Talk:Fusion power/Archive 1

Archive 1

Archive 2

Archive 3

Will ITER displace other research into fission?

Someone writes "The proposed ITER would use magnetic confinement, effectively killing off research into the inertial design regardless of its merits."

What is this supposed to mean? Inertial fusion designs won't suddenly die off due to some ITER conspiracy. I don't get why someone feels like adding funding to one type of research will kill off all other types. [[RK]]

Because:

1. they compete for the exact same source of funds.
2. that's what happens when one project gets the lion's share of the brains and money (a well-known dynamic in computer science, see Worse Is Better).
3. that's what the people working on the inertial designs think about ITER.

Given that currently the biggest researcher in Inertial Confinement Fusion is the US military, I doubt ICF is in any danger of losing funding. ITER is based on magnetic confinement research, primarily done in universities and aimed at producing power for civil uses. ICF is based in military labs attempting to create the conditions present during a thermonuclear explosion in order to better understand the workings of fusion bombs (see Stockpile_stewardship). So it's highly unlikely that MCF will draw substantial funds away from ICF.

Do Generation and Extraction of Energy (by and from fission reactions) Differ?

Someone else writes:

There are three types of break-even points: being able to generate as much energy from the reaction as you put in, being able to extract as much energy from the reaction as you put in, and being able to extract as much money from the system as you put in.

What's the difference between the first two points? I'll leave this as it is in the hope that the original writer will correct it. -- user:Heron

I'm not the original poster, but when I read it it seemed clear enough. By "extract ... energy" it appears that being able to utilize the energy is the goal. If you're between the "first two" break-even points, the reaction is outputting more total energy than you have to put in to start and maintain the reaction, but a lot of it is released as waste heat instead of running light bulbs and textile factories; thus you're losing on usable energy until you hit the second break-even point. (But IANANP.) --Brion

IANA* : wow, I didn't know that this acronym was to be found outside the Straight Dope Message Board. - user:Montrealais

You need to get out more, amiko. :) IANA* is to be found all over usenet. --Brion 03:54 Sep 10, 2002 (UTC)

For those (like me) who don't frequent usenet, I'm now told that IANA* is "I am not a...", as in IANAL "I am not a lawyer" or IANANP "I am not a nuclear physicist". They were new to me! Andrewa 19:29 3 Jul 2003 (UTC)

Risks of fission belong in the fission article

Deleted two things from the article - an sentence about the risks of meltdown or otherwise in modern fission designs (didn't really belong)... Robert Merkel 01:37, 7 Sep 2003 (UTC)

Do fission and fusion use up their reactants? What is 'reduction of radioactivity?'

...and a paragraph about the claim that fission is somehow more environmentally sound because it "uses up" the earth's net supply of radioactive material rather than creating more radioactive material. This argument is a) completely nonsensical and b) unattributed. Unless it is a common claim made by some group of importance, it doesn't belong here. Robert Merkel 01:37, 7 Sep 2003 (UTC)

The claim isn't nonsensical, what is nonsensical is all the bad science that people believe and which makes it sound incredible. NPOV is pretty hard to achieve here, and I won't try to put the argument back in. Interested if someone else wants to try.

It is a fact that, long term, the current fission plants are making the world less radioactive, rather than more radioactive, and a surprising one to many people. The cross-over point to achieve this is about three thousand years maximum... that's a worst case of a PWR using no recovery of transuranics, just burying the fuel elements whole as in the Swedish program or Yucca Mountain. An FBR can in theory get the figure down to about 70 years using maximum recycling of transuranics. Finding out what is practical is what the French are doing with Phénix. Again, these figures are incredible to most people, which is a shame. Andrewa 15:51, 5 Mar 2004 (UTC)

Andrewa, how does that work? Less radioactive materials are made into more radioactive ones, aren't they? Even if the net radioactivity of the world is decreased because some radioactive material is converted to energy, there will be regions of much higher radioactivity than would naturally occur and the associated risks of contamination through dispersal of this material (which would not be dispersed homogenously throughout the world should that happen, of course). Am I missing the point?

Which bad science are you refering to, by the way? Mr. Jones 13:22, 7 Mar 2004 (UTC)

Less radioactive materials are made into more radioactive ones, aren't they?

No. What we do is take lots of somewhat-radioactive material and process it into a much smaller amount of slightly more radioactive material. Then we "burn" it in a reactor, releasing most of the radiocativity (which we use, indirectly, for power) and are left with highly radioactive "ash". After a period of time, when the radioactivity of the ash burns off, the net result is less neutrons in the world.

That said the statement is still largely useless overall. If we just left the stuff where it is, we wouldn't have anything to worry about.

Maury 00:42, 26 Oct 2004 (UTC)

New Diagram Seeking Review

I made a diagram displaying the renewability of fusion by products by incorporating them into other fusion reactions. I would like somebody to review the diagram to make sure there isnt any mistakes/impossibilities. If there is simply mistakes, i would enjoy fixing them myself, but if its impossible dont jump to add it. Also if you are an expert in the field and have reviewed it and think its worthy of the article, ADD IT BECAUSE I DONT KNOW HOW. the image is: (html code version) <a href="http://img516.imageshack.us/my.php?image=model1cf8.png" target="_blank"><img src="http://img516.imageshack.us/img516/6029/model1cf8.th.png" border="0" alt="Free Image Hosting at www.ImageShack.us" /></a>

Request for Statistics from Anonymous user

look, if you re going to talk about waste levels and the environment, why dont you put some numebrs in there?

1. How much energy does it take to extract deuterium from water 2. How much energy does it take to extract tritium from wherever it comes from 3. If the tokamak irradiated its shell, how long will it be irradiated for? And where will it be stored while it 'cools down'? And how much energy will that take? 4. You say it must cost less money than the money it would bring in. well, currently, how much money does it take to build an experimental reactor. how much have the costs changed over time? How has the energy produced changed over time? 5. more detail about potential accidents.

6. 'government regulation' is not the problem with fission. there is a reason government regulates it, and that is because it is deadly and dangerous, and the industry has been careless. the science geeks running this type of project dont care about that because 1. they can buy a nice house far away from any nuke plant, or 2. they have let their work go to their head and are more concerned with fame than with providing clean energy, or 3. they are extremely conservative and blame everything on 'crazy liberals' instead of analyzing the issues objectively, or 4. they are just plain stupid.

it is nice to pretend that you live in a world where you dont have to clean up your own poo. but someone always does, and it always costs money. if the fusion people are going to stick their heads in the sand about this issue, like they did with fission, then fusion is doomed. if they applied as much analysis and brainstorming to the environemtnal and health problems as they do to getting themselves published and doing 'k3wl stuff', maybe things would be different.

68.14.170.144 (the origin of such vignettes as this, but also some useful edits Mr. Jones 13:22, 7 Mar 2004 (UTC))

Your hypothesis that no scientists care about the safety of people and only care about money is completely false. If this were true we would've been dead a LONG time ago.

