General Fusion in the news

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

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crowberry
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Re: General Fusion in the news

Postby crowberry » Mon Oct 16, 2017 3:34 pm

mvanwink5 wrote:Real news courtesy of crowberry. Thanks as usual.
https://arpa-e.energy.gov/sites/default ... ABERGE.pdf
• Designing a ~1.5 m radius liquid lithium plasma formation and compression machine
• ~1MA of plasma current spherical tokamak starting plasma (MAST/NSTX class)
• Sub-breakeven but high performance (10 keV at 7e16 cm-3)
• Still costing the machine but estimate ~100 M$
• 3-5 years project
• Will try to raise this money towards the end of this year

I was surprised GF would go for this small machine due to decreased piston number and contamination thereby, but the lithium seems to be their workaround for that. I guess lower $ risk is the bottom line with non Gruberment guys. Also low oil price due to fracking has hurt the oil sands backers. Cash flow?


In what sense do you think the GF prototype machine will be small? In 2009 they discussed a 2 m radius sphere, but since then the radius they mention for the prototype/full scale reactor has been 1. 5 m. The price tag of 100 M$ is lower though than the numbers they have thrown around earlier.

It would be interesting to know what kind of results General Fusion got from their PCS15 explosive test? Probably we will hear that at the next Fusion Power Associates meeting in December http://aries.pppl.gov/FPA/fpn17-16.shtml.

crowberry
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Re: General Fusion in the news

Postby crowberry » Fri Oct 27, 2017 11:14 am

General Fusion has published all of their seven poster contributions from the 59th Annual Meeting of the APS Division of Plasma Physics at their home page: http://generalfusion.com/research-library/.

There is an Motherboard article We Were Promised Fusion Energy by Daniel Oberhaus on the Z machine and General Fusion. The article is accompanied by an eleven minutes five seconds long video which also shows both the Z machine and General Fusions facilities. https://motherboard.vice.com/en_us/article/43nwp3/fusion-energy-explainer-z-machine-general-fusion-sandia-national-labs

mvanwink5
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Re: General Fusion in the news

Postby mvanwink5 » Mon Oct 30, 2017 11:47 pm

In what sense do you think the GF prototype machine will be small?

It is small to my mind as my brain translated radius to diameter. :roll: :oops: But, yes, 1.5 M radius is full size.
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

mvanwink5
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Location: N.C. Mountains

Re: General Fusion in the news

Postby mvanwink5 » Tue Nov 07, 2017 1:49 pm

A poster update gives a new strategy on GF's compression using pistons. A huge change from 'acoustic shock wave' to rapidly collapse the plasma to a slower non-acoustic compression. The new strategy requires longer sustained stable plasma, which is why the spherical tokamak plasma is needed. Also, the working liquid metal will be lithium as opposed to lead.

Here is the poster that succinctly outlines their new plan.
http://generalfusion.com/wp-content/upl ... erview.pdf
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

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

Re: General Fusion in the news

Postby crowberry » Wed Nov 22, 2017 1:39 pm

Dr. Peter O'Shea from General Fusion has given a talk at TRIUMF on Unlocking Fusion Energy With New Technologies. This is the best summary so far of where General Fusion stands and what the plans are. There is a lot of new content in this presentation: http://generalfusion.com/wp-content/uploads/2017/11/20171118-General-Fusion-TRIUMF-Talk.pdf

mvanwink5
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Location: N.C. Mountains

Re: General Fusion in the news

Postby mvanwink5 » Wed Nov 22, 2017 2:09 pm

Well, we are at the end of 2017, so Pi3 should be ready or nearly ready. One injector (top) instead of 2 (top and bottom), lithium, which was already clear that was a change from lead, beta = 20% is a detail I had hot seen before. One thing is not clear to me is the lithium vs lead makes a huge difference in built in shielding. I have no idea what that means for the device though.
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

crowberry
Posts: 452
Joined: Sun Sep 08, 2013 6:34 am

Re: General Fusion in the news

Postby crowberry » Wed Nov 22, 2017 3:42 pm

General Fusion has put forward from the very start also the possibility of using only one plasma injector. With the self similar creation and compression of a spherical tokamak this is the only solution.

