Successful second round of fusion experiments with Wendelstein 7-X

Now, it is true that there's still fundamental research to be done until energy production via nuclear fusion becomes a reality, but we're reasonably confident that we could make the conventional approaches work.

However, that research is Big Science, and there's no political will to fund it properly (the graph that people like to cite is https://commons.wikimedia.org/wiki/File:U.S._historical_fusi... ). ITER suffered from this as well, and W7-X basically only exists because German reunification happened, and the German government was looking for a big science project - any project - they could leverage to funnel money into East Germany. The plans for W7-X just happened to be ready at the right time.

In the US alone, oil subsidies are >$400bn a year.

Here’s an article - about the same amount, annualised, is spent on Halloween costumes for pets.

http://www.fusionenergyleague.org/index.php/blog/article/hav...

Some other numbers for comparison:

NASA's current ANNUAL budget is $19B. [1] The BP oil spill cost $40B. [2] "A 2016 IMF study estimated that global fossil fuel subsidies were $5.3 trillion in 2015, which represents 6.5% of global GDP." [3] The US alone spent $600B on fossil fuel subsidies in 2015. [3]

>It's not obvious that throwing more money at the problem is going to change this.

This is true, but we haven't funded it enough. The potential upside is insane. We aren't funding research accordingly.

[1] https://www.quora.com/How-much-money-is-being-spent-on-resea...

[2] http://www.fusionenergyleague.org/index.php/blog/article/hav...

[3] https://en.wikipedia.org/wiki/Energy_subsidies

That's not very long. The first liquid-fueled rocket was in 1914, and the moon landing wasn't until 1969, and even that was only possible with very high levels of funding far beyond what's invested in fusion power today. Babbage built the Difference Engine in 1822 and conceived of the Analytic Engine in 1837, leaving skeptics dismissing the potential of computers for 150 years. Leonardo da Vinci sketched a helicopter in 1480, almost 500 years before one could actually be constructed. Gunpowder was invented probably before the year 1000 and took over 700 years after that to render pikes obsolete.

Now, it's entirely possible that there's some other limitation holding us back from fusion, just as the lack of internal combustion engines or diodes held us back from helicopters or computers. But I think we've done enough work so far that we'd be able to tell if we were running into something like that. As it stands, I think we're roughly in the place rocketry was before WWII--we have an idea of how to do it, and we don't know if it'll go to the Moon or not, but the only way to find out for sure is to try, and that's pretty expensive and might take awhile.

We'd gladly be working on fusion (or other physics stuff) but our present jobs pay much better.

More money, and better pay for hard science careers, actually would make a difference.

Possible, but unlikely (imo). It's just that private business doesn't really do large-scale multi-decade pure research efforts with far-off ROI, and governments have chosen to spend money elsewhere. Hence, progress is steady, but slow.

The conversation came up because I was trying to fathom why a company would sit on billions of dollars when they could make more billions with it. This idea, that the future will have sudden insights that will take tremendous capital to exploit to create unassailable leadership positions, is not one I had considered. Fusion power, space opportunities, Etc, might be areas where things suddenly create an entirely new need.

It was just an enormous challenge to build this thing. Things like building and validating the field coils required a lot of effort and some novel approaches that they had to come up with along the way.

Fusion would be similar.

I think it's also possible that technological process happens in fits and starts instead of at a continuous or even a continuously changing rate. Often there's an individual discovery that leads to a spurt of innovation that consists mostly of applying that singular discovery to different problems.

For example:

* The late 19th and early 20th century saw very fast innovation in vaccines and antibiotics, because the discovery of effective vaccines and antibiotics was general enough to solve entire classes of problems all at once. It seems like a lot of innovations all at once when you manage to find extremely effective treatments against polio, smallpox, measles, syphilis, chlamydia, typhus, typhoid, tuberculosis, etc., etc., etc., but really that was just from a couple of extremely general inventions playing themselves out.

* Steam engines led to large-scale mechanization while electrical power led to small-scale mechanization in two relatively fast and concentrated chunks. In both cases, the invention of a general technique for powering machines led to lots and lots and lots of machines.