Although the original questions were posed in a highly NPOV way, the questions themselves are valid enough.

1) D is already extracted in large quantities for the CANDU reactors in Canada. The process basically consists of boiling water. The amount currently extracted is more than what is needed to run all of the US on fusion power. So in one way of looking at it, the answer is "none".

2) T is produced in the reactor itself, via reactions with a surrounding "blanket" of lithium. About 100kg of Li will be "used up" per year in this process in a baseline 1GWh reactor. Li is currently supplied as a byproduct of some mining processes (and thus, once again, is energy-free) and costs about $15/kg on the open market, so about $20k a year for a reactor. However a lot more Li is needed in the blanket than is used up, about $15 million. This is currently baselined at about 15% of the cost of a reactor core (that is, excluding the buildings, waste, etc). Most of this would be re-used in new reactors.

The two items combined above are, if I do the math right, require about 100 times less energy than shipping the same energy amount of coal. Moreover, due to the "density" and weight, fusion fuel is about 10 times cheaper to ship (because it's about 10 times the power to weight).

3) Using normal "low activity" stainless steels, it remains "hot" for about 15 years, and "warm" for about 150. After 300 it is the same radioactivity as coal ash, and considerably less that that of the average brick house. Using other materials, notably carbon fibre composites, the numbers are all reduced by about an order of magnitude, so 1.5, 15 and 30. We've already stored nuclear materials without incident for longer than this. Morover the materials in question are "locally radioactive" only, and don't have to be buried, thereby almost elimintating the risk of water table leakage and such. Radioactivity is exothermic so it requires no energy to store it (I mean, duh), and models generally dump the reactor core on-site for zero transport costs.

4) This is a specious argument. No one knows how much it will cost in the future, how much electricity will sell for, or how much fossil fuels will cost. Generally the costs are linear with reactor size (the exception being the rediculously overcost Z Machine). The energy produced over time has increased infinity times.

5) the worst-case scenario for a fusion reactor is a complete venting of the tritium storage, the only gasseous radioactive material. Given a baseline 1GWh reactor, the load would be less than 1 curie at the station fence. That's the _worst_case_, and would require seriously rediculous scenarios (destruction of the contaiment building, complete release of tritium storage). The next-to-worse scenario is a lithium fire with complete release to the the air, which would release a smaller dose of tritium. Both combined would still be below the 1 curie limit, a dosage so low you would likely not even notice it (LD 50 is 250 rad). Mechanical failure, a complete magnet drop for instance, would be dangerious to on-site personel, but no more so than existing risks such as a turbine sheding a blade, which happens time to time.

6) This is the most rediculous of the "questions", although is is not posed as one. Contrary to your elusions, nuclear power has been one of the safest forms of power ever invented.

If we stick with that super-dangerous fission power for a moment, it is arguably the safest form of power per-kWh ever in history. There have been exactly two major accidents in all of time, Three Mile Island and Chernobyl. In the former the only release of radioactivity was deliberate, the containment building was never challenged. In the later, there was no containment building (money, not geeks). The former resulted in no injuries and no long-term issues at all. In the later 31 people died, more were injured, and more will get cancer as a result. The last number is highly contentious, varying from 40 to 24000 depending on the source. Additional "incidents", generally due to disposed medical equipment, add 2 to 4 a year.

So now let's compare this with coal. Coal kills many miners a year, the first number I came across is 7000 a year in China alone. Deaths due to coal pollution are much harder to judge, but again the first number I came across is 10000 a year. Google it yourself. So coal power kills more people in two years than the entire history of fission power.

And, given the systems, it's entirely reasonable to suggest that fusion power would be extremely safe compared to either. Even in the worst case release, no one offsite would receive a dose that would be even dangerous, let alone deadly. On-site risks are identical to those in existing power plants -- turbine failures, pipe ruptures, etc.

BTW, the vast majority of nuclear workers live near the plants, of course. Driving is dangerous.

There is ever reason to suggest that fusion power would have the least enviornmental impact of any energy source to date. Whether or not it will ever be economic is another issue entitely. However, given the first statement, I can't imagine any reason that someone would possibly think it's not worth giving it a try.

(NPOV ON)So maybe if you took 15 minutes to learn about the topic instead of reading up on your 'kewl stuff', you wouldn't have to ask such basic questions and look like such an ass. Geeks come up with new ideas, like the wiki, generally because they're better than old ideas. Idiots come up with idiotic ideas, generally because they're lazy.(NPOV OFF)

Maury 00:42, 26 Oct 2004 (UTC)

Cross-Over Point?

"... the point where the system is generating enough money to pay for itself. This last goal looks to be at least 50 years off at any given point in time."

Not entirely sure what this sentence means, therefore, I don't know how to correct it. If a goal "looks to be 50 years off at any given point in time," that goal has been 50 years away for the past 5 billion years. I think what the writer may have meant is 50 years away from the present, but...

If you're looking for the full original context, it's the second paragraph under "Power Plant Design." StellarFury 21:42, 9 Aug 2004 (UTC)

Explanation: research on large-scale fusion reactors is hugely expensive, but its proponents believe that continuing research is important, and consequently the fusion community gained themselves something of a reputation for making over-optimistic claims about how soon the technology could be implemented, if only the politicians would cough up the cash for the next project. After a while it began to be suspected that perhaps these forecasts were driven by the need to secure support for funding rather than by the science, and that perhaps the people making these forecasts knew that there was no realistic likelihood of them being met: someone always seemed to be telling the the public that fusion power was "just around the corner", and it never was.

This led to a widespread joke told by physicists and engineers, that "practical fusion power is 40 years away ... and always will be".

The idea behind the "constant 40 years" (or whatever other timescale one chose to insert) was that these timing estimates seemed to be based not so much on scientific knowledge but on politics: Use a figure that's too far away and you won't get your multi-billion-dollar funding: make it too small and you have to show significant progress. Forty years is close enough to allow an economic case, but not so close that one has to be seen to be passing significant milestones. So, commercial fusion power stayed "forty years away" in the 1950's, 1960's 1970's and 1980's.

When the 1990s came around, people began to get a bit more pessimistic about the claims, and a popular (slightly more jaundiced) variant of the joke became "Fusion is the power source of the future ... and always will be".

A recent New Scientist editorial [1] quotes an unnamed senior scientist as explaining "We think it's going to work. We have to, or the politicians wouldn't give us the money." ErkDemon 19:30, 13 July 2007 (UTC)

Moving heating here

This doesn't really belong here, it applies only to magnetic fusion systems. Inertial, pinch and electrostatic systems self-heat. I'll move it into the correct article later.