GF has struggled with plasma impurities (like LPP Fusion). GF solved the issue with lithium coating of the surfaces in the plasma injector. Lead in the plasma will cool the plasma very fast so that needs to be avoided. It could be that the prototype system will only use lithium to avoid the possibility of lead contaminations in the plasma and simplify the setup in that way. I still think that GF will use a molten lead-lithium mixture in their final device. Avoiding lead contamination in the final device will of course require more work then to solve that possible problem

mvanwink5
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Location: N.C. Mountains

Re: General Fusion in the news

Postby mvanwink5 » Wed Nov 22, 2017 4:18 pm

With the self similar creation and compression of a spherical tokamak this is the only solution.

Yes. Thank you for that. I always wondered about that issue with the double ended FRC's such as TAE and Helion. But TAE handles it with scrape off + NBI. Helion...?

WRT lead, I wonder if they will ever go back? Just for shielding?
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

Skipjack
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Re: General Fusion in the news

Postby Skipjack » Wed Nov 22, 2017 5:34 pm

mvanwink5 wrote:
With the self similar creation and compression of a spherical tokamak this is the only solution.

Yes. Thank you for that. I always wondered about that issue with the double ended FRC's such as TAE and Helion. But TAE handles it with scrape off + NBI. Helion...?

WRT lead, I wonder if they will ever go back? Just for shielding?

I know that PPPL is using a SOL in their FRC, was not aware of TAE doing the same. Are you sure about this?
As for Helion, even though quite old by now, this paper should give you a basic idea of what they are doing:
http://www.fusion.ucla.edu/FNST/Renew_P ... 20talk.pdf

mvanwink5
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Re: General Fusion in the news

Postby mvanwink5 » Wed Nov 22, 2017 5:58 pm

SOL seems to be used by all the FRC's.

Stability on collision has been my doubt on Helion. Looks like they had that figured early on based on that pdf. hmmm, I am always suspicious of too easy / good to be true plasma tales, but they have the funding so they must have some trick up their sleeve.
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

Skipjack
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Joined: Sun Sep 28, 2008 2:29 pm

Re: General Fusion in the news

Postby Skipjack » Thu Nov 23, 2017 12:37 am

mvanwink5 wrote:SOL seems to be used by all the FRC's.

Stability on collision has been my doubt on Helion. Looks like they had that figured early on based on that pdf. hmmm, I am always suspicious of too easy / good to be true plasma tales, but they have the funding so they must have some trick up their sleeve.

Yeah, they figured that out years ago. Mind you, TEA is also merging two FRCs and at only a slightly lower speed. The main difference is that they are not compressing them at the same time like Helion does but rather hold the resulting single FRC in place for as long as they can. I think the bigger problem could be plasma stability during the rapid compression with magnetic fields rather then stability because of the merging, which which is sufficiently well understood by now. My other concern would be the extremely high magnet fields that they need for compression. There are some challenges associated with that. That said, they have been making really good progress with all of aspects of their reactor, especially after they finally managed to get a sufficient flow of funds to support their experiments.

mvanwink5
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Re: General Fusion in the news

Postby mvanwink5 » Thu Nov 23, 2017 1:36 am

SkipJack
I think the bigger problem could be plasma stability during the rapid compression with magnetic fields rather then stability because of the merging,


Crowberry's comment:
General Fusion has put forward from the very start also the possibility of using only one plasma injector. With the self similar creation and compression of a spherical tokamak this is the only solution.


Many times this last year I related GF's struggle to maintain plasma stability under compression (they already had stability before compression, just adiabatic performance under compression was their problem). GF tried many different spheromak shapes to achieve this, finally settling on their current one. Now, Crowberry is stating that colliding two spheromaks causes problems with the plasma under compression, but that is just what Helion is trying to do... The difference is Helion is using magnetics for compression and GF is using their pistons. So GF can't do it and has a moved to a single spheromak plasma injector. Helion does not have that option.

I have questioned the notion that all Helion has to do is simply collide two spheromaks and compress them because I have been watching GF struggle with this.

