Please let this be true. Helium and no neutrons? Man I hope this works that would be an incredible breakthrough. Only 200 million dollars? It sounds too good to be true but I hope it's not.
Actually, aneutronic fusion is well-understood and not a Bussard invention. p-b11 is just the most accessible of several candidate reactions.
http://en.wikipedia.org/wiki/Aneutronic_fusion
The article is wrong about there not being any neutrons; there will be some 11B + α fusion and other reactions. They will be less than 1% of the fusion products, though, according to the theory.
Ahh okay. That makes more sense TallDave. I was wondering how 12C -> 8B + 4He -> 3 4He was not going to have neutron emission since there is obvious decay. Still though, <1% is a very cool number.
The thing I find odd is why Vinod Khosla or the other titans of SV venture capital aren't funding this sort of thing. While this is a far better use of my tax money than most state spending, I'd rather see this done by the private sector.
However what bothers me about the article is the lack of any reference to recent breakthrough(s) on the technical challenges. These challenges were fairly formidable last I heard.
So perhaps this is just be a push, albeit a warranted push, to overcome those difficulties.
Well, the article is correct that the reactions it details release no neutrons. But it's not a completely tidy environment; there are side reactions. The wiki describes this in some detail.
Foobar/Sandi,
The same reason DARPA invented the Internet: it's not a mature (i.e. commercial) technology.
That said, Paul Allen has funded a similar IEC effort by the Rostoker/Monckton team, which recently scored $40M in VC funding. They believe it will be commercial within 15 years.
How do you turn the energy into electricity in this scheme?
There are two possibilities. One is to use D/D fusion to boil water and turn a turbine, like conventional nuclear, coal, and other thermal power plants.
But with p-B11 fusion, there is another option. The fusion outputs from p-B11 are highly energetic helium nuclei, or alpha particles. You can simply run alpahs into a magnetic field and generate DC current at 2MV, with no thermal cycle (which is also vastly more efficient; no thermal losses and you've eliminated a lot of hardware). This is fairly trivial from an engineering perspective, though most DC converters currently only convert up to .6MV.
How could anyone possibly put a dollar cost ($200MM) on a commercial plant at this early stage in the development? This kind of thing does not improve their credibility.
Well, he's just extrapolating from the WB-6. Bussard has said $200M is a ballpark figure (iirc it's a $100M to $200M range).
Given that he believes he has produced a working model in the WB-6, it's not unreasonable, though everyone concedes there will need to be at least one intermediate device (and probably two), which is what they're building now.
To my knowledge, no one has ever built a way to capture fusion products and boil water with in a steady state mode (or pulse with a fequency high enough to be useful), and the MHD scheme has never been used as other than a topping-cycle for combstion generated plasma because of cost. Off the top of my head, temperature &Bremsstralung are pretty daunting for the kinds of equipment required.
I expect the cost to develop and build the generator side of the plant might equal the cost of the fusion reactor, although I'm not an expert &am open to other information.
If this is ever more than a science experiment then I'll climb on the band wagon, and certianly I'm in favor or R&D and prototyping, but not at the expense of starving other efforts at energy R&D.
Well, the thermal generation cycle is a relatively simple concept compared to getting the sustained fusion reaction in the first place.
Direct conversion of alphas to electricity is a lot less plant-intensive, if they can fuse p-B11, which is why everyone talks about it. But they may put in a thermal cycle anyway, to put the waste heat to some use and to hedge their bets (even if they can't fuse p-B11, they might still be able to do D/D fusion, which is lower energy). Even the magnet cooling system may be used to generate power.
We'll see what Bussard can do in the next couple years. If WB-7 can do what Ligon and Bussard think it can, it will be a watershed event for fusion power.
And its entirely possible Rostoker and Monckton will beat them to it.
Building DC convertors is a trivial exercise. If these things go production, the convertors will follow. Plus, you can always string convertors together. 10x .6MV = 1x 6MV (or pretty close). I'm still not sure how these things are going to work. The technical and theoretical challenges are still huge. I'm suspicious that he was never able to run WB-6 continuously. That worries me.