(snip) Moved to tokamak. - mako 01:09, 28 June 2006 (UTC)

Chain reaction

I don't think the line "No possibility of nuclear runaway, as there is no chain reaction" is accurate. An ignited fusion reaction IS a chain reaction. D+T=high energy He which further heats the plasma increasing the fusion reaction rate. This is a kind of chain reaction no? Not all chain reactions need involve only neutrons I should think. Obviously fusion reactions are inherently safe, the plasma quenches at the slightest purturbation, but I dont think "because there is no chain reaction" is one of those reasons. Thoughts? --Deglr6328 08:10, 13 Dec 2004 (UTC)

no comments....removed mention.--Deglr6328 08:56, 29 Dec 2004 (UTC)

It's safe because there's only enough fuel in the vacuum vessel for the fusion reaction to continue for a matter of seconds. Dan100 16:57, Jan 16, 2005 (UTC)

Censorship of Critical Fusion History in Wikipedia

Someone touting himself as a "skeptic" deleted a critical historical reference with scanned in images of original source material so that he could express his contempt for the person who provided this material: me. This sort of ad hominem attack might be little more than a demonstration of hypocrisy in such a supposed "skeptic" were it not for the fact that the original source material is from a founder of the US fusion energy program claiming that the tokamak program was never "real" -- that it was, from the outset, a budgetary vehicle promoted for its political appeal. As such it must not be excluded from the Wikipedia article on fusion.

Jim Bowery 20:27, 28 Dec 2004 (UTC)

I don't know if "touting" is an apt adjective but yes, I am in general "a skepitc" and no, removal of changes you made to an article isn't always "censorship". I removed the link to your own website because it is a geocities site and linking to geocities sites as being authoritative is generally a bad idea due to the fact that anyone can post anything they want as being fact(just like linking to a wikipedia article in wiki's curent form as being authoritative is simillarly discouraged for the same reasons). Secondly, I removed the refrence because in absolutely no way does the letter demonstrate that politics is "a major barrier to development of fusion power" (a borderline absurd claim in it's own right). Thirdly, I removed the link becasue after looking at your site and some other sources pertaining to you I came to the conlusion that you, nor your ideas are trustworthy. I present as corroboration of this view the following materials writen by you: you seem to think there is a connection between UFO's and federal building bomber Timothy McVeigh [2], you harbor bizzare pseudoscientific ideas about genetics and biology [3], your essay on why you think "Immigration Causes Autism" appears to be thinly veiled racism [4] (and weather you are aware of it or not racists endorse your views [5]), you seem to think the cydonia Mars face is of artificial origin [6], you are rabidly anti-semetic [7] as others have noted [8]. In conclusion, as many others have already noted [9] your abounding kookery I will stop here and only say that your edits will be very closely monitored here on wikipedia by myself and others. Oh look, it appears as if you've already begun your pogrom against Jews and feminism here too [10], [11]. lovely. --Deglr6328 21:41, 28 Dec 2004 (UTC)

The comment in the article history removing the link to the images of the critical historical documents was: "link to a jim bowery geocities page? niiiice...the guy is a total kook and anyway that page provides virtually no support of the theory stated". This is primarily an ad hominem attack, just as is your response here. The fact that you provide no clear identifying information with your username, combined with the fact that you call yourself a "skeptic" places a burden on you to cease your ad hominem attacks and start dealing with content. BTW: I do encourage people to look over the entirety of my website. I make no bones about it containing my perspectives, some speculative, about a great many things. The scanned images are not speculative or perspective -- they are historical data. Jim Bowery 22:00, 28 Dec 2004 (UTC)

Oh shall I post my home address and phone number then to satisfy your demand of "identifying information"?? bizarro... Anyway what I was essentially saying here is that I don't trust that those scans have been unaltered, by you, or whoever. An encyclopedua article should represent the consensus of thought on a particular topic at a certain time, there needs to be more evidence for a claim than a mere linking to some scanned pages of type on a personal website if something is to be presented as fact. There should be OTHER sources of this document somewhere out there if its real and actually important.--Deglr6328 22:40, 28 Dec 2004 (UTC)

If the document is real, how can it be unimportant? One of the founders of the tokamak program saying this -- the primary recipient of fusion funding for decades was not "real"? Come now, anonymous one, surely you can do better. For instance, you could have pointed out that, in the cover page to the scanned images I gave Robert Johnson, the inventor of the magnetic ink numbers appearing on all checks as the person who handed me the letter -- and that this is one source of credible cross-verification. You don't strike me as a skeptic. You strike me as someone who dislikes my perspectives, speculations and values and wants therefore to act not as a skeptic but as an advocate against clearly verifiable facts about me that would tend to lend me credibility. As you point out, you are far from alone but numbers make primarily for political correctness. Jim Bowery 22:53, 28 Dec 2004 (UTC)

Wikipedia does not publish original research, which includes novel claims published only on the web site of a particular individual. This is not a reflection on the merit of those claims — Wikipedia is simply not the proper venue. We have to stick to material already well-established in traditionally reviewed publications, sorry. —Steven G. Johnson 01:04, Dec 29, 2004 (UTC)

There is a real difference between "original research" and "primary documents". There simply is no venue for a primary document of the type Bowery hosts on his website. Claiming that the document is fabricated strikes me as an act of extreme paranoia. This guy is someone that gave congressional testimony-not some UFO cult leader.

Sorry, somebody posting something on a Geocities page is not sufficiently credible to be on Wikipedia. In any case, even if accurate fusion researchers seem to like to beat each other's designs up all the damn time. Singling out one person's beating up without context is highly inappropriate. --Robert Merkel 06:05, 29 Dec 2004 (UTC)

The whole point is that an originator of the US Tokamak program is beating up on his own design and he's not the only originator to do so. Robert Hirsch, the head of the original Tokamak program, and Bussard's colleague has also come out against it. It is simply not reasonable to characterize this as just another sibling rivalry. These guys are the fathers of the US Tokamak program and one of them goes beyond saying it won't work to saying that it was never even expected to work except as a budgetary vehicle for other concepts. Criticizing the service provider that is vending these primary documents has nothing to do with it. They would be no more or less credible if they were vended by a dedicated web site. Your only objection to them seems to be that they are vended by my website, regardless of the hosting service. The question simply reduces to whether these primary documents are fabricated or not and you are implying that it is plausible that I have fabricated them. Are you not? Jim Bowery 07:41, 29 Dec 2004 (UTC)

The stuff from Bussard aside, it is rather pollyannish to discussion fusion energy with no references to the controversy around fusion power. There is a history here that needs to be discussed for this article to be meaningful _and_ the simple fact is that some non-mainstream characters are involved at times.

