EMC2 news

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

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Skipjack
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Re: EMC2 news

Postby Skipjack » Wed Sep 16, 2015 12:25 am


D Tibbets
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Re: EMC2 news

Postby D Tibbets » Wed Sep 16, 2015 4:37 am

D-T fusion is for the timid :x . At least that is my bias. I don't know why Parks promoted this fuel for the Polywell, asside from my speculation. From the start, D-D fusion has always been the Polywells basic target. From an intermediate experimental setup perspective, the problems with handling tritium is significant. D-D is a much easier approach from an experimental/ engineering perspective. If fusion power by measuring neutron output is your metric, D-D is just as good, if not superior. Less shielding, easier thermalization of the neutrons, etc. As with the Japanese Tokamak, burning D-D fuel gave (I think) good measurements that can be directly extrapolated to D-T fuel predictions. Money and time is saved with this approach and I suspect that money and time will remain the major challenge for any of the projects pursuing useful fusion technology. This even applies to ITER, though on a much larger scale.

I agree that the Polywell may be a poor choice for D-T fusion. The internal magnets would be exposed to a lot of neutron bombardment. Note though that the Lockheed design has similar magnet exposure, and liquid salt cooling is proposed to handle the neutron flux. With tritium breading requirements I assume the metal in the liquid metal salt would be mostly lithium. Conversely, the X ray exposure in a D-T machine will be less, perhaps much less when considering aneutronic alternatives. This was Riders contention. I remain unconvinced of D-T viability, not so much due to triple product considerations, but due to the tritium breeding challenges and the mostly unexplored diverter technology. I wonder how much a pulsed approach (of a few milliseconds) in a FRC or other ignition (ie: thermalized) machine relaxes the challenges of the diverter. I understand it will be a major concern for the Tri Alpha FRC.

Concerning Art Carlson's efforts against Eric Learner, my understanding was that mostly it was directed towards the LPP Wikipedia page. He actually managed to ban Learner from editing the page, which was ironic. considering it was his project. He criticized R. Nebel on a physics forum, and after some back and forth the debate shifted to Talkpolywell, where the arguments and counter arguments continued for a time. Whatever Art Carlson's motives were, the back and forth was enlightening and educational. The openness of R. Nebel was also refreshing, I wish it had continued.

Dan Tibbets
To error is human... and I'm very human.

Skipjack
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Re: EMC2 news

Postby Skipjack » Wed Sep 16, 2015 9:11 am


mvanwink5
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Re: EMC2 news

Postby mvanwink5 » Wed Sep 16, 2015 11:49 am

With plasmas, real world machines and well designed experiments settle the arguments, and Park's proof on Grad's cusp plugging theory put to rest the major arguments against Polywell. Until then, it was a lot of postulating. Now, the $30M machine is needed to finish settling the remaining arguments. I am sure Art is happy with positive results even though he was dubious.
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

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Re: EMC2 news

Postby alexjrgreen » Wed Sep 16, 2015 1:39 pm



Tritium production looks like a licence to print money. When I spoke to Tokamak Energy at the Royal Society's Summer Science Exhibition, they were also talking about D-T and a Lithium blanket to breed more.
Ars artis est celare artem.

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Re: EMC2 news

Postby crowberry » Wed Sep 16, 2015 3:48 pm


ladajo
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Re: EMC2 news

Postby ladajo » Wed Sep 16, 2015 8:38 pm

The development of atomic power, though it could confer unimaginable blessings on mankind, is something that is dreaded by the owners of coal mines and oil wells. (Hazlitt)
What I want to do is to look up C. . . . I call him the Forgotten Man. (Sumner)

Skipjack
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Re: EMC2 news

Postby Skipjack » Wed Sep 16, 2015 11:32 pm


ladajo
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Re: EMC2 news

Postby ladajo » Thu Sep 17, 2015 12:44 pm

The development of atomic power, though it could confer unimaginable blessings on mankind, is something that is dreaded by the owners of coal mines and oil wells. (Hazlitt)

What I want to do is to look up C. . . . I call him the Forgotten Man. (Sumner)

D Tibbets
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Re: EMC2 news

Postby D Tibbets » Thu Sep 17, 2015 3:03 pm

Dumping tritium into a reaction chamber is easy, essentially no different than deuterium. The problems with tritium is the regulatory and management loop holes you have to go through to handle it. Exhausting the reactor contents also,requires careful management of the unburned tritium. I suspect just diluting it may be inadequate, you would need to sequester it. This would probably be a very small part of the budget for an ITER scaled experiment, but for these smaller efforts clawing for barely adequate funding, the issue is not trivial. Handling the highly energetic D-T produced neutrons is defiantly, probably, possibly ( :? ) a major issue for any production reactor. I suspect the damaging and heating effects on superconductors may be the biggest issue. Materials management may mitigate induced radiation in the structure, but to keep the superconductors cold and durable, thicker first wall shielding is required. As, admitted, this may be countered at least in part due to the less X-rays at the colder D-T fusion temperatures. For a production machine that has to meet durability goals, it is another level of development. Well, sort of, deuterium- deuterium fusion is not exactly neutron free. In a Polywell or Lockheed type cusp machine though, only about 1/2 of the KE is carried by the neutron, and the total is less per reaction (works both ways in the arguement). The charged He3 and tritium produced would exit through the cusps so this component bypasses the magnet cans- significantly less cooling concerns for themagnets. All of this applies mostly to a production machine.

