How long until a net power attempt

[rj40]

A while backed I asked if the WB-7 was capable of providing sufficient answers to questions so that, provided those answers were positive, a net power device could be attempted. Well, based on Alan Boyle’s last, it looks like the answer is no, it was not sufficient.

So, what has to be answered before most experts on this subject would be convinced? That is:
1. What are the top questions that need to be answered before most experts would agree it is time to go for a net power device?
2. How many more devices would it to take?
3. Provided adequate funding and enthusiasm were available TOMORROW, how long would it take to build those devices, analyze the results and then decide to go for net power device (assuming positive results, of course)? 3 years? 7 years?

[zbarlici]

I think that more testing is in store, before R. Nebel`s team jumps to the $200 million 100MW device.... The way the positive peer review announcement was made, it sounds like polywell still has to undergo more testing... i guess thats only fair considering the way the fusion claims have been made in the last 15 years or so?

[zbarlici]

i just hope the program`s funding will not be choked purposely... in an effort to slow down polywell development...

[Roger]

$200 million 100MW device....

Bussard spoke of a 200 million program, I don't think he ever said a 100MW device would cost 200 million..

I'd guess that WB-7 scaled up to 100MW could be built for as little as 25 million.

[MSimon]

$200 million 100MW device....

Bussard spoke of a 200 million program, I don't think he ever said a 100MW device would cost 200 million..

I'd guess that WB-7 scaled up to 100MW could be built for as little as 25 million.

And another $25 mill for buildings power supplies etc.

[joedead]

good question. anyone think Doc Nebel will be wading in anytime soon?

[tomclarke]

Whatever the WB-6 results no-one can be sure how it will scale. Building a bigger sub-net-power device will help estimate scaling laws but still leave some uncertainty - given that the theory of 3-D non-equilibrium plasma is too complex for us to be sure. Running a WB-6 sized device continuously will help answer some other questions but not guarantee scaling laws.

So it looks like some time yet!

Best wishes, Tom

[rj40]

Again, I was asking what has to be answered BEFORE a net power device would be attempted. It sounds like we have something like:

1. Can a pre-net device run continuously and for how long?
2. How do we build a carburetor?
3. Are the scaling estimates accurate?
4. What else?

And then, how many pre-net devices will it take to answer these questions? The answer might be something like:
Four. One to test scaling laws, one for carburetor development, one to run continuously, one to…???

You get the idea. I don’t know the questions or the answers, and so what you see above is mostly filler.

I wonder if it would be useful to have a continuously updated document (written for a general audience!) we can all view that lists the above; sort of a way to organize our thoughts/discussion. As more questions were discovered, they could be added to the list – hopefully in order of importance. As questions were answered, we could check each question off (we might actually see progress that way). That is assuming we ever get access to the results. Maybe MSIMON, Tom Ligon, and Art Carlson could maintain the thing.

[MSimon]

Again, I was asking what has to be answered BEFORE a net power device would be attempted. It sounds like we have something like:

1. Can a pre-net device run continuously and for how long?
2. How do we build a carburetor?
3. Are the scaling estimates accurate?
4. What else?

And then, how many pre-net devices will it take to answer these questions? The answer might be something like:
Four. One to test scaling laws, one for carburetor development, one to run continuously, one to…???

You get the idea. I don’t know the questions or the answers, and so what you see above is mostly filler.

I wonder if it would be useful to have a continuously updated document (written for a general audience!) we can all view that lists the above; sort of a way to organize our thoughts/discussion. As more questions were discovered, they could be added to the list – hopefully in order of importance. As questions were answered, we could check each question off (we might actually see progress that way). That is assuming we ever get access to the results. Maybe MSIMON, Tom Ligon, and Art Carlson could maintain the thing.

I'd be up for it.

Note: there was a long discussion at NASA Spaceflight around May of 2007 on the topic of a path to WB-100. Tom Ligon was pretty active then and had some good ideas.

[hanelyp]

I see at least 2 experimental devices before a net power attempt:
- a 'continuous' WB-7 scale device.
- a larger version of the above to validate scaling.

It might be good 'politics' if the first polywell expected to reach break even was not be publicly billed as such ahead of time, but simply the next step in the science to validate the figures derived from earlier models. If it does reach break even, a big announcement can be made after the results are validated. Avoid falling short of expectations by being conservative in promises made.

[TallDave]

Just hazarding a semi-informed opinion:

It seems the biggest potential pitfalls are in loss scaling. Since the physics are fast enough to test theory in a pulsed machine, I wouldn't be surprised if the next attempt were a larger, uncooled machine, perhaps even somewhere close to net power. That could either expose insuperable problems in basic Polywell theory or leave only the problems of continuous operation, without the expense of trinary cooling.

I don't know if you can get anywhere near 5-10T magnets in uncooled copper though, even for short pulses to sweep through beta, or how practical that would be given cooldown time. Maybe someone like Simon can tell us how close uncooled copper could get for practical purposes.

[ravingdave]

I think they should use the scaling equations to design a machine for net power, then add some size to it for "fudge factor" just to make sure, then build it. The scaling equations can be confirmed or not with any size machine, so it might as well be one that can be used to work out power generation details.

The machine should be cooled superconducting right from the start, but not necessarily intended for continuous operation. There is the chance that a sufficient neutron flux will destroy the magnetic field containing the electrons, and the massive discharge could ruin the machine.


Since (in my opinion) the biggest expenses are the large vacum vessel and pumping equipment, you might as well set the whole thing up so that you can blow up the "guts" (coils, guns, injectors) in an assembly line fashion.


David

[KitemanSA]

I see at least 2 experimental devices before a net power attempt:
- a 'continuous' WB-7 scale device.
- a larger version of the above to validate scaling.

I think at least one more should be resolved before net power, that of sphericity. To dodec or not.

[ravingdave]

I see at least 2 experimental devices before a net power attempt:
- a 'continuous' WB-7 scale device.
- a larger version of the above to validate scaling.

I think at least one more should be resolved before net power, that of sphericity. To dodec or not.

Seriously?

I may be misunderstanding something, but it seems to me that winding coils of one size is not much more difficult than winding them of another. All other problems being equal, what is the point in building a machine that can only tell you more about the scaling equations, as opposed to a machine that could give you some idea of how to build a power generating system.

I guess what i'm trying to say, whether it be dodec or whatever, the guts are relatively cheap. Build a test chamber and power supply system big enough to handle whatever you want to put into it.

David

[Roger]

A while backed I asked if the WB-7 was capable of providing sufficient answers to questions so that, provided those answers were positive, a net power device could be attempted. Well, based on Alan Boyle’s last, it looks like the answer is no, it was not sufficient.

HUH?
Is not DR Nebel lobbying the DOD for the next device ? Or have I missed something ?

In one sense, nothing has changed over the last 2 yrs. The issues about going forward have not changed. Alans blog changes nothing.

$200 million 100MW device....

Bussard spoke of a 200 million program, I don't think he ever said a 100MW device would cost 200 million..

I'd guess that WB-7 scaled up to 100MW could be built for as little as 25 million.

And another $25 mill for buildings power supplies etc.

Ok, 40-50 million.

My personal opinion: Dr. Nebel will build an approximately 1.6 meter pulse mode device to show net power and of course, scaling. Its been said for the last year or 2 that

Scaling
Dodec
Carburetor/continuous operation
Collection of alphs

Are probably the major issues facing commercial development. Net power and PB-11 are the 2 game changers. I see nothing over the last 2 yrs that change the basic logic about how to go forward.