Gosh, editing pages on "swinging" AND fusion power[12] Mr. 131.191.88.246?? I wonder who you could be!? Jim Bowery is that you!?! Goodness you're [13] so wily and scheming! No one here ever said said anything about not including controverisal aspects of the potential of fusion power. We did say, however, that we need reputable sources for that information, and geocities sites don't cut it, sorry. --Deglr6328 05:31, 30 Dec 2004 (UTC)

This is the aonymous Mr. 131.191.88.246. Now, if you check this IP address, you will find it isn't and cannot be the same as Baldrson's. Anyhow, the issue here isn't how information is broadcasted, but who gets the right to introduce primary sources. The US congress thought Baldrson was competent to submit testimony(just check the Congressional Record). In this case, Baldrson has a copy of a primary source document. I see no reason why that primary document is "original research". Don't blow smoke about the press here-the press isn't concerned about these kinds of issues(they exist to serve advertisers).

No you're not. You're participating in writing away highly disruptive and highly relevant history about fusion power, you're quite happy to do it and you're demonstrating your total lack of regard for any semblance of honesty by making reference to an anonymous person's editing of an article on "swinging". I guess you hope some idiots would think that maybe I'm a "swinger" that reflects poorly on my credibility or something. Your argument about something being hosted on a "geocities" site is equally specious. The bottom line is the little group of nothing-better-to-dos-with-their-times doesn't like the relevant facts. This is just the sort of petty politicization that has held back fusion technology from practical breakthroughs. Jim Bowery

*Yawn* --Deglr6328 04:55, 8 Jan 2005 (UTC)

So now you are sleepy, eh? I guess that's what happens when one wires its alarm clock to Wikipedia...

A discussion on slashdot regarding this talk page. — Ævar Arnfjörð Bjarmason 05:41, 2005 Jan 8 (UTC)

This is a link to the statements Hirsch made about Tokamak-which tend to support the authenticity of Bussard letter. [14]

Overhaul

This article was full of POV and unsubstantiated claims (both ways), so I've cleaned it up. I should confess to being possibly biased, as I previously worked at JET. Dan100 17:45, Jan 16, 2005 (UTC)

I agree with the overall sentiment of your edits to the article, however I have a few objections/questions to some of your removals. Such as, why did you remove:"No afterheat cooling problem in case of an accidental loss of coolant"? This is true is it not? Of course the heat capacity of a few torr of H in a vacuum vessel is rather paltry but I don't think that negates the the statement.

• It's linked to the 'no-meltdown' thing - in the event of any system failure, all that's needed is for the fuel supply to be shut off and the plasma extinguishes in seconds. Further, the actual energy in the plasma in the vessel isn't that great compared to the mass of the structure of the machine - JET has lost confinement several times at full power, the machine moves a bit (which is quite impressive when you remember it weighs over 5,000t) but it's all within design parameters.

ok. good enough. But I'd like to add this to the article.

Also: "or that the radioactive waste can be kept to these levels. It is possible that fusion advocates are making some of the same mistakes in creating unrealistic economic projections that fission advocates have made in the past." I think these are entirely reasonable criticisms really. Maybe wording needs to be changed but I too sometimes remain unconvinced of the "extremely cheap power" promise. After all, I think we can agree that the instument which will likely be required to sustain a fusion power reactor will require high technological mastery and be rather pricy.

• It's probably the commonest criticism. It's a bit unfair to revisit 'the sins of the father' on the son. Economic projections are much tamer now. Development costs are actually very low - for example the development cost of ITER is only about $10bn, which, when compared to the annual revenue of say the U.S's energy companies, isn't a big hit. I don't recall hearing much about "extrememly cheap power". Certainly all the JET promo material talks about 'plentiful fuels' and 'a vast, new source of energy', but carefully avoids discussing cost!

ok.

And: "....lithium fire or the accidental release of magnetic energy." The part about the "magnetic energy release" is rather idiotic but the Li fire hazard seems a legit concern to me.

Magnetic energy release isn't as kooky as it sounds. What they mean is that the superconducting magnets overheat. If the temperature rises above 4K, the magnets are no longer superconducting, ie they are resistive. Thus the massive current generates heat, raising the coolant temperature more, meaning more resistance, more heat, etc. Since the magnets are huge and generate a magnetic field on the order 10T, a "meltdown" of the magnets means several megajoules of energy is released in a few seconds, an effect that has been compared a lightning strike. This could lead to structural failure of nearby components, or heating of an adjacent magnet, resulting in more of the same. 136.159.43.12 20:20, 17 March 2006 (UTC)

It's not even referring to that. Magnetic energy release is quite a serious concern. There are 'vertical displacement events', even in JET, which send the entire apparatus propeled a bit upwards. This is essentially the energy in the magnetic field (proportional to B^2 locally) getting converted into a strong electric field and blasting some part of the reactor. A big problem.Danielfong 02:49, 20 March 2006 (UTC)

• Lithium is very reactive, yes. However the blanket has a low surface area to volume ratio - it's not as dangerous as, say, the powder form. Further, it's under vacuum, so there's no oxidant present. Of course it is a real risk, but it has been 'designed-out' of the system.

good I'll add this.

Another: "We have been capable of reaching this break-even point for over a decade." I think I added this. Is it not true that JET reached breakeven in 1994 with some DT shots?

• No, JET reached only 0.65 energy in/out ratio in 1997. None of the currently existing tokamaks are capable of reaching break-even.

hm. ok

I have a question about this. Japan's official JT-60 page claims to have borken breakeven. They've published papers and so forth. Are they talking only about the reactive regions or the entire machine? I've modded the JET and JT-60 pages according to this, but if it's incorrect, I should like to mod back quickly.Danielfong 14:35, 3 March 2006 (UTC)

The Japanese tokamak JT-60 does not use Tritium (the fuel for a working fusion reactor) due to the associated licencing and safety issues. All of their shots have used Deuterium only. Their "break even" claim is based on extrapolation of the temperatures achieved with D shots, that is, taking the plasma temperature of the D plasma and pretending that it was a 50/50 D/T mix shows that JT-60 would reach breakeven if DT was used instead of D only. However, there are various issues dealing with the method that the Japanese use to extrapolate the DT burn vs. D only, the Americans use a different method which implies that JT-60 is just below breakeven (I will try and find the paper saying this). 136.159.209.19 02:40, 17 March 2006 (UTC)

Just one more: "In a fusion reactor intended to produce power it would be highly advantageous to achieve a reaction in the ignition regime, though it is not clear that it is absolutely required for economical operation." Don't know what the objection is here...

• I honestly don't know what that means. The reaction does have to be 'self-heating', or the system will still be a net user of energy, not a producer.

Right, it does have to be self heating but it does not have to necessarily get 100% of its heating power from the fusion reaction. For instance a reactor at Q=2 will be putting out 2X more energy than is going in (over breakeven) but may not necessarily be ignited.

Also, no need to remove the fictional appearances mention is there? I mean it's clearly labeled as fictional, I think its at least mildly interesting.

• I just thought it was bit off-topic. I'm sure there's been lots of fictional references - the science dates from the 1940s, after all - but it's not hugely relevant, it's not really significant that it's been mentioned. It's no big deal though.

ok.

