can be partially fixed in the process.

We need drastic, ecologically-focused action. Something like the Montreal Protocol, with everyone joining in and making decisive action as soon as possible. This isn't a "we should" or a "my political compass says this", it's a "I want to live in a world where the Amazon is intact" thing.
...yes, this is what keeps me up at night.

In the very long run, it's going to come to "which humans do we starve to feed the animals?" It aint easy. It also isn't my problem, I'm not going to be here then, and probably neither is anyone else reading this at this time.

Climate change affecting land is one thing, Britain is wet and cold so we have a different perspective on that than hotter places do, but the seas rising 150 metres is something we'll be dead against. The story I'm currently hearing is that it'll take a century to rise one or two metres, then a long time longer for the rest.

Population won't ever reach the trillions, though. The current growth in population is due to the demigraphic transition it's not going to keep up indefinitely.

We don't know that. Poor people keep breeding, it's a valid reaction to being poor. There are countries with a high death rate where the average age is under 30 years old? under 20 years old?

And even if that were the case, in the centuries after we'd developped mainstream nuclear fusion, we'd start settling other planets anyway.

If we can get up into space, coming down to planets again would be a mistake in my view, and we're probably never going to be rich enough to lift a significant proportion of the Earth's population into space, supposing that population hasn't fallen to hundreds.

[Squire Doodad]

In the very long run, it's going to come to "which humans do we starve to feed the animals?" It aint easy. It also isn't my problem, I'm not going to be here then, and probably neither is anyone else reading this at this time.

Climate change affecting land is one thing, Britain is wet and cold so we have a different perspective on that than hotter places do, but the seas rising 150 metres is something we'll be dead against. The story I'm currently hearing is that it'll take a century to rise one or two metres, then a long time longer for the rest.

We don't know that. Poor people keep breeding, it's a valid reaction to being poor. There are countries with a high death rate where the average age is under 30 years old? under 20 years old?

If we can get up into space, coming down to planets again would be a mistake in my view, and we're probably never going to be rich enough to lift a significant proportion of the Earth's population into space, supposing that population hasn't fallen to hundreds.

Okay, wow there is... a lot to unpack here, and frankly the best thing I can say is that you should read up on Malthusian theory, the current impacts of climate change, population growth, and so on. You're certainly not being "stupid" or anything, but there's a lot of recent reports and research you should read up on and take into account.
This is basically my major, but I do not have the energy to go at this blow by blow right now.

Anyone have some of those "# of days above 90 degrees Fahrenheit from 1980-2000 vs 2000-2020" maps handy?

[Rydiro]

Why do people think that fusion reactors solve all our energy needs (fossile fuels, carbon...) when they have no advantage over current fission reactors? On the production side, I ignore the waste aspects for now.

Do you think fusion reactors can be miniaturized to run a car?

[Florian]

Why do people think that fusion reactors solve all our energy needs (fossile fuels, carbon...) when they have no advantage over current fission reactors? On the production side, I ignore the waste aspects for now.

Do you think fusion reactors can be miniaturized to run a car?

Let me start with a joke: Someone tried to calculate the energy consumption of a kangaroo. They calculated the initial hop, were shocked at how much energy that consumes and came to the conclusion that kangaroos should have died out, because their hopping to a source of food would consume more energy then thr food would generate. They overlooked one critical piece of information: Once the kangaroo made the initial hop and is in motion, all subsequent hops consume a negligible amount of energy.....

That's the thought behind a fusion reactor: Start the chain reaction once, keep it going with minimal efford and ressources.

[factotum]

Why do people think that fusion reactors solve all our energy needs (fossile fuels, carbon...) when they have no advantage over current fission reactors?

A fission reactor requires difficult to find stuff like uranium to work, and there's a limited supply of that. It's not as limited as fossil fuels, but nonetheless, will still run out some day. Fusion, on the other hand, uses isotopes of hydrogen, which is the most common element in the Universe. Even when the isotopes you're using make up only 0.016% percent of all the available hydrogen, there's so *much* available hydrogen that it might as well be unlimited. That's why fusion has a significant advantage over fission. Not to mention, it doesn't yet (and hopefully never will) have the same negative opinion among the general populace that fission does.

[Cikomyr2]

Also, fission relies on existing unstable elements being bombarded to create a chain reaction that generates energy and has to be carefully monitored and controlled so it doesnt get out of control. Badly designed fission reactors had accident when these runaway processes happened and had large consequences.

You cannot have a "runaway process" with Fusion, since its all about feeding it your fuel (variants of hydrogen). You cut the supply, you cut the reaction. And the supply itself is not hazardous to health to stock or transport the way uranium is.

[Radar]

Also, fission relies on existing unstable elements being bombarded to create a chain reaction that generates energy and has to be carefully monitored and controlled so it doesnt get out of control. Badly designed fission reactors had accident when these runaway processes happened and had large consequences.

You cannot have a "runaway process" with Fusion, since its all about feeding it your fuel (variants of hydrogen). You cut the supply, you cut the reaction. And the supply itself is not hazardous to health to stock or transport the way uranium is.

