Talk-Polywell.org

A Q=0.001 would be absolutely astounding at this early stage. It would move IEC up an order of magnitude, before any of the multitude of "tunings" are applied.

I'd be great if they could simply see their way to such a development.

TallDave wrote:

My current understanding (based on prices) is that the $200 million follow on effort would include several test reactors to test scaling laws, losses, and any thing else needed for engineering WB-100.

Interesting, I had assumed from earlier reading that that was just for the 100MW reactor itself.

If that estimate is even close to accurate, the economics are awfully compelling.

Dave,

That is what I thought too until I did some back of the envelope calculations.

Think about it: A set of MRI magnets cost less than $1 million. Upgrade for high alpha flux and you are up to maybe $5 million. Power supplies: say 25 MW at a dollar a watt (experimental price). Vacuum vessel and pumps: say $5 million (experimental). Add another $50 million for engineering services and you are still under $100 million. So where does the other $100 million go? Has to go into a small continuous operation test reactor and other test reactors and the people to do the work.

Speaking of economics - $1 a watt capital cost is the magic number for back of the envelope estimation.

Below that and we have a real winner.

I can foresee mass produced BFRs at $.25 a watt.

Helius wrote:A Q=0.001 would be absolutely astounding at this early stage. It would move IEC up an order of magnitude, before any of the multitude of "tunings" are applied.

Especially considering they're using copper windings.

scareduck wrote:

Helius wrote:A Q=0.001 would be absolutely astounding at this early stage. It would move IEC up an order of magnitude, before any of the multitude of "tunings" are applied.

Especially considering they're using copper windings.

A .3 m .5T LN cooled Cu coil would require 100 KW of cooling while in operation. At .6 m (where a Q of .001 is possible) if you go with the B field scaling (to 1T) your power to cool (and for the coils) is 1 MW (roughly).

That is probably the limit for LN cooled Cu. I do not see them as production devices unless POPS greatly increases the power out for small devices. And even then - LN will have to be supplemented with H2O.

MSimon wrote:First wall problem

Is that the outer vessel wall? (I'm sorry, what is the first wall problem?)

IIRC, the "first wall problem" is how to deal with the immense waste heat in an operational Polywell fusion device.

dch24 wrote:

MSimon wrote:First wall problem

Is that the outer vessel wall? (I'm sorry, what is the first wall problem?)

It is the problem of high energy ions impacting the magnetically shielded grids.

The first wall problem is more than a waste heat problem. There is also the more significant problem of sputtering non-reactive atoms into the reaction space. That will be very difficult to solve.

MSimon wrote:

TallDave wrote:

My current understanding (based on prices) is that the $200 million follow on effort would include several test reactors to test scaling laws, losses, and any thing else needed for engineering WB-100.

Interesting, I had assumed from earlier reading that that was just for the 100MW reactor itself.

Dave,

That is what I thought too until I did some back of the envelope calculations.

Think about it: A set of MRI magnets cost less than $1 million. Upgrade for high alpha flux and you are up to maybe $5 million. Power supplies: say 25 MW at a dollar a watt (experimental price). Vacuum vessel and pumps: say $5 million (experimental). Add another $50 million for engineering services and you are still under $100 million. So where does the other $100 million go? Has to go into a small continuous operation test reactor and other test reactors and the people to do the work.

Hmm now I remember why I thought that: Bussard said intermediate sizes were a "waste of time." He made reference to one more small device to validate and extend the WB-6 results (essentially what Nebel, Wray, Park, etc are doing now).

http://www.emc2fusion.org/

I would guess the other $100M was wiggle room for the engineering challenges mentioned above.

Interesting tidbit here:

http://www.emc2fusion.org/RsltsNFnlConc ... 120602.pdf

Costs tend to scale as the cube of the system size and the square of the B field. Thus, full-scale machines and their development will cost in the range of ca $ 180 – 200 M, depending on the fuel combination selected.

Dave,

I think there is a requirement (from an engineering perspective) for a continuously operating machine before going to a full scale demo.

As Tom pointed out previously: Even Dr. B. thought the idea will not be proved enough for scale up until we understand the longer time scales. He always envisioned continuous experimental operation.

I think we need to do WB-7x before committing to a full scale reactor.

I don't want to be bitten by "what all else".

I think there is a requirement (from an engineering perspective) for a continuously operating machine before going to a full scale demo.

I certainly don't disagree.

I think Bussard was in a hurry because he knew he didn't have much time left, and wanted to sell a demo project rather than the lead-up to a demo project.

I think Bussard was in a hurry because he knew he didn't have much time left

Stupid cancer sticks.

scareduck wrote:

I think Bussard was in a hurry because he knew he didn't have much time left

Stupid cancer sticks.

If he was the creative genius I think he was the odds are he was slightly schizophrenic. Very common among creative types.

Schizophrenia and Tobacco

rj40 wrote:What ARE the questions being asked on this? I thought they were looking for supporting evidence as to whether a BFR will actually produce net power. But come to think about it, I don't really know. If I am right I guess we should expect an announcement similar to one of the below:

1. We have essentially confirmed our theory that a BFR will produce net power. We recommend moving on to a full-scale power producing model.
2. We have essentially refuted our theory. We were wrong. We recommend moving on to something else with respect to this use.
3. We have inconclusive results. We still don't know. We recommend ...?

Does this sum it up?

I would guess they would be as follows.

Verifying neutron were indeed produced and were not just noise from his equiptment.

If the fusion rate is proportional to the square of the density, you have beam-beam fusion, absolutely necessary for getting passed break even, if the fusion rate is just proportional to the 1st power of the density you have beam background, from which you can get respectable neutron counts from but don't have a hope in hell of ever getting net power out of.

If you know the edge density and you know the neutronm count you can calculate the convergence ratio. A criticism of Polywells is the claim that the aspherical shape of the potential well could rapidly destroy convergence, tests on WB-7 could confirm or deny this.

Then there's edge annealing, I'm reliably informed that despite the theory there is no conclusive experimental evidence to date for edge annealing in a Polywell, it will be of vital importance to, in addition to producing neutrons verify that the beam retains its non-maxwellian characteristics in excess of thie ion-ion collission time.