As a fellow worker in the fusion research field(heh) (I work here [15]) I share the desire to promote fusion as a solution to power generation needs but I feel some of the above edits have stepped into the realm of POV. Anyway, perhaps you can clear something up for me. Just what is a "vertical displacement event"? I have heard of these happening in the early days of JET and stories that they are events where for some reason the plasma magnetic field "bucks" against the field of the external coils and has lifted the whole lot up in the air a couple inches!! On the other hand, from what I've read myself, all I can tell it may be is a displacement of the high density plasma in the vessel with no real notable events at all really. --Deglr6328 07:58, 21 Jan 2005 (UTC)

• POV is always a difficult topic. While a POV may be true in a very small way, does that always warrant inclusion in an article? But perhaps it would be best to return my edits, and you/me/anyone write rebuttal similar to mine above. Dan100 07:55, Jan 26, 2005 (UTC)

Energie extraction from tokamak

How dow they extract the energy from the fusion going on in a tokamak to finally power my TV at home? Is this done in the regular "heating water and moving a steam turbine" process? Thanks, --Abdull 6 July 2005 15:56 (UTC)

Yes. (Hypothetically.) The fusion reaction releases high energy neutrons. These are absorbed in the blanket of lithium and other stuff, which heats up. A coolant is circulated through the blanket. The coolant goes to a heat exchanger and the rest is like any other electrical plant in the world. Art Carlson 2005 July 6 16:07 (UTC)

I always felt this is funny. Here we are, using the most powerful computers and other technologies human kind has to offer, spending decades to tackle the problem of magnetic confinement, and ultimately the power is still generated by an ancient turbine. Albester 10:44, 16 August 2006 (UTC)

However, note the mention of aneutronic fusion, where this would not be the case. However, aneutronic fusion is even more far away than a plant based on D-T fusion.--Robert Merkel 7 July 2005 02:04 (UTC)

What matter, exactly, is converted to energy?

The article gets almost all the way by saying ...they may fuse to a single nucleus with a slightly smaller mass than the sum of the two reactant nuclei. The difference in mass is released as energy, following the relationship E = mc².

What particles, exactly, are converted to energy? Can someone explain this right in that sentence? Tempshill 7 July 2005 23:58 (UTC)

No particles are converted. Two protons and three neutrons are in a lower energy state as ⁴He and n, than as D and T. A watch that has run down is in a lower energy state than when it was wound up, and will weigh less. The only thing unique about nuclear is that these energy differences are enough to actually be weighed. pstudier 2005 July 8 00:52 (UTC)

Quantifying environmental issues

The section on "Safety and environmental issues" is very enlightening, and appears to rebut some of the claims Greenpeace has made about the environmental dangers of Tokomak fusion power. However, it would be nice if some rough idea of numbers could be provided. How much radioactive material would be released in the worst-case scenario (a bomb under the torus)? How much tritium would be released per joule? What's the half-life of radioactive stainless steel, and how much of it would have to be disposed of on decomissioning a fusion reactor? Even if the error bars were an order of magnitude or more wide, some sort of idea of the quantities would be better than none at all. — ciphergoth 09:00, August 31, 2005 (UTC)

Rather than a bomb inside (there isn't going to be a parking garage underneath), I think a more realistic worse case is an airplane flying into the torus. The ITER page says the torus contains 1/10 gram of deuterium and tritium at any one time. There are plans for a 25 gram production/storage facility on site. Note that tritium isn't dangerous unless inhaled/ingested/used in nuclear weapons. The ITER waste page [16] says that "Estimates of ITER material masses show that about 30,000 t of material will be radioactive at shutdown, and that 80% of that can be cleared within 100 years." Lots more on that page. --noösfractal 09:45, 31 August 2005 (UTC)

How much of the information on [this page] regarding radioactive waste and nuclear weapons is actually true? Jibjibjib 08:05, 22 January 2006 (UTC)

Most of it is sort-of correct. ITER will use large amounts of electricity (though negligible in terms of France's total electricity use), will not generate electricity in itself, and will result in the creation of some radioactive waste, you could use the money to build offshore turbines insteadn. Fusion power will be used to breed tritium (which is used in nuclear weapons) and could theoretically be used to breed plutonium (again, which is used in nuclear weapons), with some difficulty. But it misses the point completely. --Robert Merkel 23:41, 22 January 2006 (UTC)

End of the Economics Section

We must however note that current economy can be in a "local minimum" of oil age, where cheapness of oil is determined by available infrastructure and experience. It is not sensible to compare the price of oil industry with already build ports, pipelines and oil rigs to completely pioneering technology where the effect of scale is not visible yet. We are in the position of a lazy person who has basic food at hand so does not have to seek for better, althought he knows that it is probably somewhere.

Safe and standard fusion plant could increase availability of energy 10 or maybe even 100 fold. With such energy we could probably get unlimited access to mineral resources getting it from ordinary earth crust if necessary [1]. We could desalinate sea water and irrigate whatever we need. It would have positive impact on environment comparing to fossil energy (no toxic and CO2 emmision) and renewable energy which has to occupy large land areas.

This doesn't sound right at all. If it isn't omitted, it ought to be condensed or changed completely. Most of it is superfluous and speculative, and the personal pronouns "We are..." make it sound very unprofessional. I did remove the entire thing, but apparently this is bad etiquette, so I apologize and put the matter here for discussion. --Goodkarma 19:57, 14 October 2005 (UTC)

OK changed most of it....--Deglr6328 18:06, 15 October 2005 (UTC)

Focus Fusion (Hydrogen-Boron fusion)

Does this have even an inkling of truth or feasibility in it? Article in Open Source Energy Network.Khokkanen 12:55, 7 November 2005 (UTC)

The plasma focus is a legitimate plasma confinement configuration. It is considered to be inferior to the tokamak on the basis of experimental results, theoretical considerations, and engineering constraints. Even if there were a breakthrough in the confinement concept, proton-boron fuel has inherent problems that will prevent it from being a practical fuel. See Aneutronic fusion and Nuclear fusion#Important fusion reactions. --Art Carlson 17:12, 7 November 2005 (UTC)

"inherent problems"? Like what? No materials research funding because you aren't irradiating anything?Danielfong 14:28, 3 March 2006 (UTC)

"inherent problems" like it won't work. See Aneutronic fusion and Nuclear fusion#Important fusion reactions. --Art Carlson 17:34, 3 March 2006 (UTC)

"It won't work" obfuscates the issue, and is potentially quite wrong. It's not impossible to reach the Lawson criterion for P-B reactions, just difficult. Whether it's more economical is another matter -- it might be. I have no idea why you're being so pessimistic. Danielfong 21:41, 3 March 2006 (UTC)

