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Successful second round of fusion experiments with Wendelstein 7-X

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Re: Successful second round of fusion experiments with Wendelstein 7-X

#31

Post by pastullo »

nine_k wrote: post #12

With fusion devices having trouble to confine the plasma for long times, I wonder if a massively-parallel fusion plant woud be feasible. Let's assume that plasma destabilisation does not damage the device, and is a mundane event. Build 10 or even 20 fusion devices (economy of scale!) feeding the common heat buffer, e.g. a large reservoir of a molten salt or metal. Feed conventional turbines off the heat of the heat t…

The idea of having many small fusion reactors is quite interesting. I never thought about it and i would normally dismiss it since building a big one is cheaper than building many little ones. However, SpaceX and their 9-engine Falcon rocket teach us a different story. Sometimes building smaller yet complicated power plants is cheaper than building fewer ones but bigger.

Would be great to know more about the economics behind a multi reactor power plant.

Re: Successful second round of fusion experiments with Wendelstein 7-X

#32

Post by Retric »

nine_k wrote: post #12

With fusion devices having trouble to confine the plasma for long times, I wonder if a massively-parallel fusion plant woud be feasible. Let's assume that plasma destabilisation does not damage the device, and is a mundane event. Build 10 or even 20 fusion devices (economy of scale!) feeding the common heat buffer, e.g. a large reservoir of a molten salt or metal. Feed conventional turbines off the heat of the heat t…

Ok, several issues with this. First restarting these devices takes a lot of electricity, which drastically reduces your net efficiency. So, you still really want to solve this problem.

Second, fusion devices scale very well so one device at 10x the scale is vastly better than 10 different devices at x size. Third, storing and pumping heat involves losses, where there is a huge range of great options for storing electricity. Fourth, it takes massive turbines to turn heat into energy, so you need to scale several things on both sides of your merged heat system in your modular design.

Finally, X independent fusion devices don't have single points of failures shared between them. Your combined design would.

Re: Successful second round of fusion experiments with Wendelstein 7-X

#33

Post by olau »

ttul wrote: post #3

Experiments like Wendelstein remind me that the only thing holding back fusion power is money for research like this. Every year, we spend billions on fossil fuel exploration because the return on investment is quick - just think about all the wells going in to extract shale oil. What if we collectively had the will to invest this much into fusion?

It sounds like you think fusion would be a great alternative source of energy since you're comparing it to fossil fuel exploration.

However, this is not necessarily true. It not only has to work, it also has to be economical and not have significant drawbacks.

I think that's very much up in the air. Compare it to fission - we know how to build those power plants, but it's just so damn hard that it's too expensive, compared to alternatives like photovoltaics and wind turbines.

And those are getting cheaper and cheaper at an incredible rate at the moment. So it's a moving target.

And yes, solar and wind rely on intermittent sources of energy, so you need to combine them with some kind of dispatchable source/storage to match the demand curve, but you have that too with a fission plant because of the high capital cost, and I don't see why it wouldn't be true for fusion too, unless somebody comes up with a way of building a really cheap fusion plant.

Re: Successful second round of fusion experiments with Wendelstein 7-X

#34

Post by ForHackernews »

antocv wrote: post #30
nine_k wrote: post #12

With fusion devices having trouble to confine the plasma for long times, I wonder if a massively-parallel fusion plant woud be feasible. Let's assume that plasma destabilisation does not damage the device, and is a mundane event. Build 10 or even 20 fusion devices (economy of scale!) feeding the common heat buffer, e.g. a large reservoir of a molten salt or metal. Feed conventional turbines off the heat of the heat t…

What is it with physicists and molten salt? Every battery-tech, pro-nuclear, fusion related news have to have somebody chiming in "molten salt". Just an observation.

Molten salt has a high heat capacity and a higher boiling point than water, so you can get higher temperature without worrying about steam.

Re: Successful second round of fusion experiments with Wendelstein 7-X

#35

Post by msslx »

saganus wrote: post #5

Does anyone have any idea how do they take pictures of the plasma? That seems quite hard considering the temperatures and the strong magnetic field.