* Marconi's wireless telegraph was invented in 1896, leading to different varieties of radio, television, and radar.

* Airplanes might be another example. I don't want to dismiss the huge difference between a Wright Flyer and a Boeing 737, but "make the airplane out of aluminum" and "have a tube that the crew and passengers can be inside of" are both pretty obvious improvements once you've figured out large-scale manufacturing and the Bayer process, both of which we had ahead of time. I guess jet engines were another breakthrough, although we kind of had them already and they're basically just rockets except they consume oxidizer from the air instead of carrying their own.

* Rockets. There were less than three decades between the V-2 and the moon because it turns out "building a big rocket" is the hard part. OK, there are a lot of other hard parts to landing on the moon, but they're hard in the way that they're achievable by any sufficiently well-funded and motivated group of people with rockets, but nearly impossible without rockets. As you point out, Falcon 9 is significantly more advanced in certain ways than Saturn V, but the low-hanging fruit was reaped by Werner von Braun.

* Computers: just like the Saturn V is basically a very, very, very large V-2 and so is the Falcon 9, we're basically using very, very, very large (logically large; physically small) versions of the computers we had in the 1970's. The fundamental discoveries in computing are all basically done; the rest is just playing itself out. The reason it seemed to take longer to play itself out is because computers are a self-compounding invention: you can use computers to design computers, and you can use better computers to design better computers. Also, having computers makes a lot of other things easier, so you get a lot of innovation from that, too.

Fusion, promisingly enough, also seems to be one of those technologies that will just unlock a bunch of really, really powerful innovations, seemingly all at once, because of how many problems we could solve by just throwing lots and lots and lots of energy at them. (Some discussion here: https://www.youtube.com/watch?v=8Pmgr6FtYcY . Also, the excellent book "Sustainable Energy - without the hot air" develops rough upper bounds on the amount of sustainable energy that the UK could produce and the amount of energy the UK consumes, ultimately leading to the bar graph Figure 18.1 here: https://www.withouthotair.com/c18/page_103.shtml. Later discussion of nuclear fusion places the same bar graph, to scale, next to the sustainable level of fusion power production on Figure 24.17 here: https://www.withouthotair.com/c24/page_173.shtml.)

It wasn't the computational revolution that made SpaceX possible, the basic technology is more or less the same as it was in the 60s. The Merlin engine has it's roots in the '90s NASA Fastrac design, evolved for performance and reusability.

SpaceX's success relates to things like market incentives, lean business practices, a fail early and iterate quickly attitude as opposed to "too big to fail" public projects, and so on.

The issue is the design of extremely specialized components, not necessarily the raw materials (except when they're novel superconducting magnets designed for that purpose).

I think schedule delays are what is making ITER so expensive.

Not necessarily, because discovering a large blocker would give us an idea of what to invest in next.

The economic impact of fusion power is great enough that even if there's a 10-25% probability of it working out, the expected value implied by that probability would justify significantly higher levels of funding than fusion currently receives.

> It’s not like fusion isn’t being actively investigated and invested in. It is, to the tune of tens of billions of dollars. How about we see how those projects pan out in practice and then progress from there?

ITER, the largest multinational fusion project, is projected to have a total cost of over 20 billion euros, which is about 22 billion USD. 22 billion USD is less than NASA's budget, adjusted for inflation, for the single years of 1963 through 1970 or 1990 through 1993. And NASA's work is built on top of the rocketry work of Nazi Germany, which cost about 40 billion inflation-adjusted dollars even with, to be euphemistic, artificially low labor costs.

For another point of comparison, the Persian Gulf War, which was primarily motivated by the attempt to secure part of the global supply of petroleum, cost $61 billion. The Iraq War cost at least an order of magnitude more, but (a) many of that was due to cost overruns and (b) that war was partially motivated by issues other than securing part of the world's petroleum supply.