Well, WB-6 wasn't designed to run continuously (it didn't even have injectors capable of the feat, let alone the requisite cooling system). It was only intended to prove that the polyhedral magnetic concept can produce fusion by creating a deep potential well -- something others have claimed isn't possible because the system would collapse to thermodynamic equilibrium.
Once the concept is proven, then the thereotical challenges are essentially over and only the engineering challenges remain.
The fact that such a huge cooling system is required is part of what bothers me. Also, don't discount the engineering challenges. The cooling system might need to be so big that it won't fit into the reactor, which could scuttle the whole works. Stupid, simple stuff like that can be a real problem. I'm optimistic that this can work, I just question how great it'll actually be once it hits production. There's still a lot that can go wrong with this thing.
Sure, I guesstimate only a 1 in 3 chance this will actually lead to commercial power production. Still, a 1 in 3 shot at something as world-changing as this could be is definitely worth a few million in funding.
Yeah- compared to tokamaks, polywells look like a sure thing, and we've dumped untold billions into that. Kind of like the much vaunted "Hydrogen Economy", which I think is a political smoke and mirror show that allows candidates to throw money at a car "with water as its exhaust!" and look all green.
The innovation of the poly-fusion device seems to me based on reducing losses with a tight, uniform mag-field. If cooling (like with water) absorbs the energy of the fusion products in the area where the field is generated, then there is a hole in the mechanism that kills what makes it work where others have failed. Alternatively, if the field is collapsed at intervals to let the products stream out like an internal combustion exhaust cycle, it has to somehow get to water at pressure capable of running a steam turbine, or be directed into an MHD cycle.
These are high-kinetic energy charged particles. HIGH energy. Room temperature has an average kinetic energy somewhere around 0.03 eV. Combustion produces somewhere around 40 eV per atom burned. Fusion releases something in the low MeV (1,000,000 eV) range. That has profound implications for how energy is converted to electricity.
X-rays are produced by decelerating charged particles, i.e., hitting a metal target with electrons accelerated magnetically. Often the targets are tungsten because of the high melting temp (temp is a measure of the average KE of material). Frequently the target is cooled because the KE of the electrons is deposited in the target. Fusion reactions with particles in the MeV range where the KE is converted to something else will cause the particles to slow down (either thermal or MHD), releasing x-rays at very high energy. For perspective, typical medical x-ray is much less than 0.1 MeV and extremely short duration to protect the patient and the x-ray tube.
Inventing some kind of new steam generator converting high MeV particles outside to heated water inside is not trivial (fission reactors do the conversion inside the fuel). MeV radiation damages metal by producing local hot-spots that cause large thermal stresses and/or dislocation of atoms (they get moved because of the kinetic energy transferred to the atom).
A fission reactor releases like 200 MeV per fission, but the charged particles are stopped in the fuel where the Bremsstralung (German for slowing down) radiation gets lost in the radiation produced from the fission. The fuel is pretty much destroyed before it's finished. It starts out as a hard ceramic, ends up like chalk.
MHD is not complicated by radiation in combustion processes because the maximum Bremsstralung energy is the maximum the KE of the charged particle; combustion releases around 40 eV, the energy of light is somewhere around 0.5 eV. You get maybe UV particles, which generally isn't enough energy to create big material problems. If you rob MeV particles of KE (i.e. converting to some other form of energy), then you generate radiation which can create problems in materials.
MHD is interestingly a good way to reduce pollution from fossil plants, as particles in the plasma-exhaust get their KE removed and fall out.
You could possibly avoid all this hassle and get a "useful" device by using the polyfusion concept to make a bomb. Big energy release, not worried about how to control it. If there isn't enough energy release for a big bang, might still be an easy way to trigger a DT thermonuclear device without a fission based bomb. The process seems kind of complicated to put into a warhead, but the first nuclear weapons were platform based. Could be a way to get funded for research that could eventually evolve into power production.
We are the richest (or second? richest) state in the Union. Yet we have one of the worst public school systems in the union, lots and lots of underfunded government pensions, 2 billion we are spending on stem cells, and now the governor is pulling a PR stunt. This is sad.
