General Fusion in the news

Point out news stories, on the net or in mainstream media, related to polywell fusion.

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paperburn1
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Re: General Fusion in the news

Post by paperburn1 »

General fusion now has additional funding from Amazon and Shopify. looks like they have enough money to build the darn thing. :D
I am not a nuclear physicist, but play one on the internet.

crowberry
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Re: General Fusion in the news

Post by crowberry »

Here are some details on what General Fusion is planning to do:
With shovels in the ground within the next two years, the design of the Demonstration Plant is expected to introduce the world to fusion power – a path forward to mitigating climate change by integrating Science and Nature.
Donaldson adds that over the next year the Company is looking to double the size of their team and they are on the lookout for bright engineers, scientists, technology experts and researchers who support the common solutions oriented goal of transitioning the world to a sustainable low-carbon future. “Check out our career opportunities page.”
https://www.watertoday.ca/ts-renewable- ... n-grid.asp

crowberry
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Re: General Fusion in the news

Post by crowberry »

General Fusion has posted a new video on this page: https://generalfusion.com/2021/03/using ... gy-future/. It seems that they have moved from a spherical geometry to a cylindrical geometry according to the 11 s long video on that page?

Giorgio
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Re: General Fusion in the news

Post by Giorgio »

Very interesting, they are going to give a spherical shape to the shock wave by delaying the hit time of the pistons. This will also reduce mechanical stress load on the structure.
It looks like a smart idea, at least in theory.
A society of dogmas is a dead society.

crowberry
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Joined: Sun Sep 08, 2013 6:34 am

Re: General Fusion in the news

Post by crowberry »

Giorgio wrote:
Fri Mar 26, 2021 8:03 pm
Very interesting, they are going to give a spherical shape to the shock wave by delaying the hit time of the pistons. This will also reduce mechanical stress load on the structure.
It looks like a smart idea, at least in theory.
Yes, you are right about their intention to use a spherical shock wave in the cylindrical chamber by shaping in time the piston compression. GF has released a new 1 min 52 s long video which explains their ideas for their fusion demonstration plant https://www.youtube.com/watch?v=KRk9Ud4egmo.

It would be interesting to know the dimensions of the cylindrical chamber? The plasma injector on the top of the chamber looks much shorter than their current big prototype. They have two layers of pistons in this design, larger outer ones and smaller ones inside the rotating chamber.

mvanwink5
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Re: General Fusion in the news

Post by mvanwink5 »

Originally they were going to use lead for the molten metal, but the issue was the surface of the compression shock wave had small droplets that would eject from the metal surface into the plasma which would quench the reaction. To deal with that their thought was to use a thin layer of lithium so that the droplets would not be lead, but would be lithium. Then they went to an all lithium molten metal compression fluid.

The idea behind the shock wave was speed of compression. It was thought that the plasma stability lifetime would be too short for just compression and that the speed of a shock wave would be required. Plasma injector test program, however was so successful, finding a plasmoid that would stay stable under adiabatic compression longer than they originally thought possible, and due to the issue of plasma quenching droplets, now lithium, they have since moved away from a shock wave.

The change to a cylinder makes the manufacturing time shorter, cylinder milling vastly easier, so the ultimate cost to manufacture is much lower. Moreover, maintenance is easier and requires no skill change for utility workers.

Given their testing at near full scale of plasma injector and other compression components, it is no wonder they are going for the demo plant.

I think this will be one of the competitive fusion island alternatives.
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

mvanwink5
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Joined: Wed Jul 01, 2009 5:07 am
Location: N.C. Mountains

Re: General Fusion in the news

Post by mvanwink5 »

One 'small' detail I missed in their new design is that the internal pistons and liner that is in contact with the molten lithium rotates in synchronism with the molten metal. The driving pistons and thicker outer vessel then is stationary and is coupled with the inner pistons with some kind of working fluid (don't know what that is and they don't say). It is a bit more involved than I thought and of course more money...I can't see how they would have achieved this easily in a spherical compression chamber.

It all looks to be directed towards a stable compression of the molten lithium.

Best regards
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

Giorgio
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Re: General Fusion in the news

Post by Giorgio »

mvanwink5 wrote:
Wed Apr 07, 2021 1:15 pm
The driving pistons and thicker outer vessel then is stationary and is coupled with the inner pistons with some kind of working fluid (don't know what that is and they don't say).
The first impression I got from the movement of the piston in the animation is that it could be some type of magnetic coupling to push the inner piston inside while the centripetal force would take care of bringing them into original position.

Also, whatever the coupling will be, the inertia of the inner pistons will pay a non trivial role in finding the right balance to create a uniform pressure wave.
This is quite a radical change from the first design and to be honest I like it for its boldness. This is the way experimental engineering should be.
A society of dogmas is a dead society.

crowberry
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Re: General Fusion in the news

Post by crowberry »

General Fusion has published a new paper (paywalled) A stable corridor for toroidal plasma compression:
Abstract

A toroidal plasma compressed by a collapsing flux conserver is analyzed to reveal stable scenarios of operation to high compression ratios. The resistive and ideal MHD stability is calculated in full toroidal geometry, using the asymptotic matching method in realistic conditions, and comparing with nonlinear simulations. The near edge current profile, controlled by toroidal field ramping during compression, is shown to be critical to stability due to coupling between poloidal components of the least stable mode. The extension of a length of shaft on axis is also found to be critical at high compression, as the resulting good curvature region in magnetic field stabilizes pressure driven modes that would otherwise be unstable. This work extends from previous studies, which initially showed the existence of a stable scenario, to include findings of more extensive stable zones, detailed effects of geometry, and nonlinear simulations of the instabilities. The nonlinear simulations of the compression are consistent with the linear analyses, confirming both the conservation and stability properties.
https://doi.org/10.1088/1741-4326/abe68c

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