I found this panorama shot on their home page: https://www2.ipp.mpg.de/ippcms/eng/externe_daten_en/panorama...
Successful second round of fusion experiments with Wendelstein 7-X
181–190 of 223 posts
Re: Successful second round of fusion experiments with Wendelstein 7-X
#182Earlier quoted context omitted.
I agree. I hear the comments about a lack of funding but to me it isn't necessarily a lack of vision from politicians and businessmen. I have a Ph.D. in physics and even worked for 6 months full-time in the Princeton Plasma Physics Lab as an undergraduate and I still hav mixed feelings about fusion power, particular vs other non-fossil fuel options.
Among other things, there's a perception of fusion as this clean, infinite energy source. I haven't followed fusion carefully for a good many years but back when I was studying material science, radiation embrittlement of fusion reactor shielding was an area of active research. It wasn't clear that you didn't end up with just as much radioactive waste from fusion as you did with fission. Don't know what the current t…
Sure, we might, but the "issue" of management of macro-scale solid radioactive waste has never been anything but nonsense. It is a completely manufactured "problem." Mix it with concrete and cast it into large bricks so that it's hard to lose and infeasible to steal, vacuum seal it in plastic wrap as a precaution against outgassing, drive it to the seaside in lead lined semi trucks and toss it off the continental shelf.
Re: Successful second round of fusion experiments with Wendelstein 7-X
#183If this ends up being the right design for fusion, it may be the most weirdly shaped human artifact, where the shape is fundamental to its operation and not decorative. It's far more complex than a mere turbine blade or venturi. Or can anyone suggest a weirder one? (Define weirdness as the Kolmogorov complexity of the shape, within the precision needed to work properly.)
Does a CPU count? The functional part is a very precise, complex and intricate shape.
CPUs also have some iterative weirdness in that successive generations do, to a certain degree, depend upon the computation of the previous iteration to calculate the layout.
Re: Successful second round of fusion experiments with Wendelstein 7-X
#184Earlier quoted context omitted.
https://wikipedia.org/wiki/The_Feeling_of_Power asimov and manned-missiles
Good example. Now compare with Franchise , Jokester , All the Troubles of the World , The Last Question and many more stories that feature as a plot device a very powerful centralized computer named Multivac. (See https://en.wikipedia.org/wiki/Multivac for a more complete list.) How the same mind could have come up with the idea of androids with positron brains following the three laws of robotics, and yet missed poc…
Heinlein predicted electronic calculators shortly after WWII in Space Jockey. The space ship has a little calculator, while the big computer is on a space station. That's more or less in line with late 60s or early 70s tech. I think a lot of science fiction has predicted 20 years out pretty well. It's past that that it usually goes off the rails, only because of the inherent difficulty of predicting the future.
Re: Successful second round of fusion experiments with Wendelstein 7-X
#185Earlier quoted context omitted.
Err no, money is not "the only thing" keeping us from having fusion power. I can think of one other thing which is that it's damn hard to create stellar-core conditions inside of a small containment vessel on Earth. It's not obvious that throwing more money at the problem is going to change this. After all, fusion research has been funded in some form or another since the 1950s. I'll bet if you added up all the resea…
The total since research started is somewhere between $25bn and $50bn. 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...
Not to mention the total expenditure on fusion weapons.
Re: Successful second round of fusion experiments with Wendelstein 7-X
#186Earlier quoted context omitted.
Just for the record, you don't re-create stellar-core conditions with earth-bound fusion devices: We don't have the means, and the yield would suck. 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 poli…
>> 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 That's the first time I've heard that. Brilliant!
It's wrong, though.
Re: Successful second round of fusion experiments with Wendelstein 7-X
#187Earlier quoted context omitted.
If the Stellerator, or any of its descendants, turn out to be the answer to practical fusion, it would have been contingent on vast quantities of computational power being available cheaply. It does not matter how much money you poured into your Stellerator project in 1970, you could never have built the 7-X, because there would have been no way to produce that design in the first place. Personally, I think one of th…
An exact replica of Falcon 9 was impossible 40 years ago, of course. But a replica with 50% lower thrust, 10% lower ISP and 60% it's payload capacity for a similar inflation-adjusted price was certainly possible. 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…
Both you and I (and hopefully most of HN) know that fusion is safe. But I can't imagine the public perception being great if "fail early and iterate quickly" was attached to anything with "nuclear" in the name.
Re: Successful second round of fusion experiments with Wendelstein 7-X
#188Earlier quoted context omitted.
Among other things, there's a perception of fusion as this clean, infinite energy source. I haven't followed fusion carefully for a good many years but back when I was studying material science, radiation embrittlement of fusion reactor shielding was an area of active research. It wasn't clear that you didn't end up with just as much radioactive waste from fusion as you did with fission. Don't know what the current t…
Sure, we might, but the "issue" of management of macro-scale solid radioactive waste has never been anything but nonsense. It is a completely manufactured "problem." Mix it with concrete and cast it into large bricks so that it's hard to lose and infeasible to steal, vacuum seal it in plastic wrap as a precaution against outgassing, drive it to the seaside in lead lined semi trucks and toss it off the continental she…
That kind of thinking in the past has lead to toxic consumer fish close to where I live - can't remember if it's mercury or dioxin.
It is actually pretty hard to come up with a solution that's going to be safe for 1000 of years.
I might be wrong but I think all countries so far has opted for the solution of putting the stuff somewhere they can keep an eye on it, and possibly get it up again in case somebody figures out a use for it.
Re: Successful second round of fusion experiments with Wendelstein 7-X
#189Earlier quoted context omitted.
If the Stellerator, or any of its descendants, turn out to be the answer to practical fusion, it would have been contingent on vast quantities of computational power being available cheaply. It does not matter how much money you poured into your Stellerator project in 1970, you could never have built the 7-X, because there would have been no way to produce that design in the first place. Personally, I think one of th…
Uhh... are you aware that the 7-X design was computed in the late 80s? 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.
The GP's comment
> the stellerator design, in a deep and fundamental way, simply isn't possible without massive computational power, whereas we've been building tokamaks since before massive cheap computational power.
does not square with Wikipedia:
> Stellarator ... The first Model A started operation in 1953 ...
Re: Successful second round of fusion experiments with Wendelstein 7-X
#190> The result was high plasma densities of up to 2 x 1020 particles per cubic meter – values that are sufficient for a future power station. At the same time, the ions and electrons of the hydrogen plasma reached an impressive temperature of 20 million degrees Celsius. > Since the fusion fire only ignites at temperatures of over 100 million degrees, the fuel [...] Would it be accurate to say that this gets us 20% of t…
Unfortunately overly simplistic. The challenge with higher plasma temperatures is that the internal shielding needs to be better than the current graphite tiles. They will upgrade those next and go with more complicated water cooled carbon fiber strengthened carbon tiles.
Note that Wendelstein 7x will never operate to produce actual fission with DT fuel, because that is (a) outside its mission goal, which is to research plasma behaviour at conditions close to what is needed in a power plant and (b) dealing with the neutron bombarding creates all sorts of complexities in terms of the blanket. Not really solved here as well, as Wendelstein 7x is a nightmare to disassemble and upgrade. For a power plant maintenance and serviceability needs to be build into the design. And (c) they don't have the government permission to deal with nuclear material and nuclear waste.
So no, we are not 20% there. But we have proven that (a) the Stellarator actually has wings, and (b) plasma physics so far behaves mostly as predicted. Especially the latter is something to be celebrated, because plasma is nasty in terms of physical properties, really complex to model, etc.