Now, I DO support fusion, but not like this. This is the wrong set of priorities. If anything, we should be building fission reactors close to the ocean here is southern california, and lots of them, so in case the southwest gets a perfect storm situation and we run out of water, we can desalinate it from the ocean. The Energy Dept. wants to build a full sized prototype of a new type of safe fast reactor (the I.F.R. design). We should get it built here.
Every year we vote on all these bonds to be issued. It's ALWAYS for the schools, hospitals, etc. It's always the "feel good about yourself and vote for the children" crap for bond issue. I'm so disgusted by the lack of budget restraint that I now vote against ALL bonds, no matter what. If they want a new bridge, or more salaries for the teachers, then tax us today to pay for it, not our children. This "run up the credit card" mentality could really screw us over. The ability for the people to place a bond measure on the ballot should be removed, it's being abused, that's why our state's bonds have to pay such a high rate, because it's financially irresponsible. Whose going to bail us out? The federal government? HA! There's a small group of Republicans in the California government that has voted against every single budget for the last 2 decades or so. I used to think of them badly, now I side with them. I bet our elected officials are counting on the children of illegal immigrants to balance the budget.
If I could dedicate my life to a single cause, it would be to make California a Republican state. That would change everything. But with San Francisco, you can forget about that ever happening. But sometimes when I spend time in Orange County I think it's possible.
If cooling (like with water) absorbs the energy of the fusion products in the area where the field is generated, then there is a hole in the mechanism that kills what makes it work where others have failed.
Well, fusion products escape the well. The magnetic field is only intended to confine electrons, not ions, and the electron well that accelerates the ions won't confine fusion products. Alpha particles will pop right out of the well and through the magnetic field, and hit a collection grid surrounding the polywell device in a p-Bll setup, creating DC current. In D/D fusion, you'd just put a water-jacket around the device and use the heat to turn a turbine.
You can't make a polywell bomb, because Polywell isn't a thermal fusion system, it's electric. In order to produce militarily useful kinetic/heat power, you would need something the size of a factory to produce the magnetic field, and gigantic capacitors to boot. And even then it's a not a runaway process like a fission-fusion bomb; it won't fuse fast enough to "detonate." And it would cost way too much.
If California is funding this, it's almost certainly throwing the money away. The extrapolation of the experiments so far to reactor conditions involves increasing power by eleven orders of magnitude or so, and moving to a harder to fuse fuel. This is simply outrageous.
Worse, there's excellent theoretical reason to think the idea cannot work at all, due to loss of energy from the beam ions to electrons (even if the beams can be formed and confined). This was pointed out years ago by Rider in his masters and Ph.D. theses at MIT (later turned into published papers), and never refuted by Bussard or coworkers in the peer reviewed literature. Other showstoppers also exist, such as very rapid degradation of the ion energy distribution due to ion-ion scattering. Again, this has not been refuted in the peer reviewed literature.
Your site is amaizing. Can I share some resources with you? notem6715
9.25.2007 8:50pm
Commenting on Dean's World is a privilege, not a right. Dean is your host, you are his guest, and you should behave in that fashion. Dean is not your babysitter, nor is he your punching bag. Please remember this. In general, you are free to disagree with anyone on any subject you wish, but abusive behavior will not be tolerated.
Of course we all lose our tempers now and then. Dean freely admits to being imperfect in this regard, which is why regulars to this establishment will generally be cut more slack than people who we don't know very well.
Still: behave like an adult, or go find somewhere else to play. Thanks.
http://en.wikipedia.org/wiki/Aneutronic_fusion
The article is wrong about there not being any neutrons; there will be some 11B + α fusion and other reactions. They will be less than 1% of the fusion products, though, according to the theory.
However what bothers me about the article is the lack of any reference to recent breakthrough(s) on the technical challenges. These challenges were fairly formidable last I heard.
So perhaps this is just be a push, albeit a warranted push, to overcome those difficulties.
Foobar/Sandi,
The same reason DARPA invented the Internet: it's not a mature (i.e. commercial) technology.