Okay, I've read the wiki-articles, and the abstracts for the papers that I could dig up, and will try to get a hold of Rider's thesis. I'm not sure the basic premise is all-encompassing though. If Fokker-Planck calculations don't take into account resonances with external fields, you're neglecting a significant attractor in phase space. You wouldn't need to redistribute the particles, just restrict flow to the uglier regions of phase space. This problem does start to get difficult, however. Danielfong 08:35, 4 March 2006 (UTC)

Ugh. Evidently someone's already beat me to it. The PDF that the page references already points out this problem. The recirculating power is shown in a specific case to be less than the fusion power released -- the general calculation assumes an isotropic distribution function. The annoying part is that the part of the page that references this -misses the point entirely-. Rider's -thesis- is referenced, which can only be obtained from the MIT library. Later, a -refutation-, under PDF, is referenced, which isn't actually an article by Rider! So a fundamental limit still hasn't been found apparently... Danielfong 08:50, 4 March 2006 (UTC)

No! These devices have been around since 1964. If they could work, then everyone would be using them. From [17] we see a description of a device that uses D-D fusion, which consumes 125 joules, and yields 1e6 neutrons. That works out to be about 500 million times as much energy input as output. H-B fusion is even harder. pstudier 18:19, 7 November 2005 (UTC)

Sustainable yes, but renewable?

The reaction is one way, right? So how does it meet the definition of "renewable"? Hydrogen fuel cells combine Oxygen and Hydrogen, yielding water, and then you split them again and reuse them. When you combine Hydrogen atoms to produce Helium you are stuck with the Helium, right? So it is renewable only in the sense that we cannot imagine using so much power that we would use up the available Hydrogen, right? But who would have thought one hundred years ago that we would use as much electricity as we do now? If it is available and cheap, we will find a way to use it. Does the yield reach the point where it would make economic sense to mine the fuel from neighboring planets - even when there is plenty of Hydrogen industry could extract more cheaply here? At what point would fusion power plants start using up too much of our Hydrogen? Are we talking Ring World construction projects, or something on a more imaginable scale?

Rarebird 14:51, 28 April 2006 (UTC)

I estimate somewhere on the order of 10¹⁸ tonnes of water in Earth's oceans. That gives on the order of 10¹⁷ tonnes of hydrogen, of which on the order of 10¹³ tonnes will be deuterium. If your captured energy is about 1 MeV per nucleon (produced energy from D+D fusion is about 2.5 MeV/nucleon), you get about 10¹¹ J per mole of nucleons (not deuterium nuclei), or about 10¹⁷ J per tonne, for total extractable energy reserves of 10³⁰ J. If we imagine that we'd want to use 1 PW of power in the future (right now all of humanity uses somewhere in the 10-100 TW range), that gives us 10¹⁵ seconds of power generation, or about 30 million years before the oceans are depleted of deuterium.

Spinning up Ringworld, with a mass on the order of 10²⁷ kg, to a speed on the order of 10⁶ m/s, takes energy on the order of 10³⁹ J, so we're not in Ringworld territory. Spinning up the Moon to have a day/night cycle comparable to Earths would require moving on the order of 10²³ kg at about 140 m/s, taking on the order of 10³¹ J, so reserves are in the right ballpark for doing _some_ celestial engineering. --Christopher Thomas 18:05, 28 April 2006 (UTC)

Hmmm. Humanity, were it to have the ability to attempt engineering projects of ringworld scale, would long before have gotten the ability to harvest hydrogen from the gas giants (Saturn is apparently the easiest). So we might be able to spin up the moon one day (though I'd think putting up a system of sunshades and mirrors to achieve a similar effect would be a lot cheaper and easier). Ringworlds, by contrast, are always going to be a bit of a struggle - even carbon nanotubes are nowhere near the strength needed to make "scrith", not to mention the huge energy required to spin the Ringworld up. -See Ringworld for more details.-Robert Merkel 23:36, 1 June 2006 (UTC)

Question: Given that Renewable Energy is "from an energy resource that is replaced by a natural process at a rate that is equal to or faster than the rate at which that resource is being consumed" and Sustainable Eneregy is from "energy sources which are not expected to be depleted in a timeframe relevant to the human race": Is Nuclear fusion a Renewable Energy? Despite the fact that nuclear fusion appears to be sustainable for the next 30 million years, for it to be renewable would depend upon the rate that deuterium is renewed in the sea. As I am not a scientist I can not comment on the rate (if any) that deuterium is naturally generated in the sea - can anyone more informed do so? --Aindriú Conroy 04:43, 18 July 2006 (UTC)

Deuterium isn't naturally generated, for the most part. You can get trace amounts by irradiating ordinary hydrogen with neutrons, but virtually all of the deuterium presently around was produced in the Big Bang nucleosynthesis (when the universe was dense enough for fusion to occur but expanding quickly enough that some unburned intermediate products, like deuterium, were left over). Supplies in Earth's ocean would only increase as water was added by other sources (mostly volcanism). I'm pretty sure that the replacement lifetime of the ocean is more than 30 million years, but you'd have to ask a geophysicist to be sure. My understanding was that we aren't actually in an equilibrium yet in that regard, which would make the lifetime larger than the present age of the solar system. --Christopher Thomas 05:13, 18 July 2006 (UTC)

Let's not forget that it is a rather hypothetical energy source for human uses, particularly that it remains to be demonstrated that it is practical, economical and safe. Let's also not forget that current designs and any foreseen in the medium term will be requiring lithium for fuel, which is finite hence not sustainable and certainly not renewable. Jens Nielsen 08:51, 30 August 2006 (UTC)

Two comments:

1) Lithium is not a fuel, strictly speaking. The fusion fuels are D and T. Lithium is a consumable required to replenish the T.

2) I agree that fusion power would not be renewable but given the abundance of D and Li, good for tens of millions of years of energy production, I suggest that the definition of sustainability is met.

ClaudeSB 12:31, 30 August 2006 (UTC)

The point is that lithium is required in current designs, and lithium *is* limited: "If all the world's electricity were to be provided by fusion, known Lithium reserves would last for at least one thousand years", according to the proponents [18]. If it were to supply non-electricity energy needs too then we are down to a few centuries, and I wonder for what levels of energy consumption that applies to in their calculation. I suggest including it in the article somewhere. Jens Nielsen 13:02, 30 August 2006 (UTC)

I disagree, for two reasons. First, the statements about lithium reserves lasting for 1000 years should be taken as a lower limit (per the text), not as an upper limit. Its crustal abundance is 65 ppm, so it's not a question of absolute amount present, but of what ores are considered economical to mine. As the cost of any proposed fusion reactor's mechanisms over its maintenance lifetime are many orders of magnitude more than the cost of the lithium used over that lifetime at present market rates, a very substantial price raise could be tolerated, meaning much lower grade ores could be used (which are much more abundant than the commercial-grade ores the 1000-year estimate was likely based on, as ore abundance tends to follow a power law distribution). The theoretical upper bound, which is of course impractical to reach, is about 3 million years (2.5e+15 kg within the top 100 metres of rock for Earth's land masses, 2.5 MeV per atom of lithium-7, giving 8.6e+28 J total, with far-future power consumption at 1 PW).