Good question - I worked at the ASDEX Upgrade (AUG), also operated by the IPP but a tokamak instead of a stellarator: At AUG similar images and videos [0] are recorded by IR cameras. These cameras require strong cooling and a magnetic / electric shielding as described in [1]. Per plasma discharge (~10s) around ~8GB of video data is recorded. There are also fast frame cameras for dust tracking [2] and similar things. I assume the same techniques are applied at Wendelstein.

[0] https://www-ncbi-nlm-nih-gov.eaccess.ub.tum.de/pubmed/266281... [1] https://www.youtube.com/watch?v=QCK51vqWunU [2] http://iopscience.iop.org/article/10.1088/1741-4326/aa4e56

Re: Successful second round of fusion experiments with Wendelstein 7-X

#36

Post by [deleted] »

antocv wrote: post #30
nine_k wrote: post #12

With fusion devices having trouble to confine the plasma for long times, I wonder if a massively-parallel fusion plant woud be feasible. Let's assume that plasma destabilisation does not damage the device, and is a mundane event. Build 10 or even 20 fusion devices (economy of scale!) feeding the common heat buffer, e.g. a large reservoir of a molten salt or metal. Feed conventional turbines off the heat of the heat t…

What is it with physicists and molten salt? Every battery-tech, pro-nuclear, fusion related news have to have somebody chiming in "molten salt". Just an observation.

[deleted]

Re: Successful second round of fusion experiments with Wendelstein 7-X

#37

Post by [deleted] »

bicubic wrote: post #17
nine_k wrote: post #12

With fusion devices having trouble to confine the plasma for long times, I wonder if a massively-parallel fusion plant woud be feasible. Let's assume that plasma destabilisation does not damage the device, and is a mundane event. Build 10 or even 20 fusion devices (economy of scale!) feeding the common heat buffer, e.g. a large reservoir of a molten salt or metal. Feed conventional turbines off the heat of the heat t…

This doesn’t solve the fact that a single fusion pulse (all existing reactors are pulsed) currently consumes more energy than it produces.

[deleted]

Re: Successful second round of fusion experiments with Wendelstein 7-X

#38

Post by cygx »

empath75 wrote: post #26
ttul wrote: post #3

Experiments like Wendelstein remind me that the only thing holding back fusion power is money for research like this. Every year, we spend billions on fossil fuel exploration because the return on investment is quick - just think about all the wells going in to extract shale oil. What if we collectively had the will to invest this much into fusion?

If they had a clear path to fusion and money were the only thing in the way, money would flow into it from every direction. The problem is that nobody knows how to build a functioning reactor yet or if it's even possible to build a functioning reactor. It's very possible that we could throw trillions of dollars at this and still not figure it out.

It's very possible that we could throw trillions of dollars at this and still not figure it out.

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.

Re: Successful second round of fusion experiments with Wendelstein 7-X

#39

Post by nine_k »

Retric wrote: post #32
nine_k wrote: post #12

With fusion devices having trouble to confine the plasma for long times, I wonder if a massively-parallel fusion plant woud be feasible. Let's assume that plasma destabilisation does not damage the device, and is a mundane event. Build 10 or even 20 fusion devices (economy of scale!) feeding the common heat buffer, e.g. a large reservoir of a molten salt or metal. Feed conventional turbines off the heat of the heat t…

Ok, several issues with this. First restarting these devices takes a lot of electricity, which drastically reduces your net efficiency. So, you still really want to solve this problem. Second, fusion devices scale very well so one device at 10x the scale is vastly better than 10 different devices at x size. Third, storing and pumping heat involves losses, where there is a huge range of great options for storing elect…

> there is a huge range of great options for storing electricity

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.

Re: Successful second round of fusion experiments with Wendelstein 7-X

#40

Post by bseidensticker »

hyperbovine wrote: post #11
ttul wrote: post #3

Experiments like Wendelstein remind me that the only thing holding back fusion power is money for research like this. Every year, we spend billions on fossil fuel exploration because the return on investment is quick - just think about all the wells going in to extract shale oil. What if we collectively had the will to invest this much into fusion?

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…

We are spending a relatively pitiful amount of money on fusion power research. The US has spent $29B TOTAL in 2010 dollars from the 1950s through 2010. (I couldn't easily find global numbers, but I can't imagine it's more than an order of magnitude higher)

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

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