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Discuss the technical details of an "open source" community-driven design of a polywell reactor.

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MSimon
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Post by MSimon »

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http://www.energy-daily.com/reports/Fin ... s_999.html

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This may or may not help Polywell. The problem is that Lithium under neutron bombardment generates Tritium.
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WizWom
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Post by WizWom »

Not as critical in a non-burning polywell as in tokamak.

We have stuff NOW that will handle a 100 MW polywell, or even a 500 MW polywell.

And like i said, increasing the flow rate of the coolant for the superconductors will allow you to handle massive amounts of heat with normal materials; see the U-2 wing edge and the Saturn-V rocket bell.
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MSimon
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Post by MSimon »

WizWom wrote:Not as critical in a non-burning polywell as in tokamak.

We have stuff NOW that will handle a 100 MW polywell, or even a 500 MW polywell.

And like i said, increasing the flow rate of the coolant for the superconductors will allow you to handle massive amounts of heat with normal materials; see the U-2 wing edge and the Saturn-V rocket bell.
Cryo cooling is OK for cryo fueled rockets. It is rather more expensive than if you used water to do the bulk of the cooling in a Polywell and only used cryo coolants for minimal heat flows.
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WizWom
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Post by WizWom »

MSimon wrote:
WizWom wrote:Not as critical in a non-burning polywell as in tokamak.

We have stuff NOW that will handle a 100 MW polywell, or even a 500 MW polywell.

And like i said, increasing the flow rate of the coolant for the superconductors will allow you to handle massive amounts of heat with normal materials; see the U-2 wing edge and the Saturn-V rocket bell.
Cryo cooling is OK for cryo fueled rockets. It is rather more expensive than if you used water to do the bulk of the cooling in a Polywell and only used cryo coolants for minimal heat flows.
Cryo cooling is imperative for superconducting coils, which are imperative for the high magnetic fields. Putting a second cooling system into the casing means you need even higher magnetic fields to accommodate the additional bulk.

Think of the polywell as a target for cooling in an heat pump; the external side will take the N2 steam and compress it, raising its temperature. That high temperature N2 will then be cooled first by a water heat exchanger, then by a secondary N2 system. It's a considerable job, but within proven engineering. And you should be able to get a significant portion of the enthalpy into usable work.

You don't want water in the core anywhere - it acts as a neutron moderator, which will thermalize a portion of the neutrons in a D-D core, and increase the radiation damage to the superconductors, which would be very expensive. For light to medium Z atoms, as in most high temperature superconductors, the fast neutron cross section is very low but a slow neutron becomes a real problem.
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MSimon
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Post by MSimon »

Cryo cooling is imperative for superconducting coils, which are imperative for the high magnetic fields. Putting a second cooling system into the casing means you need even higher magnetic fields to accommodate the additional bulk.


Maybe, Maybe not. The additional distance might be useful so that the field is more regular at the face of the coil.

Think of it - 1 Mw (for example) at 77K vs 1Mw at 600K. The lower temperature is going to eat up a LOT of KWs. Also if you can afford 2" to 4" of water you can absorb thermalized (by the water) neutrons rather easily. A thin coating of B10 will do nicely. This improves SC life.

http://iecfusiontech.blogspot.com/2008/ ... oling.html
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