Slashdot Mirror
Could a Helium-Resistant Material Usher In an Age of Nuclear Fusion? (sciencealert.com)
Researchers working with a team at the Los Alamos National Lab tested a new way to build material for nuclear fusion reactors, "and found that it could eliminate one of the obstacles preventing humanity from harnessing the power of fusion energy." schwit1 quotes Science Alert:
A collaboration of engineers and researchers has found a way to prevent helium, a byproduct of the fusion reaction, from weakening nuclear fusion reactors. The secret is in building the reactors using nanocomposite solids that create channels through which the helium can escape... Not only does the fusion process expose reactors to extreme pressure and temperatures, helium -- the byproduct of fusion between hydrogen atoms -- adds to the strain placed on reactors by bubbling out into the materials and eventually weakening them...
In a study published in the journal Science Advances, the researchers overview how they tested the behavior of helium in nanocomposite solids, materials made from thick metal layer stacks. They found that the helium didn't form bubbles in these nanocomposite solids like it did in traditionally used materials. Instead, it formed long, vein-like tunnels. "We were blown away by what we saw," said Demkowicz. "As you put more and more helium inside these nanocomposites, rather than destroying the material, the veins actually start to interconnect, resulting in kind of a vascular system."
The article points out that nuclear fusion generates four times the energy of nuclear fission.
In a study published in the journal Science Advances, the researchers overview how they tested the behavior of helium in nanocomposite solids, materials made from thick metal layer stacks. They found that the helium didn't form bubbles in these nanocomposite solids like it did in traditionally used materials. Instead, it formed long, vein-like tunnels. "We were blown away by what we saw," said Demkowicz. "As you put more and more helium inside these nanocomposites, rather than destroying the material, the veins actually start to interconnect, resulting in kind of a vascular system."
The article points out that nuclear fusion generates four times the energy of nuclear fission.
I’m been hearing fusion is only 20 years away for at least 30 years now.
It is worse than that. The time until we get fusion power is a monotonically increasing function of calendar year. In the early 1950s, when Project Sherwood was started, it was highly classified because it was thought that it would produce fusion power so soon (i.e. less than a decade) that it would be a valuable military technology. By the late 1960s they were talking about it being achieved in 20 years. By 2000 the timeline had grown to 30+ years.
In 2014 the projection for DEMO, the ITER follow-on, which is described as a system that would bring us to the "threshold of a prototype fusion reactor", i.e. short of being an actual prototype fusion power reactor, which in turn is short of being an actual commercial power reactor, was projected to start operating in the 2040s, i.e. at least 30 years, if no further schedule slippages occur. Currently, PROTO, the actual prototype fusion power reactor is not envisioned before the 2050s and likely later, which brings us about 40 years, and we still aren't talking about an actual commercial power plant. Allowing for the established 20 year cycle for each iteration of a major fusion reactor project, we might get that commercial power plant in 60 years. But it will be too expensive to compete with other sources of power.
Is some other new fusion design going suddenly break us out of this pattern? There is no law of nature against it, so it is possible. But literally hundreds of fusion schemes have been investigated, and without exception every concept has proven much harder in practice than on paper (or computer). Engineering by press release does not cut it (Lockheed Martin I am looking at you), until an actual demonstration unit is operating with predicted performance all claims on new breakthroughs should be ignored.
Starships were meant to fly, Hands up and touch the sky - Nicky Minaj
> and insurmountably too expensive due to physics
It already has, and everyone knows it. It's not just fusion, it's fission too. If you have neutrons in the first loop, you are uneconomical. Period.
The cost of a modern fission reactor is around $10/Wp. Of that, about $6/Wp is the generation loop. Only about $1 to $1.50 is the actual reactor itself.
So in other words, the lowest possible price you can build a [fission|fusion] plant for is about $6/Wp. And that's without the reactor.
A wind turbine that produces the same amount of power costs about $1.25/Wp. Because the wind doesn't always blow, to make the same amount of energy you need three of them. So a generator using wind turbines that produce NNN power will cost you about $4.50 complete, whereas for $6 you still only have a cooling loop on your nuclear plant.
The power companies have been telling the labs they won't build these things since the beginning. The Stellarator D study in 1958 produced a machine that was 500 feet across and twisted like a pretzel. The power company liaisons working on the report told them there was absolutely no way anyone would ever build such a thing. The physicists basically said "who cares" and went back to their physics, saying that since the physics didn't work then the study was dumb anyway.
That pattern repeated itself dozens of times over the next 30 years. Every so often someone would think they were getting close to a working design, and they would do a commercial design effort. And every time, the power companies would tell them in no uncertain terms they were smoking pure hopium. GE threw in the towel in 1965 when they did their own study that said the same thing. The largest one I know of is the Bechel report from ~1975, and once again the same outcome - no way anyone would ever build one.
Everyone in the field is aware of this. It's gotten to the point that if you bring this up they either yell at you (literally, had this happen to me) or do the equivalent of "LA LA LA I CANNOT HEAR YOU!". It's astonishing to watch.
