5 ms·

There are several advantages: A fusion reactor doesn't create create long-lived radioactive waste (or any kind of pollution). A fusion reactor cannot be used

There are several advantages: A fusion reactor doesn't create create long-lived radioactive waste (or any kind of pollution). A fusion reactor cannot be used to create nuclear weapons. A fusion reactor doesn't require any form of mining for it's fuel. A fusion reactor cannot meltdown in any way. Due to these inherent safety features, the costs associated with the regulation and engineering a fusion power plant could be much lower than a fission plant.

gizmondo 6y ago
It will be easy to use neutrons from DT fusion to get weapon-grade plutonium. This may be easier to police, i.e. "there should be no uranium nowhere near a fusion plant", but that's a much subtler statement. And of course mining for lithium as a fuel is still necessary, so you should perhaps say "no additional mining" or something.
- willis936 6y ago
  The need for lithium is a valid point. The amount required for fuel is very small though. A 1 GW plant would use more on initial filling than a 30 year lifetime of refilling and even that first filling would be on the order of a metric ton (unverified ballpark, dependent on reactor size, blanket thickness, and plumbing overhead). 80,000 metric tons of lithium are mined each year. We consume about 18 TW. So I estimate that converting all electricity sources to fusion would use about 1/4 of a year’s worth of lithium, but would be enough to make 30 year plants, which would still have most of their lithium left over for recycling/reuse afterwards.
- pfdietz 6y ago
  And enriching lithium is necessary. A single ARC reactor would use a good fraction of all the 6Li produced for the US thermonuclear weapons program. The tritium produced in a fusion reactor program would make it much easier to engineer high yield fission bombs, via boosting.
- rnhmjoj 6y ago
  > And of course mining for lithium as a fuel is still necessary, so you should perhaps say "no additional mining" or something. True, but the quantity of lithium required to breed tritium for power generation is ridiculously low. Operating a DEMO-like reactor for 30 years would consume 2 tons of lithium, which is nothing compared to the annual consumption for battery manufacturing (around 30000 tons).
  - pfdietz 6y ago
    The blanket of DEMO, if using PbLi eutectic, would require 52 tonnes of 6Li. In addition to the raw lithium itself, building even a single reactor like DEMO would require maturing a new 6Li separation technology (the old one caused unacceptable mercury pollution) and industrializing it. https://www.sciencedirect.com/science/article/pii/S092037961930835X https://www.sciencedirect.com/science/article/pii/S092037961...
- nickik 6y ago
  You can not actually police that sort of thing. Thorium is literally everywhere in the earth core. You could basically dig hole right next to your fusion reactor and mine Thorium right out of it, expose it to neutrons and create Uranium-233.
bruckie 6y ago
I suspect a reactor that uses FLiBe can produce pollution: the BeF2 in the solution is toxic, and presumably would have to be replaced periodically. https://en.wikipedia.org/wiki/Beryllium_fluoride#Safety https://en.wikipedia.org/wiki/Beryllium_fluoride#Safety
- pfdietz 6y ago
  If the Be is not recycled then Be consumption becomes unacceptable. A single ARC reactor (2014 paper) would use 40% of the world's annual production of the element.
nickik 6y ago
> A fusion reactor doesn't create create long-lived radioactive waste (or any kind of pollution). It can create things that take 100 years, a closed cycle thorium breeder takes 200-300 years. And the waste from that process is actually quite useful to extract isotopes for medical, nuclear batteries and other applications. > A fusion reactor cannot be used to create nuclear weapons. That is just flat wrong. Most fusion reactors that are considered today absolutely can be used to create nuclear weapons. I would argue starting a nuclear weapons program if you have control over a fusion reactor is far easier compared to when you have a thorium breeder. While it is possible in theory, in practice nobody would ever do it. Your whole workforce would suffer from to much radiation and because of certain other parts of the material, it would be incredibly easy to track in terms of proliferation. This is a buggy-men, and would still be with fusion. > A fusion reactor doesn't require any form of mining for it's fuel. Thorium is incredibly common. Its already a waste in rare earth mining, so likely you wouldn't even need a single new mine. Every country has enough thorium in the ground to power itself. > A fusion reactor cannot meltdown in any way. Neither can a properly designed fission reactor. And in a molten salt reactor all dangerous gases are chemically bound in the salt and if removed from the reactor would freeze instantly not realising them into the air. A fusion reactor is actually more likely to release dangerous gases into the air. > Due to these inherent safety features, the costs associated with the regulation and engineering a fusion power plant could be much lower than a fission plant. That's a nice fantsay to have as we don't yet have fusion reactors so one can just make assertion. But as I explained above, a fusion reactor would need at least as much or more regulation as the fission reactors I describe above. And if you follow the industry you will know that those reactors have a very hard time clearing the regulation.