Secondly, and more importantly, a D+D reactor isn't _that_ much harder to build than a D+T reactor (you need 10 times better confinement numbers, unlike the 1000x improvement needed for exotic proposals like P+B11 reactors). Both are well-understood, and D+D is actually the fuel used for most reactor tests. Given the advantages of D+D (no fussing with a lithium blanket, much more easily obtained fuel, larger fuel reserves, and more of your energy out as charged particles rather than neutrons), I'd expect it to be the version of fusion power used over the long term.

I'm not saying the world will run off of fusion power in the future (I doubt it'd ever be cost-competitive even with relatively expensive renewables like solar). I'm just saying that it _could_ run off of fusion power more or less indefinitely if humanity decided that was desirable. --Christopher Thomas 15:30, 30 August 2006 (UTC)

Wow, do people have nothing better to do than argue semantics. Really, this is ridiculous, I see a lot of scientific jargon but no science. There is no such thing as a renewable resource - S, i.e. entropy will always go up no matter what. Solar energy, a renewable resource, for example uses the sun, which is slowly burning away. So what does the term renewable resource mean in normal jargon? It means for all intents and purposes the energy source will still be there when we have all evolved beyond recognition. Again, semantics. 68.227.219.145 (talk) 04:58, 1 January 2008 (UTC)

Z-pinch

Should Z-pinch be under magnetic confinement or inertial confinement? User:DeepakKumar

Magnetic. Although there are some hybrid concepts, a simple Z-pinch is magnetic confinement pure and simple. --Art Carlson 22:21, 14 March 2006 (UTC)

Social Implications of Fusion Power

I think there should be a section on the social implications of such energy sources as fusion power. For example, the Unified Social Model proposes it may conclude the Industrial Revolution here.

This is too speculative to be included, I would argue. Danielfong 20:32, 1 May 2006 (UTC)

Daniel, I have a question for you. Just what IS a vertical displacement event? I have heard that it is a serious 'out of parameter' operating event where the tokamak vessel itself jumps off its foundation a bit and I have heard that it merely refers only to a vertical displacement of the plasma itself in the vessel during a shot where a wall bump/thermal quench may or may not occur. Do you have a source where we can read about explicitly what a vde is? I have access to PRL/science/nature/J. Plas. Phys. etc.--Deglr6328 16:27, 2 May 2006 (UTC)

Sorry I can't be more helpful -- I've only heard of these things second or third hand, probably in the way that you've heard of them. I don't remember the reference exactly, it might have actually been on one of the wikipages. Maybe someone at JET could clarify? Danielfong 20:22, 2 May 2006 (UTC)

Because it results in better confinement and because it utilizes the magnetic field better, modern tokamak plasmas are vertically elongated. One way to think of this is to add coils above and below the plasma with current in the same direction as the plasma current. Since parallel currents attract, the upper coil tugs the plasma upward, and the lower coil tugs it downward, resulting in elongation. If the plasma now moves a bit up (or down), it will be closer to the upper coil, which will thus pull even more stongly, and farther from the lower coil, whose effect will thus be weakened. The farther the plasma moves up, the stronger the upward force becomes - instability! The conducting wall or additional passive coils reduce the time constant of the instability so it is slow enough (usually!) to be actively controlled. --Art Carlson 07:31, 3 May 2006 (UTC)

Hm well that's interesting and seems to come CLOSE to answering the question but....--Deglr6328 07:54, 3 May 2006 (UTC)

VDE refers to a vertical displacement of the plasma that gets out of control, i.e. when the plasma hits the wall and quenches. As a consequence of the plasma displacement, it is true, the vessel itself may jump up as much as a few millimeters. Makes quite a thump. Honestly, I have never quite understood how momentum is conserved. And I don't have any references handy. --Art Carlson 08:12, 3 May 2006 (UTC)

cool! thank you for the info.! don't know where to add it though. maybe list of fusion experiments.--Deglr6328 17:15, 3 May 2006 (UTC)

A VDE isn't an experiment, it's an instability that needs to be controlled. You could write about the VDE active control, but that's not really the granularity that the wiki should look for.

I'm pretty puzzled as to the momentum conservation myself, but I bet it works like a skateboarder doing an olly. The tokamak pushes down, against the earth, which moves away, and then the tokamak jumps back once the plasma meets the constraint. Danielfong 02:23, 5 May 2006 (UTC)

I know its not an experiment, I just think it's a very interesting tidbit. It must have been quite a shock the first time it happened.--Deglr6328 04:37, 5 May 2006 (UTC)

How about mentioning notable speculations?

Plasma Containment

I found this article interesting, thought you might want to make some changes to the containment section of the page, I dont want to touch it since my knowledge of fusion is very limited.

Heres an extract: "Researchers at General Atomics, a company based in San Diego, California, US, discovered a simple way to prevent ELMs from occurring. By using a separate magnetic coil to induce small perturbations in the reactor's main magnetic field, they found they could bleed off enough of the plasma particles to prevent the ELMs from bursting out. The solution was tested at an experimental reactor based in San Diego called the DIII-D National Fusion Facility."

Heres the link: Nuclear fusion plasma problem tackled

It is not yet possible to judge the significance of this development, so I don't think it is appropriate to include in an encyclopedia article. At the very least we would have to first explain what ELMs are, when and why they can be a problem, what the current solution is, and so on. --Art Carlson 14:32, 23 May 2006 (UTC)

Does Size Matter?

I know that the largest fusion reactor is a star, but how small could a fusion reactor be made. For example, could it be the size of a computer monitor?

You can make small fusion reactors, but they all require you to put a lot more energy in than energy out. If present ideas about a power-generating fusion plant are implemented, they will have to be large industrial devices comparable in scope to present-day baseload generation plants. As I understand it, given the same basic confinement system design, a larger reactor will have a bigger fusion energy gain factor than a smaller one. Additionally, economies of scale will presumably apply to fusion power as they apply to fission power (and coal, and a lot of other technologies). It costs less to make one big thing than two small ones. --Robert Merkel 01:03, 30 May 2006 (UTC)

Rober Merkel's comment is accurate. I would only like to add that the problem of size is a matter of confinement. Apparantly plasmas are a lot more controllable in large spaces. If we were somehow able to invent star-trek like force fields that can compress and confine a plasma sufficiently, about any size is possible. Albester 10:39, 16 August 2006 (UTC)

Gravity

From what I understand the point where the amount of energy used to power the reactor compared to the amount of energy produced is the same is the point is when it already pays for itself. Anything more is free energy. What would the possibilities of a fusion reactor in high orbit have similar abilities to a small sun. Would the lesser amount of gravity help the reactors plasma to keep itself from hitting the walls and causing the energy to disrupt?

