Best Size for a Polywell power plant?

If polywell fusion is developed, in what ways will the world change for better or worse? Discuss.

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cgray45
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Best Size for a Polywell power plant?

Postby cgray45 » Mon May 10, 2010 9:57 pm

Presuming the concept works, what do you think would be the most effective size for a polywell power plant (defined as the plant including 1 polywell system and associated power extraction gear).

While Bigger often is better, you also have to consider you want more than just one or two big power plants, so that taking one offline isn't difficult, and equally it's probably better to as much as possible bring the polywell to the areas requiring energy rather than have it half a country away with the associated wastage in transmission.

Also, for ground based civilian power generation, which would be better-- the traditional reactor>working fluid> turbine generator, or the methods currently expected to be able to extract energy directly from the reaction? While the latter is more effecient, it would require a good deal of retraining of workers, and the first method essentially lets you "plug in" polywell generators to a good deal of our existing infrastructure.

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Postby kunkmiester » Tue May 11, 2010 5:02 am

You'd have both systems. "Direct drive" is massively simpler and easier to build than turbines and such. Many polywells will be build to run P+B11 and will use this system. On the other hand, the amount of capital needed for a turbine will ensure that people who have been building them will eek out as much of a return on that investment as they can--newer coal plants will see the combustion chamber replaced with a D+D reactor that can boil the water for the turbines. Much less efficient, but more economical.
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cgray45
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Postby cgray45 » Tue May 11, 2010 8:24 am

kunkmiester wrote:You'd have both systems. "Direct drive" is massively simpler and easier to build than turbines and such. Many polywells will be build to run P+B11 and will use this system. On the other hand, the amount of capital needed for a turbine will ensure that people who have been building them will eek out as much of a return on that investment as they can--newer coal plants will see the combustion chamber replaced with a D+D reactor that can boil the water for the turbines. Much less efficient, but more economical.


Why would you use D+D for the water bioling version? Doesn't it's production of neutrons tend to cause problems with the longevity of the superconductors?

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Postby D Tibbets » Tue May 11, 2010 3:27 pm

cgray45 wrote:
kunkmiester wrote:You'd have both systems. "Direct drive" is massively simpler and easier to build than turbines and such. Many polywells will be build to run P+B11 and will use this system. On the other hand, the amount of capital needed for a turbine will ensure that people who have been building them will eek out as much of a return on that investment as they can--newer coal plants will see the combustion chamber replaced with a D+D reactor that can boil the water for the turbines. Much less efficient, but more economical.


Why would you use D+D for the water bioling version? Doesn't it's production of neutrons tend to cause problems with the longevity of the superconductors?


Good point, though it will probably depend on the superconductor. Certainly it would increase the heating of the magrids from neutrons, and the cooling needed. Then again, there will presumable be much more x-rays in a P-B11 machine...
Perhaps a compromise, as there will need for active cooling of even a P-B11 machine. Have a P-B11 machine that produces several megawatts of power directly, while the necessary cooling is used to power the on site steam cycle ( and cooling plant) of the otherwise decommissioned coal plant at near the turbines capacity. This way you lose some of the portability of your power systems, but you utilize the paid for steam systems. Larger scaling/ fewer sites may also have some cost scaling advantages.
Which costs more to build and operate- one large P-B11 Polywell, or two (or more) smaller Polywells?

Dan Tibbets
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cgray45
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Postby cgray45 » Tue May 11, 2010 7:00 pm

I don't know. The big questin would be would the savings in having your power plants close to the end user (and avoiding losses from transmission) override the expenses of having more power plants. OTH, the notational design we saw was for a 600MW power plant-- and it wouldn't take many of them to cover much of say, California. Spreading them out with smaller individual plants would also reduce the vulnerability of hte entire grid to a disaster at any given point.

Also, according to some material out there, their may be ways to reduce the X-ray and Gamma ray output by "clever engineering of the magnetic fields", although it then goes to discus all the reasons this would be difficult-- but certainly it seems that the long term future for the P+B11 reactoin might be far friendlier in the sense of not nuking the surrounding squishy organics then the other potential reactions.

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Postby kunkmiester » Tue May 11, 2010 9:38 pm

D-D reactor would be smaller and presumably cheaper. You're also not expecting a really long life, enough to pay for the turbines is really all you need--anything else is a nice extra.
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Postby MSimon » Wed May 12, 2010 6:13 am

cgray45 wrote:
kunkmiester wrote:You'd have both systems. "Direct drive" is massively simpler and easier to build than turbines and such. Many polywells will be build to run P+B11 and will use this system. On the other hand, the amount of capital needed for a turbine will ensure that people who have been building them will eek out as much of a return on that investment as they can--newer coal plants will see the combustion chamber replaced with a D+D reactor that can boil the water for the turbines. Much less efficient, but more economical.


Why would you use D+D for the water bioling version? Doesn't it's production of neutrons tend to cause problems with the longevity of the superconductors?


Engineering wise they are not serious problems.
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Postby MSimon » Wed May 12, 2010 6:16 am

These days utilities like to buy power plants in the 50MW to 200 MW range.

And because safety issues are minimal a Polywell could run unattended. Similar to many nat. gas peaking plants.
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Postby kunkmiester » Wed May 12, 2010 7:02 am

Or you could have a simple, single attendant to take care of all those coal miners and turbine operators that will eventually be put out of business. If the time and effort was taken after successful development, you'd be getting a trained force to help with it as the old stations and mines are shut down, and the unions would make sure that the old guys who can't/won't learn the new trade have sound pensions.

Never going to happen though.
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cgray45
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Postby cgray45 » Wed May 12, 2010 8:35 am

MSimon wrote:These days utilities like to buy power plants in the 50MW to 200 MW range.

And because safety issues are minimal a Polywell could run unattended. Similar to many nat. gas peaking plants.


I wouldn't go that far-- even a direct energy conversion polywell will likely need more than a few guys watching after it. Certainly lower than a natural gas plant, but I'd think not unattended-- at least not for some time.

Since Polywell reactors seem to be more effective at the larger range, would they buy such small designs? From what I understand, a 500 MW polywell reactor, presuming all other things equal, wouldn't be that much more expensive then a 200 MW one.

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Postby PMN1 » Wed May 12, 2010 2:11 pm

kunkmiester wrote:Or you could have a simple, single attendant to take care of all those coal miners
Never going to happen though.


Much less of a problem in the UK of course but it will be interesting to see how things go if a breakthrough is announced.


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