gizmondo 6y ago

It will be easy to use neutrons from DT fusion to get weapon-grade plutonium. This may be easier to police, i.e. "there should be no uranium nowhere near a fusion plant", but that's a much subtler statement. And of course mining for lithium as a fuel is still necessary, so you should perhaps say "no additional mining" or something.

willis936 6y ago
The need for lithium is a valid point. The amount required for fuel is very small though. A 1 GW plant would use more on initial filling than a 30 year lifetime of refilling and even that first filling would be on the order of a metric ton (unverified ballpark, dependent on reactor size, blanket thickness, and plumbing overhead). 80,000 metric tons of lithium are mined each year. We consume about 18 TW. So I estimate that converting all electricity sources to fusion would use about 1/4 of a year’s worth of lithium, but would be enough to make 30 year plants, which would still have most of their lithium left over for recycling/reuse afterwards.
pfdietz 6y ago
And enriching lithium is necessary. A single ARC reactor would use a good fraction of all the 6Li produced for the US thermonuclear weapons program. The tritium produced in a fusion reactor program would make it much easier to engineer high yield fission bombs, via boosting.
rnhmjoj 6y ago
> And of course mining for lithium as a fuel is still necessary, so you should perhaps say "no additional mining" or something. True, but the quantity of lithium required to breed tritium for power generation is ridiculously low. Operating a DEMO-like reactor for 30 years would consume 2 tons of lithium, which is nothing compared to the annual consumption for battery manufacturing (around 30000 tons).
- pfdietz 6y ago
  The blanket of DEMO, if using PbLi eutectic, would require 52 tonnes of 6Li. In addition to the raw lithium itself, building even a single reactor like DEMO would require maturing a new 6Li separation technology (the old one caused unacceptable mercury pollution) and industrializing it. https://www.sciencedirect.com/science/article/pii/S092037961930835X https://www.sciencedirect.com/science/article/pii/S092037961...
nickik 6y ago
You can not actually police that sort of thing. Thorium is literally everywhere in the earth core. You could basically dig hole right next to your fusion reactor and mine Thorium right out of it, expose it to neutrons and create Uranium-233.

bruckie 6y ago

I suspect a reactor that uses FLiBe can produce pollution: the BeF2 in the solution is toxic, and presumably would have to be replaced periodically. https://en.wikipedia.org/wiki/Beryllium_fluoride#Safety https://en.wikipedia.org/wiki/Beryllium_fluoride#Safety

pfdietz 6y ago
If the Be is not recycled then Be consumption becomes unacceptable. A single ARC reactor (2014 paper) would use 40% of the world's annual production of the element.

nickik 6y ago

> A fusion reactor doesn't create create long-lived radioactive waste (or any kind of pollution). It can create things that take 100 years, a closed cycle thorium breeder takes 200-300 years. And the waste from that process is actually quite useful to extract isotopes for medical, nuclear batteries and other applications. > A fusion reactor cannot be used to create nuclear weapons. That is just flat wrong. Most fusion reactors that are considered today absolutely can be used to create nuclear weapons. I would argue starting a nuclear weapons program if you have control over a fusion reactor is far easier compared to when you have a thorium breeder. While it is possible in theory, in practice nobody would ever do it. Your whole workforce would suffer from to much radiation and because of certain other parts of the material, it would be incredibly easy to track in terms of proliferation. This is a buggy-men, and would still be with fusion. > A fusion reactor doesn't require any form of mining for it's fuel. Thorium is incredibly common. Its already a waste in rare earth mining, so likely you wouldn't even need a single new mine. Every country has enough thorium in the ground to power itself. > A fusion reactor cannot meltdown in any way. Neither can a properly designed fission reactor. And in a molten salt reactor all dangerous gases are chemically bound in the salt and if removed from the reactor would freeze instantly not realising them into the air. A fusion reactor is actually more likely to release dangerous gases into the air. > Due to these inherent safety features, the costs associated with the regulation and engineering a fusion power plant could be much lower than a fission plant. That's a nice fantsay to have as we don't yet have fusion reactors so one can just make assertion. But as I explained above, a fusion reactor would need at least as much or more regulation as the fission reactors I describe above. And if you follow the industry you will know that those reactors have a very hard time clearing the regulation.