Reaction getting out of control is not much of an issue unless you make bad design choices that are currently blatantly obvious. There is still the natural decay to deal with: even with fully suppressed chain reaction (so no or almost no secondary fissions) a typical 1 GW reactor will still produce up to 50 MW of heat so is in need of active cooling.

One thing to mention is that while spent fuel from a fusion reactor will not be radioactive, the reactor itself will become irradiated over time, so used parts will have to be dealt with just like any other nuclear waste. Obviously there will be far less of it than in the case of a fission reactor.

[Lord Torath]

Reaction getting out of control is not much of an issue unless you make bad design choices that are currently blatantly obvious. There is still the natural decay to deal with: even with fully suppressed chain reaction (so no or almost no secondary fissions) a typical 1 GW reactor will still produce up to 50 MW of heat so is in need of active cooling.

One thing to mention is that while spent fuel from a fusion reactor will not be radioactive, the reactor itself will become irradiated over time, so used parts will have to be dealt with just like any other nuclear waste. Obviously there will be far less of it than in the case of a fission reactor.

I thought I read something in the recent news stories that ITER's inside surface was going to be made/coated with a material that would not absorb the radioactive particles, and thus would not become irradiated.

[Radar]

I thought I read something in the recent news stories that ITER's inside surface was going to be made/coated with a material that would not absorb the radioactive particles, and thus would not become irradiated.

That I did not hear of frankly. Would be a huge improvement if it works as intended. There is however a question, how well those materials deal with radiation the same way as nothing is for example fire-proof - just fire-resistant.

[Mastikator]

Why do people think that fusion reactors solve all our energy needs (fossile fuels, carbon...) when they have no advantage over current fission reactors? On the production side, I ignore the waste aspects for now.

Do you think fusion reactors can be miniaturized to run a car?

It doesn't have the same bad PR that plague fission power (which is really the biggest draw back to fission- public outcry)

[Quizatzhaderac]

I thought I read something in the recent news stories that ITER's inside surface was going to be made/coated with a material that would not absorb the radioactive particles, and thus would not become irradiated.

ITERS's inside surface will be covered with ceramics made with lithium. When lithium absorbs neutrons, it releases energy, helium, and tritium.

This is important as we'd need a better source of tritium if we want to supply fuel to many fusion reactors. In a way, lithium is the real fuel being consumed by the reactor.

Tritium is radioactive, however the plan is to be able to capture the tritium so produced. The other materials used in the surface (mostly lead, but it's one of things being changed for experiment's sake) are being chosen so that no other radioactive things are produced.

[Cikomyr2]

It doesn't have the same bad PR that plague fission power (which is really the biggest draw back to fission- public outcry)

Said PR was caused by previously mentioned bad design that caused previously mentioned runaway reactions.

You dont hear of oil power plans or coal where they catastrophically lost control of the situation and now the land is unlivable for the next 300 years

[Beni-Kujaku]

ITERS's inside surface will be covered with ceramics made with lithium. When lithium absorbs neutrons, it releases energy, helium, and tritium.

This is important as we'd need a better source of tritium if we want to supply fuel to many fusion reactors. In a way, lithium is the real fuel being consumed by the reactor.

Tritium is radioactive, however the plan is to be able to capture the tritium so produced. The other materials used in the surface (mostly lead, but it's one of things being changed for experiment's sake) are being chosen so that no other radioactive things are produced.

This. In the end, the irradiation of the reactor coating is what really keeps the reactor running. Obviously it will still need to be eventually replaced, but much more easily than a fission reactor, as you can easily have the reaction die out by simply not putting deuterium in there, while fission reaction are so self-sustaining that they require extreme care to be disassembled.

[Rydiro]

Said PR was caused by previously mentioned bad design that caused previously mentioned runaway reactions.

You dont hear of oil power plans or coal where they catastrophically lost control of the situation and now the land is unlivable for the next 300 years

But you have heared of oil spills and the hellscape that is burning coal mines in china?
Kinda unlivable too.

[factotum]

Said PR was caused by previously mentioned bad design that caused previously mentioned runaway reactions.

You dont hear of oil power plans or coal where they catastrophically lost control of the situation and now the land is unlivable for the next 300 years

https://en.wikipedia.org/wiki/Centralia_mine_fire

[Quizatzhaderac]

...you can easily have the reaction die out by simply not putting deuterium in there,....

Actually, I think it might just be as easy as not continuing to actively heat the plasma. Most of the energy produced by fusion is in the neutrons which will always shoot out of the plasma and into the wall.

The rest is in the alpha particles, which will have much, much more kinetic energy than the rest of the plasma, and (I think) be able to break magnetic confinement.

But you have heared of oil spills and the hellscape that is burning coal mines in china?
Kinda unlivable too.

No need to go to China. There's a town in the US that's been uninhabitable for 60 years since a coal mining accident.

[Mastikator]

Said PR was caused by previously mentioned bad design that caused previously mentioned runaway reactions.

