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MSimon
Joined: 16 Jul 2007
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Location: Rockford, Illinois
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 Posted: Fri Nov 20, 2009 2:06 am Post subject: Fusion Will Never Work |
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http://europe.theoildrum.com/node/5929/
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An excellent critique of tokamaks. No mention of Polywell in the article. It does get a mention in the second comment (of 385 so far)
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scareduck
Joined: 17 Oct 2007
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| Posted: Fri Nov 20, 2009 4:02 pm Post subject: |
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| Dittmar is getting a lot of press lately, but there have been some substantial questions raised about his data indicating that he refuses to acknowledge shortcomings in his own work. There's a reason the peak oil doomers asked him to be on their site; he gives no hope at all, and I rather wonder if he's overlooking some particulars; many of the problems with nuclear technology are legal rather than technical. |
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MSimon
Joined: 16 Jul 2007
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Location: Rockford, Illinois
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| Posted: Fri Nov 20, 2009 4:31 pm Post subject: |
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| scareduck wrote: | | Dittmar is getting a lot of press lately, but there have been some substantial questions raised about his data indicating that he refuses to acknowledge shortcomings in his own work. There's a reason the peak oil doomers asked him to be on their site; he gives no hope at all, and I rather wonder if he's overlooking some particulars; many of the problems with nuclear technology are legal rather than technical. |
I would go further. They are ALL legal. The technology has its dangers. But it is pretty well proven we can handle those.
And if the nuke guys would just say: it will buy us 40 years until fusion is developed they would have a good selling point. Although with coal so abundant - why bother?
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TallDave
Joined: 25 Jul 2007
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| Posted: Fri Nov 20, 2009 4:49 pm Post subject: |
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| I found the various confusions about Polywell amusing. |
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MSimon
Joined: 16 Jul 2007
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| Posted: Fri Nov 20, 2009 4:56 pm Post subject: |
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| TallDave wrote: | | I found the various confusions about Polywell amusing. |
You might want to visit:
http://www.talk-polywell.org/bb/viewtopic.php?t=1610
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TheRadicalModerate
Joined: 04 Oct 2007
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Location: Austin, TX
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| Posted: Fri Nov 20, 2009 5:47 pm Post subject: |
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Wow, that whole thing is pretty grim. Two things jump out at me from the whole 4-part series:
First, he's taking really big swipes at the Red Book with minimal evidence but, if he's right, this is the most cogent case against fission investment that I've seen.
More relevant to fusion development, though, is his analysis of the near-impossibility of a self-sustaining tritium breeding cycle. If this is correct (and I'm in no position to offer a decent critique), then it seems to suggest the following syllogism:
1) Commercial D-T fusion is impossible due to tritium breeding problems.
2) D-T fusion is the only viable equilibrium fusion reaction.
3) Therefore, commercial equilibrium fusion is impossible.
Sure do hope that Rider is wrong... |
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MSimon
Joined: 16 Jul 2007
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| Posted: Fri Nov 20, 2009 6:43 pm Post subject: |
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| Quote: | | More relevant to fusion development, though, is his analysis of the near-impossibility of a self-sustaining tritium breeding cycle. |
I have looked into that and tend to agree. A tritium breeding cycle is theoretically possible. However the engineering margins are very slim. Generally you want a minimum theoretical margin of 2 to 1 for something like that (roughly the neutron economy in a fission plant). In theory the tritium cycle envisioned has a 10% margin making the design constraints very tight because you would like to generate an excess of tritium.
Polywell looks good even if pB11 doesn't work because the fallback is D-D. You get stuck with a thermal plant and high neutron fluxes but those disadvantages can be dealt with. And if you are willing to waste a lot of heat direct conversion might prove workable.
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scareduck
Joined: 17 Oct 2007
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| Posted: Fri Nov 20, 2009 7:50 pm Post subject: |
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| MSimon wrote: | | scareduck wrote: | | Dittmar is getting a lot of press lately, but there have been some substantial questions raised about his data indicating that he refuses to acknowledge shortcomings in his own work. There's a reason the peak oil doomers asked him to be on their site; he gives no hope at all, and I rather wonder if he's overlooking some particulars; many of the problems with nuclear technology are legal rather than technical. |
I would go further. They are ALL legal. |
All of them? I rather think the ability to run a fast breeder reactor economically is at this point wholly unproven. And that's a crucial thing if it's going to be held up as a potential solution to energy problems. |
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MSimon
Joined: 16 Jul 2007
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| Posted: Fri Nov 20, 2009 8:58 pm Post subject: |
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| scareduck wrote: | | MSimon wrote: | | scareduck wrote: | | Dittmar is getting a lot of press lately, but there have been some substantial questions raised about his data indicating that he refuses to acknowledge shortcomings in his own work. There's a reason the peak oil doomers asked him to be on their site; he gives no hope at all, and I rather wonder if he's overlooking some particulars; many of the problems with nuclear technology are legal rather than technical. |
I would go further. They are ALL legal. |
All of them? I rather think the ability to run a fast breeder reactor economically is at this point wholly unproven. And that's a crucial thing if it's going to be held up as a potential solution to energy problems. |
The only way to find out is to do some paper designs. Choose the best and build one. Although the control is twitchier we have much faster controls than we used to.
