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New records on Wendelstein 7-X

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Re: New records on Wendelstein 7-X

#51
TL;DR - Looks dangerous, but is it? (open question) Can we quantify it or at least make it more tangible?

God, this contraption appears to be the kind of thing I wouldn’t trust my life with. Every time I look at a fusion reactor, it seems far more dangerous than my hobby lab, failing to inspire any confidence. The numerous moving parts create an equal number of potential points of failure. In contrast, a nuclear reactor doesn’t have to contend with plasma gases hotter than the Sun, contained within an artificial bubble solely through the assistance of electromagnetic radiation.

I’ve often tried to imagine the worst case scenario, but I am limited by my knowledge on the subject. What kind of damage can hot plasma at a few million degree C do?

On one hand, the plasma is hotter than anything on earth created by mankind. Then I believe there’s also a significant number of wild neutrons shooting around which can cause havoc in their own right, if not contained. But on the other hand, unlike an uncontrolled chain reaction, without a source of heat, the whole operation shuts off by itself. I’m probably wrong about a few assumptions here but this is what I often find myself wondering.

Re: New records on Wendelstein 7-X

#52

Earlier quoted context omitted.

I'd say (older-generation) fission is more like having an indoor swimming pool filled with burning gasoline, but keeping the windows shut so there's only enough air for it to burn at the rate you want to heat the house.

Or a swimming pool full of those spicy rocket propellents discussed in the book Ignition! which have combustion products like hydrogen fluoride.

"Things I will not work with" - "at this point hydrogen fluoride loses its gentle nature".

Re: New records on Wendelstein 7-X

#53

Looking at the picture, I wonder if complexity of these devices will significantly be reduced once it finally works. I assume a lot of the bells and whistles are needed to find the way, but once it's found..

Your question reminds me of the image showing how SpaceX raptor motors evolved https://imgur.com/a/4w3q3lS

Wow - beautiful. So there is hope! As someone unfamiliar with the challenges of mechanical engineering, I’ve often wondered at the complexity of fusion reactors. This picture puts a lot into perspective. Thanks for sharing!

Re: New records on Wendelstein 7-X

#54

I've always been somewhat partial to the stellarator design, I mean a big plasma donut is cool and all, but what if we twisted it around a whole bunch first!?

I think gravitational confinement is the way to go - it's the only operationally proven design! Gotta think big!

You only need one at that point!

Re: New records on Wendelstein 7-X

#55

TL;DR - Looks dangerous, but is it? (open question) Can we quantify it or at least make it more tangible? God, this contraption appears to be the kind of thing I wouldn’t trust my life with. Every time I look at a fusion reactor, it seems far more dangerous than my hobby lab, failing to inspire any confidence. The numerous moving parts create an equal number of potential points of failure. In contrast, a nuclear reac…

I'd imagine that these research reactors are chock full of "adjustable parameter" parts and modular assemblies.

Once they get everything dialed in, they can make a static purpose built machine with dramatically less complexity. Generally with research machines they are very unwieldy while still being dialed in.

Re: New records on Wendelstein 7-X

#56

Earlier quoted context omitted.

I'd say (older-generation) fission is more like having an indoor swimming pool filled with burning gasoline, but keeping the windows shut so there's only enough air for it to burn at the rate you want to heat the house.

Or a swimming pool full of those spicy rocket propellents discussed in the book Ignition! which have combustion products like hydrogen fluoride.

Would love to take a look at your library.

Re: New records on Wendelstein 7-X

#57

Earlier quoted context omitted.

I'd say (older-generation) fission is more like having an indoor swimming pool filled with burning gasoline, but keeping the windows shut so there's only enough air for it to burn at the rate you want to heat the house.

Or a swimming pool full of those spicy rocket propellents discussed in the book Ignition! which have combustion products like hydrogen fluoride.

Neither of the hypergolics described in Command and Control seem chill either: the fuel reacts with atmospheric water and oxygen, the oxidizer is in the highest category of poison (https://www.penguinrandomhouse.co.za/extracts/command-and-co...).

Indeed there's no such thing as a free launch, and that is rocket science.

Re: New records on Wendelstein 7-X

#58
post #43
post #26

This article has zero quantifiable information in it aside from the duration... which has no context. Who's recordkeeping this stuff? What are the other results so far? What is the tipping point where it is net positive? how long does it need to sustain a net positive fusion reaction to produce sufficient power for grid consumption? Are there other losses (thermal generation inefficiencies) that make the target even…

Here is an actual article with some context - and a reality check that other experimental reactors in the past have sustained similar triple product for longer durations... https://www.ipp.mpg.de/5532945/w7x

>The fact that W7-X results are on a par with JET is remarkable because JET had three times the plasma volume of Wendelstein 7-X.

What's important here is that W 7-X is a stellarator, a different type of fusion reactor from almost all prior reactors (they are tokamaks), with a smaller volume than the co-record holder.

That a stellarator gets these results with a much smaller fusion volume is promising for the performance of future larger stellarators, since fusion reactors typically become more efficient as they get larger.

Re: New records on Wendelstein 7-X

#59

I've always been somewhat partial to the stellarator design, I mean a big plasma donut is cool and all, but what if we twisted it around a whole bunch first!?

I think gravitational confinement is the way to go - it's the only operationally proven design! Gotta think big!

It has density issues though. If you had a piece of the sun the size of a huge power plant - like enormous, the power output would be too low to be useful.

Re: New records on Wendelstein 7-X

#60
post #43

Earlier quoted context omitted.

Here is an actual article with some context - and a reality check that other experimental reactors in the past have sustained similar triple product for longer durations... https://www.ipp.mpg.de/5532945/w7x

>The fact that W7-X results are on a par with JET is remarkable because JET had three times the plasma volume of Wendelstein 7-X. What's important here is that W 7-X is a stellarator , a different type of fusion reactor from almost all prior reactors (they are tokamaks), with a smaller volume than the co-record holder. That a stellarator gets these results with a much smaller fusion volume is promising for the perfor…

All good information, entirely missing from the original article -
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