Admittedly, in a research, relatively low power machine, these issues are perhaps much less significant. And, the psychological impact of achieving real breakeven is much more convincing than projected breakeven based on D-D fusion results. The Japanese Tokamak reached breakeven with projected D-T fusion, based on their D-D fusion results, but publically at least, it is only a side note... I have no idea how much it contributed to ITER decision making.

My vision for a minimal useful terrestrial fusion industry is D-D fusion for main grid supply. This might be boosted by recycling the produced tritium ( part of the 1/2 catalyzed reaction) and B10 neutron capture boosting. But high efficiency tritium production requirements are avoided, no additional lithium first wall technology needed for development. D-He fueled reactors would be reserved for mobile low neutron producing reactors like in ships or spacecraft. Obviously, the grid D-D reactors would have to far exceed the mobile aneutronic reactors in total power production in order to provide the needed He3. Of course, P-B11 fusion , if possible, changes the entire game. But, this is a goal that probably needs to be pursued after viability of easier practical fuels is achieved.

There are only two reasons to pursue D-T reactions in my mind :shock: , the aforementioned psychological effects / bragging rights, and a high level of confidence that your system will only work with this easiest fuel.
My bias is that the highly preferred goal should be a minimum of D-D fusion. D-T is highly suspicious option, in my mind at least, when talking about an economically viable, useful power production industry.

As for profitable fusion, the baseline is not really D-T fusion, but Solar fusion. Here the physics are solved, the engineering is free for the basic reactor. Here the issues are the conversion of the delivered power into electricity or other forms of useful energy, and of course the constancy of the supply. Solar panels, Wind, even fossil fuels or biodiesel are simply conversions of this Solar fusion power. Cost, very long term aviability, and constancy of supply are the issues that determines if a system is actually useful. Fusion is here and proven, as demonstrated by the Sun. Other than Scientific curiosity , pursuing terrestrial fusion should be governed by the above goals. I feel that D-T fusion, at least along the ITER Tokamak path is a dead end. I am much less certain if alternate D-T fusion approaches are viable. My point is that if there is reasonable expectation that at least D-D fusion can be made to work in a machine, then it is reasonable to bypass the headaches (both large and small) associated with D-T fusion. The politics and perceptions are the primary advantages of persuing D-T fusion, not the end goals of a useful industry. This is based on my profound and unassailable expertise (cough... 8) .

Dan Tibbets
To error is human... and I'm very human.

paperburn1
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Re: EMC2 news

Postby paperburn1 » Thu Sep 17, 2015 5:42 pm

I'm sure the whole reason why they are going with a DT machine is purely political. Once they show that they are capable of producing excess energy with their DT machine. All they have to do is make the simple statement if I had more money I could make even more energy to sell at a profit. Investors lined up around the block waving their checks and screaming take my money. And I'm sure Jay Park is a very smart man and when he builds his demo machine to be very easily able to be retrofitted into a DD machine or even possibly a D PB 11
but before any of the suitors even get that far they need to show that they can produce excess power. And in the money will pour it as this is a classic example of first past the post technology. It will not matter if somebody has a better idea or a better machine because in the short-term the person that produces excess power will get all the funding.
I am not a nuclear physicist, but play one on the internet.

Skipjack
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Re: EMC2 news

Postby Skipjack » Thu Sep 17, 2015 8:37 pm


ladajo
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Re: EMC2 news

Postby ladajo » Thu Sep 17, 2015 9:29 pm

The development of atomic power, though it could confer unimaginable blessings on mankind, is something that is dreaded by the owners of coal mines and oil wells. (Hazlitt)

What I want to do is to look up C. . . . I call him the Forgotten Man. (Sumner)

Skipjack
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Re: EMC2 news

Postby Skipjack » Thu Sep 17, 2015 10:41 pm


bennmann
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Re: EMC2 news

Postby bennmann » Fri Sep 18, 2015 2:49 am

Relevant to the discussion are simple, confirmed neutron counts. AFAIK, EMC and Park et al have the most promising history of neutron counts to date.

Those little bubbles make the evidence seeking part of my brain tingle. Having said that, it's almost a shame that info was missing from the cusp EMC paper.... I bet someone here has seen more recent numbers for that though...

Didn't Lerner do a burn recently...? Or was that just a kev test shot? Any neutron producing burns lately from any of the front runners anyone here knows about ?


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