That said, Paul Allen has funded a similar IEC effort by the Rostoker/Monckton team, which recently scored $40M in VC funding. They believe it will be commercial within 15 years.
Bussard believes his last experimental Polywell machine, WB-6, was the technical breakthrough for Polywell.
There are two possibilities. One is to use D/D fusion to boil water and turn a turbine, like conventional nuclear, coal, and other thermal power plants.
But with p-B11 fusion, there is another option. The fusion outputs from p-B11 are highly energetic helium nuclei, or alpha particles. You can simply run alpahs into a magnetic field and generate DC current at 2MV, with no thermal cycle (which is also vastly more efficient; no thermal losses and you've eliminated a lot of hardware). This is fairly trivial from an engineering perspective, though most DC converters currently only convert up to .6MV.
Well, he's just extrapolating from the WB-6. Bussard has said $200M is a ballpark figure (iirc it's a $100M to $200M range).
Given that he believes he has produced a working model in the WB-6, it's not unreasonable, though everyone concedes there will need to be at least one intermediate device (and probably two), which is what they're building now.
To my knowledge, no one has ever built a way to capture fusion products and boil water with in a steady state mode (or pulse with a fequency high enough to be useful), and the MHD scheme has never been used as other than a topping-cycle for combstion generated plasma because of cost. Off the top of my head, temperature &Bremsstralung are pretty daunting for the kinds of equipment required.
I expect the cost to develop and build the generator side of the plant might equal the cost of the fusion reactor, although I'm not an expert &am open to other information.
If this is ever more than a science experiment then I'll climb on the band wagon, and certianly I'm in favor or R&D and prototyping, but not at the expense of starving other efforts at energy R&D.
Well, the thermal generation cycle is a relatively simple concept compared to getting the sustained fusion reaction in the first place.
Direct conversion of alphas to electricity is a lot less plant-intensive, if they can fuse p-B11, which is why everyone talks about it. But they may put in a thermal cycle anyway, to put the waste heat to some use and to hedge their bets (even if they can't fuse p-B11, they might still be able to do D/D fusion, which is lower energy). Even the magnet cooling system may be used to generate power.
We'll see what Bussard can do in the next couple years. If WB-7 can do what Ligon and Bussard think it can, it will be a watershed event for fusion power.
And its entirely possible Rostoker and Monckton will beat them to it.
Ryan
Well, WB-6 wasn't designed to run continuously (it didn't even have injectors capable of the feat, let alone the requisite cooling system). It was only intended to prove that the polyhedral magnetic concept can produce fusion by creating a deep potential well -- something others have claimed isn't possible because the system would collapse to thermodynamic equilibrium.
Once the concept is proven, then the thereotical challenges are essentially over and only the engineering challenges remain.
I'm glad someone around here understands this stuff because I sure don't.
Ryan
Ryan
The innovation of the poly-fusion device seems to me based on reducing losses with a tight, uniform mag-field. If cooling (like with water) absorbs the energy of the fusion products in the area where the field is generated, then there is a hole in the mechanism that kills what makes it work where others have failed. Alternatively, if the field is collapsed at intervals to let the products stream out like an internal combustion exhaust cycle, it has to somehow get to water at pressure capable of running a steam turbine, or be directed into an MHD cycle.
These are high-kinetic energy charged particles. HIGH energy. Room temperature has an average kinetic energy somewhere around 0.03 eV. Combustion produces somewhere around 40 eV per atom burned. Fusion releases something in the low MeV (1,000,000 eV) range. That has profound implications for how energy is converted to electricity.
X-rays are produced by decelerating charged particles, i.e., hitting a metal target with electrons accelerated magnetically. Often the targets are tungsten because of the high melting temp (temp is a measure of the average KE of material). Frequently the target is cooled because the KE of the electrons is deposited in the target. Fusion reactions with particles in the MeV range where the KE is converted to something else will cause the particles to slow down (either thermal or MHD), releasing x-rays at very high energy. For perspective, typical medical x-ray is much less than 0.1 MeV and extremely short duration to protect the patient and the x-ray tube.
