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Comment by leonidasrup | Hacker News Reader

For those interested not only in simplified energy balance of a fusion power plant as shown in Fusion Power Plant Simulator, but in more realistic engineering of heat extraction from a tokamak I recommend the following lecture by Dr. Dennis Whyte from MIT Plasma Science & Fusion Center.

Fusion Reactor First Wall Cooling

https://www.youtube.com/watch?v=bHJyoqDO0zw

One of the designs uses 3D printed silicon carbide vacuum vessel cooled by a layer of molten lead and a layer of FLiBe (a molten salt made from a mixture of lithium fluoride (LiF) and beryllium fluoride (BeF2)).

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

The lithium component of FLiBe is used for breeding of the radioactive isotope tritium, which will be extracted from the salt and used for making the deuterium-tritium fuel of the tokamak.

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My favorite video that walks through fusion energy design/sizing/cost equations is also a lecture by Dennis Whyte: https://youtu.be/KkpqA8yG9T4?si=U8xaAAvjdnt6yqr8 It’s a really engaging lecture - I’m normally pretty put off by 100-minute lectures on YouTube but this one was both very easy to follow and perfectly scoped. Can highly recommend it - the learnings from it are timeless fundamentals that really make fusion power design and economics accessible.

The big takeaway is that better magnets reduce reactor size by the 4th power, and energy output and cost by the cubed power. Finding a material for the magnets which doubles their strength would reduce the size of the reactor by 94% and the cost by 88%.

A possible conclusion one could make is that with regular advancements in magnets it’s very possible that the first operational commercial fusion reactors will be relatively low-cost compared to current and planned fusion reactors, and even though they may begin construction after the next generation of super-sized fusion reactors - they might be finished and operational before their “predecessors” with inferior magnets have completed being built.

Some Sci Fi authors have made the point that the first interstellar space ship is likely to be greeted at their destination star by human immigration control officers boggling at their long superseded sublight ship.

This is also one of the reasons ITER is such as bad project. It's so big, slow, and had to be planned so far ahead that it "locked in" older superconducting tape technology that has been superseded.

The wildcard for our civilization that I pay a lot of attention to:

will AI help us get through blockers like this?

I'm out of the prediction business but my guess is: absolutely, but iff we don't collapse in some way first.

Wild to be alive as the centuries-long horse race of industrialization between doom, or the stars, approaches its finish line.

How would AI help achieve commercial fusion? You first need to identify the blockers. These almost all entirely boil down to "how do we precision machine large pieces of hard metal?", "how do we assemble facilities with untold process channels?", "how do we capture neutrons without making a prohibitively massive machine?", and "how do we make metal that doesn't melt?".

Now, AI might have a chance at supercharging material research and making miracle materials that help address the blanket and first wall challenges, but honestly those are roadblocks we're not even running into yet. AI can not and will not fix issues related to organizing labor and supply chains and suddenly make megaprojects have a 100% success rate for on-time and on-budget. It's just not going to happen.

So are these problems intractable? Of course not. It's just not what the chatbot is well suited for. Anyone saying otherwise is selling something.

This is the science fiction fan's version of hopes and prayers.

Fwiw, machine learning is already being used for plasma simulations.

The race between doom and the stars is something I think about quite a bit.

>realistic engineering of heat extraction from a tokamak

This is why I love the idea of Helion so much.

Who knows if it will ever work, but skipping the thermal transport and doing direct current generation from EMF in the reactor seems like it has tremendous potential for simplifying (and eventually downsizing)

It would be quite outstanding if MIT Plasma Science & Fusion Center released their core courses on OpenCourseWare. Considering the potential impact of this technology and how much it's needed, humanity doesn't seem to be trying that hard to make it work.

> cooled by a layer of molten lead

Really gives a perspective on the range of temperatures handled.

Completely random fun fact, the word "flibe" means "spittle" / "drool" in (west) Frisian (https://en.wikipedia.org/wiki/West_Frisian_languages).

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