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#31
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"Christopher M. Jones" wrote:
Derek Lyons wrote: It's equally hard to see how progress is going to be made if you never progress beyond tons of small scale, limited goal experiments either. I find it utterly fascinating that anyone could describe projects costing hundreds of millions to billions of dollars as "small scale". Scale is determined by goals, not the size of the pile of dollars. We don't know just how well tokomaks are going to be work with any degree of certainty, and we won't know until we build one. I think that maybe, just maybe, there have been more than one or two tokamaks built over the years. I think you maybe meant to make a different point there. I meant "we don't know how suitable tokomaks are for long sustained burns and potential power extraction". D. -- Touch-twice life. Eat. Drink. Laugh. -Resolved: To be more temperate in my postings. Oct 5th, 2004 JDL |
#32
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"Paul F. Dietz" wrote:
The goal of all this is a commercially viable reactor. If tokamaks can't deliver on that goal, continuing with the development is, at some point, stupid, even if they are in a more advanced stage of development than the alternatives. Very true. But you and Christopher seems to claiming that we shouldn't perform the very experiment that will validate or invalidate tokomaks. Instead, we should be chasing after other systems less well developed that may or may not themselves work. D. -- Touch-twice life. Eat. Drink. Laugh. -Resolved: To be more temperate in my postings. Oct 5th, 2004 JDL |
#33
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Derek Lyons wrote:
"Paul F. Dietz" wrote: The goal of all this is a commercially viable reactor. If tokamaks can't deliver on that goal, continuing with the development is, at some point, stupid, even if they are in a more advanced stage of development than the alternatives. Very true. But you and Christopher seems to claiming that we shouldn't perform the very experiment that will validate or invalidate tokomaks. Instead, we should be chasing after other systems less well developed that may or may not themselves work. Derek, what you are ignoring is that we already have a great deal of experience with tokamaks. And we already have detailed engineering designs of tokamak power reactors (PULSAR, STARLITE, the ARIES series of designs). These designs have been heavily cost optimized. And what do these detailed studies reveal? That getting tokamaks to be competitive is going to be difficult. They need advanced physics (better than what will be demonstrated in ITER, the current conception of which doesn't even reach ignition, but is planned to operate at Q ~ 10), they need to be big (2 GW(e)) and even then they're only just competitive. The tokamak concept is just inherently marginal, due to its topology, size, and its inefficient use of magnetic fields. Paul |
#34
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Derek Lyons wrote:
"Christopher M. Jones" wrote: Derek Lyons wrote: No, it's a fact. Regardless of the machine chosen, you'll eventually have to steel your courage, build a full size one, and hope. Christopher on the other hand is advocating continuing small experiments in the hope that one will produce cheap results. I asked you kindly to not grossly mischaracterize my position. Perhaps that was too much to ask of you, Derek? That's the position that you seem to be espousing. It is not and never has been. I advocate cheaper experiments because they seem to explore more useful parameter spaces, because they provide more science return for their cost, and because they are the appropriate direction to take at this time, in my estimation. Moreover, as I said, characterizing state of the art, billion dollar experiments as "small" or "cheap" is erroneous at best and disingenuous at worst. You have things completely backward, I wish to explore the best routes to commercial fusion power sooner and more efficiently while ITER purposes to gamble the majority of fusion research funding on a questionable and outdated design. |
#35
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Derek Lyons wrote:
"Paul F. Dietz" wrote: The goal of all this is a commercially viable reactor. If tokamaks can't deliver on that goal, continuing with the development is, at some point, stupid, even if they are in a more advanced stage of development than the alternatives. Very true. But you and Christopher seems to claiming that we shouldn't perform the very experiment that will validate or invalidate tokomaks. Instead, we should be chasing after other systems less well developed that may or may not themselves work. I'm sorry Derek, but you appear to be grossly in error on many points in your post. Firstly, you misdescribe ITER as "the very experiment" when in reality it is merely one experiment. Should we not expend our efforts on the best experiment rather than simply the most ambitious or expensive experiment? Take a look at page 7 of this summary: http://fire.pppl.gov/ARIES_FIRE_ITER_nrc.pdf Or read this summary of the Fusion Ignition Research Experiment (FIRE) he http://fire.pppl.gov/bpac_fire_091802f.pdf Then tell me why ITER is the best choice to explore fusion reactor designs? Secondly, you claim that I am advocating chasing after "less well developed" systems, when the opposite is the case. FIRE represents less extrapolation from currently explored plasma regimes, period. Thirdly, I am not advocating abandoning tokamak designs, FIRE is precisely a tokamak design and I am in favor of building it. I do think we ought to be exploring other design alternatives at a level of funding appropriate for pure science research (i.e. much less than what we spend on tokamaks but still significant), but that's a separate issue. Fourthly, ITER is not an expriment capable of validating or invalidating the tokamak design for fusion power production. No individual experiment can be, though results can be suggestive. Since ITER does not explore the areas of most interest with regard to plasma conditions in power production fusion reactor designs, it is particularly ill suited to rule in or rule out such designs. My estimation (and I admit to being far from an expert in these matters) is that ITER is more risky, will provide less useful data, and will be much more expensive than alternatives such as FIRE. Which is why I believe ITER to be a waste of money. If it were the only option on the table it might, perhaps, be worth building, but it is not. We have better options now, we need to exploit them. |
#36
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I wrote:
And what do these detailed studies reveal? That getting tokamaks to be competitive is going to be difficult. They need advanced physics (better than what will be demonstrated in ITER, the current conception of which doesn't even reach ignition, but is planned to operate at Q ~ 10), they need to be big (2 GW(e)) and even then they're only just competitive. The tokamak concept is just inherently marginal, due to its topology, size, and its inefficient use of magnetic fields. To expand on this further: they are only possibly just competitive for generation of electric power, when compared against other *current* technologies. For other uses of energy, such as in transportation fuels or smelting of ores, they are even less competitive. To displace fossil fuels in those markets requires even cheaper energy. Moreover, 40+ years from now, when tokamak-based reactors might come onto the market, the competition for electric power will not have stood still. Renewables and fission reactors will have advanced down their learning curves (renewables particularly so), and will also be much less risky to potential investors. What this all means is that for fusion to be taken seriously, it has to be more than competitive, it has to decisively beat the current alternatives. Tokamaks don't. Paul |
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