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Dynomak In The News and Polywell Too
Posted: Sat Oct 11, 2014 4:21 am
by MSimon
Re: Dynomak In The News and Polywell Too
Posted: Sat Oct 11, 2014 1:07 pm
by mvanwink5
Has anyone asked Sutherland about 1st wall yet? Clearly that detail has been vetted in their penciled economics or else the pencilled economics had a shredded last page...
It is only a matter of time for EMC2 to have backing for their first risk reducing project step, surely? Let's hope it is not like the $1.5M table scraps thrown on the floor for Helion by Mithril Capital and YCombinator... On the other hand, it may be that that is all that would be required to shred the last WB-D doubt and trigger serious cash and heat up the Dark Horse fusion race?
Stay tuned, I am sure we will find out what didn't happened bit by....xx years... bit.
edit:
After further story of Helion chasing, it looks like the $1.5M to Helion is part of a risk management funding roadmap with series B staged for late mid 2015 assuming testing milestones met along the way.
Re: Dynomak In The News and Polywell Too
Posted: Sat Oct 11, 2014 3:09 pm
by birchoff
mvanwink5 wrote:Has anyone asked Sutherland about 1st wall yet? Clearly that detail has been vetted in their penciled economics or else the pencilled economics had a shredded last page...
It is only a matter of time for EMC2 to have backing for their first risk reducing project step, surely? Let's hope it is not like the $1.5M table scraps thrown on the floor for Helion by Mithril Capital and YCombinator... On the other hand, it may be that that is all that would be required to shred the last WB-D doubt and trigger serious cash and heat up the Dark Horse fusion race?
Stay tuned, I am sure we will find out what didn't happened bit by....xx years... bit.
I was going to fire an email to him given the correspondence aceshigh shared. But I was wondering, the crux of the first wall issue has everything to do with the material that is used to make up the inner wall between the plasma and heat exchanger correct? That is what ever material you choose, the options we currently have all have the same problem; i.e neutron embrittlement. Is that correct
Re: Dynomak In The News and Polywell Too
Posted: Sat Oct 11, 2014 3:26 pm
by mvanwink5
There is some bizarre surface erosion that also takes place, then there is tritium breeding using lithium. 1st wall is a major design issue from what i have read. It is a Tokamak bete noire.
Re: Dynomak In The News and Polywell Too
Posted: Sat Oct 11, 2014 3:35 pm
by D Tibbets
Neutron embrittlement?
It depends on the design and fuel. Certainly D-T and to a lesser extent D-D fuel will produce lots of neutrons, but what happens to them is important. In a Tokamak, or General fusion or any other scheme that plans to use D-T fuel the first wall has to be a neutron absorbing- tritium producing substance- generally liquid lithium that is continuously recycled with tritium extraction. The neutron enbrittlement issue is trivial in this situation (compared to the lithium blanket issues). In D-D reactors the enbrittlement issue is real and has to be addressed. If you use D-He3 or especially P-B11 fuel the neutron issues are much to tremendously less of a concern.
Dan Tibbets
Re: Dynomak In The News and Polywell Too
Posted: Tue Oct 14, 2014 11:37 pm
by TheRadicalModerate
As usual, I'm confused.
The abstract
here says this is a spheromak. Have these guys made a genuinely stable spheromak? How? And wouldn't that make General Fusion pretty much a slam-dunk?
Re: Dynomak In The News and Polywell Too
Posted: Wed Oct 15, 2014 4:08 pm
by Skipjack
D Tibbets wrote:
Certainly D-T and to a lesser extent D-D fuel will produce lots of neutrons
If you do tritium suppressed (and HE boosted) pulsed DD Fusion, like Helion does, the neutrons are a lot less of a problem.
I agree with the issues for the Dynomak since it is burning TD. I think they are smaller than for a tok, since the device is smaller too.
Re: Dynomak In The News and Polywell Too
Posted: Wed Oct 15, 2014 10:03 pm
by birchoff
mvanwink5 wrote:Has anyone asked Sutherland about 1st wall yet? Clearly that detail has been vetted in their penciled economics or else the pencilled economics had a shredded last page...
It is only a matter of time for EMC2 to have backing for their first risk reducing project step, surely? Let's hope it is not like the $1.5M table scraps thrown on the floor for Helion by Mithril Capital and YCombinator... On the other hand, it may be that that is all that would be required to shred the last WB-D doubt and trigger serious cash and heat up the Dark Horse fusion race?
Stay tuned, I am sure we will find out what didn't happened bit by....xx years... bit.
edit:
After further story of Helion chasing, it looks like the $1.5M to Helion is part of a risk management funding roadmap with series B staged for late mid 2015 assuming testing milestones met along the way.
I fired off an email to Derek Sutherland and got the following response about the first wall issues
Derek Sutherland wrote:
Using inductive helicity injection as opposed to electrostatic, we do not have line tying to our electrodes and thus we don't have a diverted magnetic topology like SSPX. We also do not pull nulls in any location that leads to an intersection of magnetic field lines with the wall. As a result, the power is assumed to come out isotropically on the first wall with ~ 1 MW m^-2 wall loading and a high neutral density at the edge that helps take the power out radiatively as well. This whole topic is a key issue to address in the next experiment, HIT-SIX, which seeks to demonstrate IDCD in higher temperature plasmas. I do have a few ideas of how the power exhaust will work more microscopically with a high temperature plasma, but I'm going to wait for the next experiment that seeks to address this issue in more reactor relevant conditions before really describing it in detail... there's only so much you can do with theoretical and computational calculations.
He also extended an offer to do a "Ask me [Derek Sutherland] anything" at some point.
Re: Dynomak In The News and Polywell Too
Posted: Wed Oct 15, 2014 10:31 pm
by mvanwink5
Thanks birchoff, and especially thanks to Dr. Sutherland for answering the first wall question.
It would be nice to see adequate support for all the non-consensus fusion projects. Fusion news is coming out of the woodworks, but I guess that is to be expected once the competition for funds hits high C.