tag:blogger.com,1999:blog-6911752388384243976.post7030590976685750982..comments2023-04-05T13:37:33.168+01:00Comments on IEC Fusion Technology: WB-100 Superconductor Magnet CoolingM. Simonhttp://www.blogger.com/profile/09508934110558197375noreply@blogger.comBlogger10125tag:blogger.com,1999:blog-6911752388384243976.post-68448720574553467452008-04-03T08:42:00.000+01:002008-04-03T08:42:00.000+01:00Colin,That is the purpose of the water jackets. To...Colin,<BR/><BR/>That is the purpose of the water jackets. To get the thermal load on the MRI magnets down to a level similar to what the MRI guys deal with normally.<BR/><BR/>The J factor is assumed based on what the MRI guys do every day.<BR/><BR/>I'm also assuming that the power conversion plant will not be a thermal one but electrostatic.M. Simonhttps://www.blogger.com/profile/09508934110558197375noreply@blogger.comtag:blogger.com,1999:blog-6911752388384243976.post-60469641716723683452008-04-03T06:56:00.000+01:002008-04-03T06:56:00.000+01:00The current density,J, will be effected by by the ...The current density,J, will be effected by by the conductor stablizer/semiconductor design. You may want to through a factor of 1/10 into your estimates.<BR/><BR/>I don't think MRI guys will be able to help much on the cryogenics. Any amount of heat transfer to the LHe equates to a big $. MRIs require LHe servicing, they don't work with the enormously expensive systems to cool LHe. The heating issues with MRI cryogenics is also on a much lower order of magnitude.<BR/><BR/>To handle the cryogenics for this you're looking at a several $100M facility, like ITER has. And ITER has much more thermal shielding between the plasma and coil. <BR/><BR/>My naive impression is that it would be more economical to have much lower power systems at higher Sc operating temperatures.<BR/><BR/>Also the structural considerations are not insignificant, and most experienced physicists would defer to an experienced ME on the matter. That would be one lesson from WB6.Unknownhttps://www.blogger.com/profile/00547244391519530808noreply@blogger.comtag:blogger.com,1999:blog-6911752388384243976.post-44907021437863610442008-04-02T00:52:00.000+01:002008-04-02T00:52:00.000+01:00colin,This is strictly back of the envelope stuff ...colin,<BR/><BR/>This is strictly back of the envelope stuff to suggest an approach.<BR/><BR/>The engineering details will have to be worked out in conjunction with an MRI magnet supplier in conjunction with the reactor requirement physicists.<BR/><BR/>The forces involved are in the ton range. Manageable.M. Simonhttps://www.blogger.com/profile/09508934110558197375noreply@blogger.comtag:blogger.com,1999:blog-6911752388384243976.post-83905092139107970472008-04-02T00:38:00.000+01:002008-04-02T00:38:00.000+01:00Most superconducting magnet designs I've seen inco...Most superconducting magnet designs I've seen incorporate a Cu or Al stabilizer around the superconductor. Is this something that's included in the superconductor in your cross section? <BR/><BR/>It seems like the thermal and field stresses on the the standoffs will be large. Have you considered standoffs robust enough to take this without conducting to much heat to the cryogenics? I think the efficiency of cryogenic systems is about 1/400.Unknownhttps://www.blogger.com/profile/00547244391519530808noreply@blogger.comtag:blogger.com,1999:blog-6911752388384243976.post-37872671256700761182008-03-26T14:38:00.000+00:002008-03-26T14:38:00.000+00:00Water will not be much of a problem. It has to be ...Water will not be much of a problem. It has to be pH 7 to keep the high voltage isolated.<BR/><BR/>I was thinking that copper might be good for the various "tubes" of the grid. Of course it might have to be some low activation steel to support the magnetic forces.<BR/><BR/>Eddy currents will not be a problem because other than a slow charge up the magnetic field is fixed.<BR/><BR/>Magnetically saturated steel will not be an issue because I wasn't expecting any help from the steel re: the magnetic fields.M. Simonhttps://www.blogger.com/profile/09508934110558197375noreply@blogger.comtag:blogger.com,1999:blog-6911752388384243976.post-23400285317934326112008-03-26T13:10:00.000+00:002008-03-26T13:10:00.000+00:00How do all those steel / inconel / water layers af...How do all those steel / inconel / water layers affect permittivity? <BR/><BR/>Aren't you going to get eddy currents where the inlets/outlets through various layers connect?Tom Cuddihyhttps://www.blogger.com/profile/00998611274249390948noreply@blogger.comtag:blogger.com,1999:blog-6911752388384243976.post-40299013577782292752008-02-06T20:45:00.000+00:002008-02-06T20:45:00.000+00:00There are reasons for making the H2O fluid surroun...There are reasons for making the H2O fluid surround the whole coil.<BR/><BR/>One is that you will get some mixing from the "cold" to the "hot" side improving heat transfer which I expect will be marginal to begin with. <BR/><BR/>Near the coils themselves the magnetic field will be roughly circular. So it may not be necessary to construct a special shape for the outer cooling loop.<BR/><BR/>I'm going to add a bit about neutron shielding to the main text.M. Simonhttps://www.blogger.com/profile/09508934110558197375noreply@blogger.comtag:blogger.com,1999:blog-6911752388384243976.post-52082652551552853702008-02-06T16:03:00.000+00:002008-02-06T16:03:00.000+00:00With reference to Dr Bussard's notes on wiffle-bal...With reference to Dr Bussard's notes on wiffle-ball confinement and the magrid: the optimum shape for the coil casing of a magrid is one that is conformal to the magnatic field lines that set up around it; with wiffle-ball confilement this shape is approximately an ellipse with one flattened end, i.e. a kind of elongated 'D' shape. The flat part of the D faces inward toward the center of the polywell. It should be noted that the cause of both heating and sputtering on the coil canister is high-energy Helium ions coming from the fusion in the center of the polywell, and this will hit the coil canister from one direction only - impacting on the flat face of our elongated 'D' shape. Therefore only this face needs high-temperature cooling (600k water or sodium), and only this face needs anti-sputter coatings (boron or titanium) the rest can be polished stainless-steel. Additionally, there is room in the rounded part of the 'D' for a more massive stainless steel supporting structure, and ducting to carry liquid He and N2 coolants. Hope this helps.Martin Chttps://www.blogger.com/profile/03375234607778447256noreply@blogger.comtag:blogger.com,1999:blog-6911752388384243976.post-3293737886796509412008-02-06T03:44:00.000+00:002008-02-06T03:44:00.000+00:00Indrek did some simulations with round vs. square ...Indrek did some simulations with round vs. square and found that by the time the field meets the surface of the grid there was no significant difference.<BR/><BR/>The added "empty" volume gives a place for coolant flow.M. Simonhttps://www.blogger.com/profile/09508934110558197375noreply@blogger.comtag:blogger.com,1999:blog-6911752388384243976.post-11715754686109517722008-02-06T01:50:00.000+00:002008-02-06T01:50:00.000+00:00I like the cross sectional detail drawing. Is the...I like the cross sectional detail drawing. Is there an engineering reason to make the magnet at the center square instead of round? I thought the big lesson from WB-6 was to make everything round. Or does that only apply to the outer charged surface?layounghttps://www.blogger.com/profile/13517540659056233618noreply@blogger.com