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benf wrote: Does this represent progress?
~snip~

Well… insofar as any mention of fusion is better than none 🙂

But the way that kind of Senate PR usually turns out is that ITER funding will get cut and then the domestic fusion programs so prominently mentioned will get little but cries of poor mouth and “austerity…”

… and all the while our drinking water gets fracked to hell and gone.

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Chuctanunda wrote: Great to hear about the triple plasmoid density achievement. I would like to know what is a realistic level of output above break even. What level of output will make this process economical? What level will make it competitive with conventional electricity production? Forgive me for being a little anxious, but I really want to see this work..

The folks at LPP use the term “scientific feasibility” instead of “break even”… a point at which it is demonstrated that the concept will work. As for the amount of joules per pulse they would expect to need to meet that criterion? 30,000 joules. It’s mentioned in the paper in the section about filament disruption:

If we can get yield up to our theoretical expectation of over 1 joule, our scaling calculations tell us that with higher current we can make it all the way to the 30,000 J that we need to demonstrate scientific feasibility.

… and the Sankey diagram on this page shows that they are going for about 66,000 joules for the proposed power generator.

Was this the sort of thing that you wanted to know?

[zapkitty]

A mystery appears… what could it be?

Attached files

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Maya wrote:
Right, but my point is that the issue is more fundamental than you seem to realize. In other words, it doesn’t matter what proposal you’re talking about if you don’t know how to calculate and contain pressure.

… actually, “it doesn’t apply” is a quite acceptable answer when a concept really doesn’t apply …

to quote:

“In fact the Focus Fusion dense plasma focus design goes one step further by allowing an unstable collapsing magnetic field to do the fuel compression… no external compression required. This is one of several neat ways that the FF concept takes advantage of natural instabilities.”

Each pulse should generate about 66 kilojoules of gross fusion energy from hydrogen-11 Boron… and yet the physical structure of the device does not support the compression of the fuel. (It did its work holding the device together when a few million amps of current was dumped into the electrodes 🙂 )

General Fusion’s rather baroque concept is another way around the “problem”… a sphere a couple of meters in diameter is hammered to create a converging spherical shockwave through molten lead that is spinning inside. When the shockwave arrives at the center the pressure is (hopefully) enough to initiate fusion in the plasmoid hanging in the vortex at the center of the spinning lead… and yet at no time is any point on the outside shell subjected to the immense pressure at the center of the vortex.

Are two examples enough to start?

Again, each of the fusion startups has their own way of handling the issue.

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Maya wrote:

Pretty much irrelevant since ITER and its costs are in no way a design paradigm for a commercial fusion reactor… even a tokamak 🙂

I think that mostly sums up your overall response, so I’ll just respond to that.

Actually, what I said was that for various reasons the limits you envision do not apply to many fusion concepts and I listed some of them and briefly described one of them 🙂

Perhaps you should read through what you called “IP proposals” again… each one has their own way of dealing with what you seem to have come to believe must be an insurmountable problem.

We can discuss the details of their various solutions if you’d like.

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Maya wrote: Yep, you did. The discussion is about fusion. Which costs more to build and run? Savannah River Site or ITER?

Pretty much irrelevant since ITER and its costs are in no way a design paradigm for a commercial fusion reactor… even a tokamak 🙂

Tokamak-style power reactors such as ITER are problematic in and of themselves and may not turn out to be workable power sources but if ITER does work out then the researchers intend to continue with DEMO, a demonstration power plant with at least 4 times the power output at 1/4 the cost.

And then they’ll try to segue the DEMO facility into PROTO, a prototype power plant… if they can.

And of course there are several current non-ITER fusion projects that operate by different rules altogether. Focus Fusion, Tri-Alpha, Polywell, Helion, General Fusion and whatever it is that Lockheed Martin calls the project that the Skunk Works is working on to name some of them.

And all of these are different projects with different designs (assuming that the lockmart design isn’t a polywell variant) and they all involve relatively small (12 to 100 MW) and inexpensive reactors that can be used to add to a distributed power grid to provide as much power as needed where it is needed.

As for your ideas about fusion economics some background on your figures would help. First you speak of single reactors providing hundreds of gigawatts at a minimum to be “viable” and then you speak of one (1) reactor that would supply all the worlds power and half again that much… how many such 21 terawatt reactors were you envisioning to be built?

Maya wrote:

The pB11 reaction is aneutronic in nature and units built along the lines envisioned by Focus Fusion, Tri-Alpha and the Polywell concept would be in the scale of a few megawatts to a gigawatt or so and their neutron flux would be pretty damn small.

It seems that you’ve set impossible-to-meet criteria and I look forward to learning what you envision as the solution to them 🙂

I don’t think so. I think the criteria are grounded in hard reality. I don’t believe that megawatt class fusion reactors will ever be economical in any foreseeable future. On this particular point the issue isn’t technical. It’s economic. Why would anyone build a megawatt class reactor that would be such a colossal construction for a single one-off?