Inventing some kind of new steam generator converting high MeV particles outside to heated water inside is not trivial (fission reactors do the conversion inside the fuel). MeV radiation damages metal by producing local hot-spots that cause large thermal stresses and/or dislocation of atoms (they get moved because of the kinetic energy transferred to the atom).
A fission reactor releases like 200 MeV per fission, but the charged particles are stopped in the fuel where the Bremsstralung (German for slowing down) radiation gets lost in the radiation produced from the fission. The fuel is pretty much destroyed before it's finished. It starts out as a hard ceramic, ends up like chalk.
MHD is not complicated by radiation in combustion processes because the maximum Bremsstralung energy is the maximum the KE of the charged particle; combustion releases around 40 eV, the energy of light is somewhere around 0.5 eV. You get maybe UV particles, which generally isn't enough energy to create big material problems. If you rob MeV particles of KE (i.e. converting to some other form of energy), then you generate radiation which can create problems in materials.
MHD is interestingly a good way to reduce pollution from fossil plants, as particles in the plasma-exhaust get their KE removed and fall out.
You could possibly avoid all this hassle and get a "useful" device by using the polyfusion concept to make a bomb. Big energy release, not worried about how to control it. If there isn't enough energy release for a big bang, might still be an easy way to trigger a DT thermonuclear device without a fission based bomb. The process seems kind of complicated to put into a warhead, but the first nuclear weapons were platform based. Could be a way to get funded for research that could eventually evolve into power production.
Now, I DO support fusion, but not like this. This is the wrong set of priorities. If anything, we should be building fission reactors close to the ocean here is southern california, and lots of them, so in case the southwest gets a perfect storm situation and we run out of water, we can desalinate it from the ocean. The Energy Dept. wants to build a full sized prototype of a new type of safe fast reactor (the I.F.R. design). We should get it built here.
Every year we vote on all these bonds to be issued. It's ALWAYS for the schools, hospitals, etc. It's always the "feel good about yourself and vote for the children" crap for bond issue. I'm so disgusted by the lack of budget restraint that I now vote against ALL bonds, no matter what. If they want a new bridge, or more salaries for the teachers, then tax us today to pay for it, not our children. This "run up the credit card" mentality could really screw us over. The ability for the people to place a bond measure on the ballot should be removed, it's being abused, that's why our state's bonds have to pay such a high rate, because it's financially irresponsible. Whose going to bail us out? The federal government? HA! There's a small group of Republicans in the California government that has voted against every single budget for the last 2 decades or so. I used to think of them badly, now I side with them. I bet our elected officials are counting on the children of illegal immigrants to balance the budget.
If I could dedicate my life to a single cause, it would be to make California a Republican state. That would change everything. But with San Francisco, you can forget about that ever happening. But sometimes when I spend time in Orange County I think it's possible.
Well, fusion products escape the well. The magnetic field is only intended to confine electrons, not ions, and the electron well that accelerates the ions won't confine fusion products. Alpha particles will pop right out of the well and through the magnetic field, and hit a collection grid surrounding the polywell device in a p-Bll setup, creating DC current. In D/D fusion, you'd just put a water-jacket around the device and use the heat to turn a turbine.
You can't make a polywell bomb, because Polywell isn't a thermal fusion system, it's electric. In order to produce militarily useful kinetic/heat power, you would need something the size of a factory to produce the magnetic field, and gigantic capacitors to boot. And even then it's a not a runaway process like a fission-fusion bomb; it won't fuse fast enough to "detonate." And it would cost way too much.
Worse, there's excellent theoretical reason to think the idea cannot work at all, due to loss of energy from the beam ions to electrons (even if the beams can be formed and confined). This was pointed out years ago by Rider in his masters and Ph.D. theses at MIT (later turned into published papers), and never refuted by Bussard or coworkers in the peer reviewed literature. Other showstoppers also exist, such as very rapid degradation of the ion energy distribution due to ion-ion scattering. Again, this has not been refuted in the peer reviewed literature.
Of course we all lose our tempers now and then. Dean freely admits to being imperfect in this regard, which is why regulars to this establishment will generally be cut more slack than people who we don't know very well.
Still: behave like an adult, or go find somewhere else to play. Thanks.