Finally you admit it is a challenge, but it is more than a challenge and GF has abandoned it. At least that is what Crowberry is saying. I am not saying it can't be done, but GF with a lot more money has gone to a single injector.

None of these Fusion schemes is a done deal, but the plasma stability under compression seems to be a huge milestone. GF seems to have passed that (assuming PI3 is successful - to be in service end of this year) as has TAE with C-2U (old news). TAE is working on raising the plasma temperature with NBI in C-2W, in service now. Next year we should hear of TAE's results.
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

Skipjack
Posts: 5953
Joined: Sun Sep 28, 2008 2:29 pm

Re: General Fusion in the news

Postby Skipjack » Thu Nov 23, 2017 9:06 am

mvanwink5 wrote:SkipJack
I think the bigger problem could be plasma stability during the rapid compression with magnetic fields rather then stability because of the merging,


Crowberry's comment:
General Fusion has put forward from the very start also the possibility of using only one plasma injector. With the self similar creation and compression of a spherical tokamak this is the only solution.


Many times this last year I related GF's struggle to maintain plasma stability under compression (they already had stability before compression, just adiabatic performance under compression was their problem). GF tried many different spheromak shapes to achieve this, finally settling on their current one. Now, Crowberry is stating that colliding two spheromaks causes problems with the plasma under compression, but that is just what Helion is trying to do... The difference is Helion is using magnetics for compression and GF is using their pistons. So GF can't do it and has a moved to a single spheromak plasma injector. Helion does not have that option.

I have questioned the notion that all Helion has to do is simply collide two spheromaks and compress them because I have been watching GF struggle with this.

Finally you admit it is a challenge, but it is more than a challenge and GF has abandoned it. At least that is what Crowberry is saying. I am not saying it can't be done, but GF with a lot more money has gone to a single injector.

None of these Fusion schemes is a done deal, but the plasma stability under compression seems to be a huge milestone. GF seems to have passed that (assuming PI3 is successful - to be in service end of this year) as has TAE with C-2U (old news). TAE is working on raising the plasma temperature with NBI in C-2W, in service now. Next year we should hear of TAE's results.

You miss the point! Helion is using magnetic fields for compression. They actually tried using liners (plasma liners) for compression in experiments in the mid 2000s (IIRC it was George Votroubek who was investigating that idea at the time). They found that Sloughs concept of using magnetic fields was a lot more suitable for a reactor. GF is trying to it with a liquid liner and it is a good idea, but they face their own set of challenges compared to Helion. E.g. compressing the plasmoids with a liquid liner takes a lot longer than with magnetic fields.
It just is not a good idea to judge the problems of Helion by the problems of GF and the other way round.
Helion conducted experiments confirming their scaling laws a long time ago. There are still uncertainties, but they can not be deducted from the issues GF has encountered. The two concepts are too dissimilar.
Obviously merging two FRCs into a single one has been working very well for TAE. Helion is just doing it a bit faster and is compressing them with magnetic fields (much quicker than the liquid liner of GF) towards the center. This process is relatively well understood by now as are the scaling laws going with it. E.g. Helion is at 5 keV plasma temperature now, 10 times as much as GF.

mvanwink5
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Re: General Fusion in the news

Postby mvanwink5 » Thu Nov 23, 2017 10:45 am

Nice claims, we'll see.
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

Skipjack
Posts: 5953
Joined: Sun Sep 28, 2008 2:29 pm

Re: General Fusion in the news

Postby Skipjack » Thu Nov 23, 2017 3:18 pm

mvanwink5 wrote:Nice claims, we'll see.

They had the papers and research to back them up years ago :)
And their later research was so encouraging that they figured they would be able to switch from D+T to D+ He3 and still get a high enough Q to have an economic reactor. If for some reason, they can't make D + He3 work, they can always fall back to D+T, at least for the first products until they have figured out the kinks.
Personally, I still wished they had found more support for their initial goal to have a fusion- fission- hybrid first. That would have been within reach for a while now but it is a tough sell, mainly for cultural and political reasons.


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