Yeah, it would be great if we had such a thing, but keep in mind the criteria a replacement has to meet. You need materials that can handle the sheer magnitude of heat energy of these plants. You need materials that will fail in the safest way possible. You need to be able to afford said materials. And that's assuming competency and responsibility all around.
The buzzword pop-sci solution would probably be some kind of metamaterial that can convert heat into electricity. or something harvested with greater efficiency. But even if such a material were created, it would have to be competing with water.
This is my signature. There are many like it, but this one is mine.
Before you start worrying about the walls of your fusion machine, you need a fusion machine that can provide net positive energy.
Excuse me, but the point of this article is that the walls are part of the fusion machine.
When all you have is a hammer, every problem starts to look like a thumb.
Oh god not this chart again. Anyone that posts this is demonstrating that they are unfamiliar with the history and physics of fusion. So let's explore this...
Right when the entire concept was starting in the 1940s, there was a theoretical calculation that estimated how quickly the plasma would leak out of the machines. Among the various inputs were two that were key - the plasma leaked slower out of larger machines because it had further to go, so that was linear with size, and in addition, the scattering varied with the square of the magnetic field strength so if you made the magnets even a little stronger then you're good to go.
However, there was one problem. During the war, they had actually worked with magnetically confined plasmas as part of the bomb project. The actual measured results from these experiments were WAY faster than what the classical math predicted. Most worryingly, the magnetic field only improved the times linearly. If this "Bohm diffusion" was correct, there was no hope of making a working reactor.
So when they built the first machines and ran the calculations, it appeared the classical numbers were working. If they just made it bigger they would be off to the races. So through the late 1950s and into the 60s they did that. And sure enough, the results got worse. At a 1968 meeting, Spitzer, the dean of the US program, had a chart showing that the entire stellarator series was clearly following the Bohm model.
Fusion was dead.
Funny thing though... at that same meeting the Soviets showed the results of their new tokamaks and they were 10x Bohm. The results were so good, no one believed them. They had to invite a team from the UK to use their laser scattering probe before anyone was convinced it actually worked.
And then there was a sudden rush to build tokamaks. So much of a rush that they converted the biggest stellarator into one and never looked back. Now the problem was not stability, it was heating the fuel - previous machines like the pinch series heated the fuel by either compressing it rapidly or running a current through it. The tokamak showed that there were hard limits on both, and these were too low to use for heating.
So through the 1970s you had a series of experiments all around the world on how to heat the fuel. Generally, the US was the winner. The PPPL's PLT machine was able to hold its plasma and heat it until it reached the conditions for fusion. All that was left was to increase the pressure to a useful figure, and then introduce tritium so the thing would actually burn.
And that's where this graph comes in. Notice the start point of this graph, in the mid-1970s. This is when Hirsch was putting together the Manhattan Project-level attempt to make a working commercial machine around 2000. Based on this there were going to be three machines in a rapid sequence, first the follow-on to the PLT, which became TFTR, then a prototype generator that also handled tritium production, and then the prototype commercial machine. That's the green line in the chart.
What actually happened is that they built TFTR and it didn't work. As they ramped up the dials, the machine became increasingly unstable. By around 1983 TFTR failed, MFTF never even turned on, and congress, realizing no one really knew what the hell was going on, cut the funding.
So basically the green line is based on the underlying premise that they actually understood the physics. But they didn't. And if you don't understand the physics, it doesn't matter how much money you pour into it, it still won't work. So the black line happened.
In spite of this, fusion proponents keep putting this up and blaming money for "the problem". THIS IS A PHYSICS PROBLEM, IT'S NOT A MONEY PROBLEM. And we still don't really know the solution, and a trillion dollars won't fix that.
I think Maury may have some background in fusion research. If not, I do, at least.
The problem is not just money. It's also what the money is being used for: what kind of reactors are being built, what metrics are the government program managers are being sold on, what kinds of scientists are you employing, etc. There is a very big distinction between trying to solve engineering problems and physics problems.
ITER, and other reactor designs solve engineering problems, and try to answer the question "can we build a reactor with these specific plasma properties?" The physics questions are a lot more open ended, and any physics project has a much higher chance of failure than an engineering project.
I said I have some background in fusion. I worked on DIII-D which is a large fusion reactor run by General Atomics. Back then, I was probably best described as a computational physicist, now I'm a condensed matter physicist. I got into condensed matter physics because of my work on DIII-D. There were a lot of fusion scientists about 30 years ago who argued strenuously against building bigger and more expensive reactors. Instead, they argued we needed to focus on developing better components for the reactor designs we already have. That idea became IFMIF - a facility to test materials for fusion reactor use (fusion science likes these monolithic large projects - easier to fund, but they are SLOW). ITER was made the funding and marketing priority over IFMIF. Now, we're into engineering design on the system after ITER (DEMO), which requires input from IFMIF... which is still not built. So once again, we will go build an incredibly expensive reactor while using materials we know will not work in a commercial system because we're not willing to prioritize solving the physics problems. So, we can go on like this building reactors for a very long time without making real progress, and spend a lot of money along the way.
This Helium bubble stuff is interesting, but it's not a driving consideration. This is the kind of small project they've thrown to the materials folks to keep enough people involved until IFMIF is built.