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williatw
Joined: 12 Oct 2009
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| Posted: Fri Nov 20, 2009 9:45 pm Post subject: |
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| I understand that Thorium reactors are being developed by India & China and are being looked at here. They would I understand work by breeding fissionable Uranium from Thorium. If you can breed Thorium to U, seems to me you could use them to breed Tritium from Lithium. Since your going to be developing the Thorium reactors anyway, you could use them to make your Tritium for the Tokomaks. So even if the Tokomaks don't make enough T to sustain their reactions independently, you could get them from the fission reactors that would be available anyway whether the commercial tokomaks are built or not. |
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kurt9
Joined: 15 Oct 2007
Posts: 296
Location: Portland, Oregon, USA
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| Posted: Fri Nov 20, 2009 10:57 pm Post subject: |
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Guys at Los Alamos told me that there was serious concern about breeding Tritium sustainably in order to support D-T fusion. What is the problem with D-D fusion?
Anyone ask Art Carlson about the issues raised in this paper? |
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D Tibbets
Joined: 26 Jun 2008
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| Posted: Fri Nov 20, 2009 11:27 pm Post subject: |
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| kurt9 wrote: | Guys at Los Alamos told me that there was serious concern about breeding Tritium sustainably in order to support D-T fusion. What is the problem with D-D fusion?
Anyone ask Art Carlson about the issues raised in this paper? |
I think that there is a strong consensus that tokamacs and other systems in thermodynamic equalibrium can only reach breakeven with the D-T reaction, and even that is still uncertain from a practical/ profitable perspective.
Dan Tibbets
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kurt9
Joined: 15 Oct 2007
Posts: 296
Location: Portland, Oregon, USA
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| Posted: Fri Nov 20, 2009 11:56 pm Post subject: |
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| D Tibbets wrote: | | kurt9 wrote: | Guys at Los Alamos told me that there was serious concern about breeding Tritium sustainably in order to support D-T fusion. What is the problem with D-D fusion?
Anyone ask Art Carlson about the issues raised in this paper? |
I think that there is a strong consensus that tokamacs and other systems in thermodynamic equalibrium can only reach breakeven with the D-T reaction, and even that is still uncertain from a practical/ profitable perspective.
Dan Tibbets |
Other than IEC polywell, which concepts do not operate in thermodynamic equilibrium? |
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kurt9
Joined: 15 Oct 2007
Posts: 296
Location: Portland, Oregon, USA
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| Posted: Sat Nov 21, 2009 12:00 am Post subject: |
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| MSimon wrote: | | Quote: | | More relevant to fusion development, though, is his analysis of the near-impossibility of a self-sustaining tritium breeding cycle. |
I have looked into that and tend to agree. A tritium breeding cycle is theoretically possible. However the engineering margins are very slim. Generally you want a minimum theoretical margin of 2 to 1 for something like that (roughly the neutron economy in a fission plant). In theory the tritium cycle envisioned has a 10% margin making the design constraints very tight because you would like to generate an excess of tritium.
Polywell looks good even if pB11 doesn't work because the fallback is D-D. You get stuck with a thermal plant and high neutron fluxes but those disadvantages can be dealt with. And if you are willing to waste a lot of heat direct conversion might prove workable. |
Would not the fission/fusion hybrid concept (LIFE) be the way to get around this problem? Certainly fission reactions are used to breed Tritium. |
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TheRadicalModerate
Joined: 04 Oct 2007
Posts: 89
Location: Austin, TX
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| Posted: Sat Nov 21, 2009 3:56 am Post subject: |
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| kurt9 wrote: | | Would not the fission/fusion hybrid concept (LIFE) be the way to get around this problem? Certainly fission reactions are used to breed Tritium. |
Most of Dittmar's objections would seem to apply to any D-T fusion reaction, so the hybrid approach will only work if the Li6 is receiving neutrons from fission, not fusion. I suspect that this is harder than you think, if only for the reason that most tritium is bred in heavy water reactors, using a D+n-->T reaction. (I'd kinda guess that it's vastly easier to extract the T from heavy water than it is from Li...)
Last edited by TheRadicalModerate on Sat Nov 21, 2009 1:03 pm; edited 1 time in total |
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