… again, you seem to have confused ITER with actual commercial fusion power proposals.

Much of what you say is not applicable to commercial tokamak concepts and even less of it applies to non-tok designs… and none of it would seem to apply to aneutronic designs.

Maya wrote:
And the four key issues I described are part of the reason why I don’t think they’ll be economical. Even if you lower the power output you will still have phenomenal pressures to deal with. Have you looked at the structural loading on ITER

… again, you seem to have confused ITER with actual commercial fusion power plant proposals 🙂

Patient “Doctor it hurts when I do this.”
Doctor: “Then don’t do that.”

All of the non-ITER fusion startup concepts avoid the problem by handling much smaller fuel masses more efficiently than ITER. Their individual methods are different but none of them are trying to hold ITER’s 840 cubic meters of plasma at fusion temperatures.

In fact the Focus Fusion dense plasma focus design goes one step further by allowing an unstable collapsing magnetic field to do the fuel compression… no external compression required. This is one of several neat ways that the FF concept takes advantage of natural instabilities 🙂

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Maya wrote:
I can summarize the key 4 issues with fusion power that must be addressed for a _commercially viable_ (at least hundreds of gigawatts) reactor to work:

…?

Could you explain why you think that “at least hundreds of gigawatts” are required for a commercial fusion reactor?

Even the largest current fossil and fission power plants are at most 1-2 gigawatts per unit.

Or did I misunderstand and it’s the fusion concept you mentioned that requires that minimum size to be viable?

Maya wrote:
Only Hydrogen and 11 Boron can be used in any foreseeable design and even that will require enormous thermal management (H-11B still produces flux in power levels of 1 to 10 giga watts in a 21 TW reactor).

… a 21 terawatt pB11 reactor?

Why on Earth (and where on Earth) would you want to build a single reactor that would supply over half again the entire world’s current power needs?

The pB11 reaction is aneutronic in nature and units built along the lines envisioned by Focus Fusion, Tri-Alpha and the Polywell concept would be in the scale of a few megawatts to a gigawatt or so and their neutron flux would be pretty damn small.

It seems that you’ve set impossible-to-meet criteria and I look forward to learning what you envision as the solution to them 🙂

(PACER variant at 3-2)

[zapkitty]

Er… did you mean to put this under another category? This is the aneutronic thread 🙂

And as the hydrogen-boron fusion reaction is aneutronic (meaning that less than 0.2% of the reaction energy is carried by neutrons) then there just wouldn’t be enough neutrons generated from an FF unit to make much of anything into anything else… and that’s one of its strong points!

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As I understand it, it was to take place in a western usa time zone so a bit more patience will probably be needed 🙂

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Lerner wrote: We know the obvious stuff. What we really need is some work making a list of the many (dozens at least) of sites that specialize in clean energy and environmental news.

Okeydoke… suggest that we crowdsource it where feasible and post suggestions and candidate sites on this thread.

Also suggest that sites devoted to energy and the future in general be included, such as the Oil Drum…

[zapkitty]

Blogging sites that cover news and current events?

While social and political issues tend to dominate such, any news about energy and the environment tends to get attention and commentary.

[zapkitty]

errrr…

From the latest LPP report:

“In the next shot series, we will replace the washers with indium wire which has worked elsewhere on our electrodes to entirely eliminate even the tiniest arcing. We will also silver-plate the cathode rods as we have done with the anode. Over the longer run, we are looking at ways to have a single-piece cathode made out of tungsten or tungsten-copper in order to eliminate the rod-plate joint altogether.”

i.e. they are already planning to go to single-piece electrodes.

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So. It has come to this… yet again. It is as always and this too shall pass.

There was no reason whatsoever to ignore the multitude of suggestions to immerse a working unit in a tub of water, measure the results and remove all doubts.

… of course that part about removing all doubts is why it’s not going to happen.

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Patientman wrote: The issue of what local power companies and cites allow for power generation is a part of this question. In Minnesota, generation of more than 5 MW of electricity requires public hearings and a great deal of red tape. How do you tap into the system without a distribution station nearby? Do you incorporate it into the reactor building?

A 5MWe FF unit, which would be housed in a building about the size of a two-car garage, could be lost in one of the larger urban distribution yards 🙂

Such yards tend to combine a lot of latticework and empty space in between its massive components.

Attached find my rough idea of a “standard” 5MWe FF housing with an even rougher transformer set ready to feed to the current grid.

Attached files

[zapkitty]

vansig wrote: unlike traditional nuclear, which runs the plant continuously, focus fusion will consist of an array of small reactors, which could be switched on or off based on needed load.

… and those modules need not all be located in one building.

So FF units would be suitable for both integration into the current grid and infrastructure [em]and[/em] for helping to develop the distributed grid that, in the U.S. at least, is long overdue.

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