You dont hear of oil power plans or coal where they catastrophically lost control of the situation and now the land is unlivable for the next 300 years

The difference in PR between nuclear and coal is like the difference in PR between terrorism and smoking. One might have you terrified, the other is literally murdering you and everyone you love in the most horrible and slow way imaginable.

[Radar]

The difference in PR between nuclear and coal is like the difference in PR between terrorism and smoking. One might have you terrified, the other is literally murdering you and everyone you love in the most horrible and slow way imaginable.

This comparison hits the nail right on its head. I could not put it to words better than this.

[Eldan]

No need to go to China. There's a town in the US that's been uninhabitable for 60 years since a coal mining accident.

Not only that, but most wildlife in Chernobyl is actually doing fine. Better than before, even, because there's no humans there, killing them. Meanwhile, coal fires and oil spills kill everything.

[Vahnavoi]

The Wikipedia page for energy accidents includes a graph showing hypothetical deaths if world's energy demands were met by a single source. Fossil fuels are far worse than fission.

The most environmentally damaging part of fission is digging the fuel out of the ground, both due to tonnage of earth that has to be moved and because the actual moving is still mainly powered by fossil fuels. The handling and transportation of fissive material, even of depleted material, is a footnote. Due to fissive material being solid metal and having high density (both physically and in terms of energy), transporting and containing it is actually easier than transporting various liquid and gaseous fossil fuels, nevermind other chemical pollutants. Even after you've put the fissive material in a reactor and started a chain-reaction, I'd argue it's still less volatile than coal.

[halfeye]

The Wikipedia page for energy accidents includes a graph showing hypothetical deaths if world's energy demands were met by a single source. Fossil fuels are far worse than fission.

The most environmentally damaging part of fission is digging the fuel out of the ground, both due to tonnage of earth that has to be moved and because the actual moving is still mainly powered by fossil fuels. The handling and transportation of fissive material, even of depleted material, is a footnote. Due to fissive material being solid metal and having high density (both physically and in terms of energy), transporting and containing it is actually easier than transporting various liquid and gaseous fossil fuels, nevermind other chemical pollutants. Even after you've put the fissive material in a reactor and started a chain-reaction, I'd argue it's still less volatile than coal.

It may be less volatile (I'd suggest that boiling isn't really the problem anyway, unless we get to a stage much worse than Chernobyl, and coal usually burns before it boils) at the moment, but in a hundred years?

[factotum]

The attitude toward nuclear fission always strikes me as odd. Yes, if something goes wrong then things can go very wrong indeed with nuclear. Same applies to plane flights, though--any individual plane crash can kill an awful lot of people, but flying is still statistically the safest way to travel, because so few major crashes actually happen. Heck, there was one year quite recently (2017) where only 12 people worldwide (of all the millions who travelled that year) died in plane crashes--more people than that get killed in an average week on the roads. Yet people still fly quite happily.

[Peelee]

The attitude toward nuclear fission always strikes me as odd. Yes, if something goes wrong then things can go very wrong indeed with nuclear. Same applies to plane flights, though--any individual plane crash can kill an awful lot of people, but flying is still statistically the safest way to travel, because so few major crashes actually happen. Heck, there was one year quite recently (2017) where only 12 people worldwide (of all the millions who travelled that year) died in plane crashes--more people than that get killed in an average week on the roads. Yet people still fly quite happily.

I figure it's more of a NIMBY thing.

[Lord Torath]

Heck, there was one year quite recently (2017) where only 12 people worldwide (of all the millions who traveled that year) died in plane crashes--more people than that get killed in an average week day on the roads. Yet people still fly quite happily.

Fixed that for you!

There's another type of fission reactor called a "pebble bed" reactor, which is much safer that the control-rod version commonly in place (from what I remember from reading from Physics for Future Presidents).

There's a lot of hype about handling the radioactive waste, and it is a problem, but not one without a feasible solution - bury it in stable rock formations deep underground. They don't even need to be leak free, just leak less than the ambient radiation.

Regarding Chernobyl, I remember reading reports that the leaf-litter there was not breaking down, due to most of the microbes in the area being killed by the fallout. Which means that a good fire in the region could burn long and hot, releasing huges amount of radioactive smoke. Which, yes, will be a problem, but again, less of a problem than the coal smoke we get every year.

All that said, if we can get Fusion working, I think it'll be miles better than fission.

[Vahnavoi]

It may be less volatile (I'd suggest that boiling isn't really the problem anyway, unless we get to a stage much worse than Chernobyl, and coal usually burns before it boils) at the moment, but in a hundred years?

Volatility means chance of stuff blowing up at moment's notice, which is something uranium rarely does even in an out-of-control reactor, but coal dust will do readily where ever it's allowed to mix with normal air.

Long-term issues with radioactivity are not a matter of volatility at all - there the correct comparison is to long-term issues with carbon dioxide and other chemical emissions caused by burning coal. Depleted uranium is horribly toxic, but not particularly volatile.