In terms of improving long term human living conditions and enabling future economic growth, developing fusion power would provide tremendous benefits.

nothing is simple, nothing is elegant. Everything is hideously complex, we are just standing on the shoulders of giants. e.g. Try making common things that we take for granted, like building a plane or glider or even writing a text editor from scratch (including the font rasterization code and display driver).

No, it doesn't.

> Conceptually fusion seems pretty simple: why in principle does harnessing it require super-human complexity?

Because having 2e30 kg ball of hydrogen within a powerplant is extremely unwieldy here on Earth.

> In software, if you are replacing divisions with bit shifts, maybe you really need a different algorithm.

Huh? If your algorithm says "divide by 4", why would you need a different algorithm.

All your useful materials melt at 2000 degrees.

The fusion takes place at 20000000 degrees.

Mystery solved.

(Yes I know these numbers are grossly oversimplified.)

A design that produces e.g. 2x the energy it consumes for the startup could be viable, even if pulsed (running minutes, not months).

If this is economically infeasible, then again, building piecemeal may be better, in the same way as taking a credit and paying interest on it might be better if you can't secure the upfront sum anyway.

In practice, coing down to ~40 C (~100F) is not uncommon. And then the waste heat is basically unusable, even for district heating.

OTOH, if you need lots of heat (maybe you have a chemical plant or something nearby), you can design you powerplant for cogeneration of heat and power, yielding higher total system efficiency. But you don't do that "just" for district heating.

SCNR. Seriously though, molten salts are great heat transfer media, a bit like water, just at higher temperature and still low pressure. They are also completely immune to radiation damage, which is a big deal if you have 14MeV neutrons flying around and something has to stop them. Chemistry in molten salts is also interesting. Things can be extracted (say, into a molten metal phase) or precipitated, and some reactions just happen at 600 degrees while they need platinum and palladium catalysts at room temperature. What's not to love?

In a molten salt reactor, there is very little volatile material inside the containment building. The salt itself does not have high vapor pressure, even in accident conditions. As a result, the size (and cost) of the containment building can be radically reduced. Moltex's design, for example, reduces the cost (per unit of power output) of the containment building by a factor of 5 vs. LWRs.

Producers of wind and solar power would love to hear about them!

Re SPOF: since the fusion devices are much less reliable, as of now, than reservoirs of hot liquids, I suppose the reservoir is much less of a concern.

I understand that fusion efficiency grows with size; this is why we are surrounded with colossal self-initiated fusion reactions, and have one nearby! But before we can scale, maybe we could still turn net-positive with smaller, less reliable devices. Remember how unreliable first cars were.

This is not just quibbling, since bad power density is a huge problem with fusion.

Look at ITER. The volumetric power density (gross fusion power/volume of reactor proper, not including the building or auxiliary equipment) is 0.05 MW/m^3. Compare that to a PWR primary reactor vessel, which have a power density around 20 MW/m^3. The smaller designs like ARC or Lockheed's concept have power density around 0.5 MW/m^3.

No idea if a neutron flux picture would provide these details or not.

[0] https://www.ipp.mpg.de/4550362/original-1543230147.jpg?t=eyJ...

I think you have to go to quite low energies (per neutron, not flux) for neutron optics to be a thing. Neutron cameras use collimated neutron sources to get around this, but that option isn’t available here: https://en.m.wikipedia.org/wiki/Neutron_imaging#Neutron_came...

Wait, so does this mean that you have a camera obsucra with an array of optical fibres at its back, and then you have an ordinary CCD camera imaging the other end of the fibre array?!?!

As a side note, you gotta love HN... where you ask a question about some obscure thing and often get an answer straight from the source.

There's a real physical ceiling to how much power can be consumed on Earth's surface, regardless of its source.

The first and primary goal of ITER is to show that the disruption problem can be and has been solved. If they don't do this, ITER will never be allowed to operate with a DT plasma. And they are still scrambling to solve the problem.

Zach Hartwig of MIT has an excellent video [0] of how to evaluate announcements of nuclear fusion advances. The big problem is breaking even. There are other problem, too: plasma containment, etc.

[0] https://www.youtube.com/watch?v=L0KuAx1COEk