Gravity doesn't really have much of an effect on most fusion plasmas because the other forces are so incredibly strong. I say most because stars do exist ^^ Danielfong 05:57, 4 June 2006 (UTC)

Stars have a lot more mass than laboratory schemes. Gravity plays no role in terrestial fusion, instead, where stars use gravity as a confining power, we use magnetic fields. But you're mistaken about the small sun, every interior of a fusion chamber is a small sun in terms of heat. Albester 10:36, 16 August 2006 (UTC)

JET fusion with Q over 1.... incorrect?

"The largest current experiment, JET, has resulted in fusion power production somewhat larger than the power put into the plasma, maintained for a few seconds." This is referring to a Q greater than 1, which apparantly was never achieved by JET (http://en.wikipedia.org/wiki/Joint_European_Torus). Is there a source for JET having a higher output?

Go over to the ITER home page, there are numerous papers and articles about JET. They did achieve a Q over 1, albeit for a short time. This is no secret, but its usually put away in technical papers. Albester 10:34, 16 August 2006 (UTC)

I don't see it. where?--Deglr6328 17:00, 16 August 2006 (UTC)

How about this reference http://www.iea.org/textbase/techno/technologies/fusion/interphysics.pdf ClaudeSB 19:15, 16 August 2006 (UTC)

??? I really don't see where you are getting a figure of Q>1. All I see is a maximum Q of .64 for JET in 1997 which agrees with the JET article.--Deglr6328 04:02, 17 August 2006 (UTC)

It appears the JET article is more accurate than this one.--Deglr6328 04:36, 5 August 2006 (UTC)

The point is that, as far as I know, the higest Q in JET is less than 1 ClaudeSB 10:54, 17 August 2006 (UTC)

Oh, I thought you were trying to show the opposite! yes we are in agreement then. --Deglr6328 03:54, 18 August 2006 (UTC)

EAST China's fusion device

I read in Chemistry World that a device called The Experimental Advanced Superconducting Tokamak (East) is being built in China. I cannot find the article on the Chemistry World website, it appears to be only in the magazine. It says it 'will be the first of its kind in the world' but will be 'much smaller than ITER.' It also claims it is intended to be up and running 'by the end of the year.' I'm sure other people have picked up on this as an article exists on Wikipedia about it, but I think it should have a mention in the fusion power article. The prospect of learning more about fusion so soon certainly interests me atleast.

EDIT: Found the link, www.rsc.org/chemistryworld/Issues/2006/July/InPapers.asp

Fission-fusion power?

Just out of curiosity, does anyone here know if anyone's experimented(even just theoretically) with a staged or fusion-boosted power plant? Seems like something too obvious to have never been considered. BioTube 23:54, 21 September 2006 (UTC)

Yes it is called a hybrid reactor.--Deglr6328 05:37, 22 September 2006 (UTC)

Effluents in normal operation

The section on effluents in normal operation says that "During normal operation, some amount of tritium will be continually released. There would be no acute danger, but the cumulative effect on the world's population from a fusion economy could be a matter of concern." I disagree based on the quick calculation that a 1GW plant must destroy about 1kg of mass per year, therefore yielding ~100kg of tritium. This can't be hazardous, even if it were all vented. Maybe someone could do the calculation accurately, since I am not quite confident enough to edit the article itself.

How did you decide whether 100 kg is a lot or not? I asked the question, if 100 kg of tritium is in the atmosphere all the time, how many fatal cancers would you expect per year? (Actually, you have to consider that tritium tends to wash out into the soil, oceans, and ground water, where it is less dangerous.) I don't remember the answer I was given, but I think it was on the order of one fatality per year, at comparable with that from other power sources. I got the answer by word of mouth from an expert, which, or course, is not verifiable, so I can't really make a fuss if somebody strikes it. I don't know that such a calculation was ever published. --Art Carlson 17:55, 18 November 2006 (UTC)

Uh 100Kg is a horrifyingly large amount of ³H. The specific activity of T is ~9.8 KCi/g and the CEDE is 64 mrem/mCi. You will absolutely die if you ingest a single gram of T (dose is in the thousands of REM), I shudder to think what a 100Kg release of T in the HTO form would to to the local environment. I mean shit, the entire world inventory is only 10-20 Kg! Oh and your calculations for a 1GW plant make no sense at all. Now on to Art's question. I suspect that person was giving you an answer based on assuming an even distribution throughout the entire atmosphere since that is the most straightforward and easy question to answer. But if you really wanted to figure out the acute effects locally then this indeed becomes a very very difficult question to answer. In addition to modeling release spread patterns taking into account wind etc. you'd have to model groundwater flow and such (is it raining at the time? what is the humidity level? is there an inversion layer? how warm is it out?(defines the H oxidation rate) and so on). I would very roughly suspect an acute 100 Kg release of T₂ may result in a handfull of deaths locally but a release in HTO form (eg. from a plant fire) would be tragically serious resulting in perhaps many deaths locally if it were warm and raining, with little wind. In any case I would think such an enormous release would probably seal the fate of anyone at the plant itself. Incidentally, one person has died from T exposure. He was apparently painting watch dials, ironic no? ("Interne Kontamination mit Tritium." Minder, W. (1969) Strahlentherapie 137, 700-704.) --Deglr6328 20:39, 18 November 2006 (UTC)

Color me confused. I quite like your numbers Deglr6328, but it seems to be at odds with the widely reported numbers I quoted, that a complete T release event would result in dosage of about 1 C at 1 km (a number I found in what was otherwise a highly critical report about the economics of fusion power). I found one source, perhaps questionable, that stated the lethal dose of tritium was "under" 1 mg. Given this it seems that the numbers I posted would require perfect distribution to dilute it to 1 Cu. I'm inclined to believe your statement about the plant personel, but given that uranium is far more deadly and the typical plant has much more of it, it seems like the risk is limited. We have vacume systems on fission plants for a reason. Maury 23:51, 22 November 2006 (UTC)

Yes I can't imagine 100 Kg of T ever accumulating anywhere and even a huge fusion power plant wouldn't need such a gigantic inventory as they would presumably just burn what they breed from a Li-6 (6 or 7 ? can never remember) blanket as its made. What numbers are you working with in the 1 Ci dose scenario? Can I see the paper? As for the lethal T dose, let's calculate it. At 9.8 KCi/g of T with a CEDE of 64 mrem/mCi (or 64 REM/Ci) how much tritiated water (this would be the absolute worst (easiest to get highest doses) way to get exposed as opposed to a T gas inhalation scenario) would you have to drink to get a dose of 500 REM (~LD50 level for most people)? Well 64R from 1Ci = 500R from ~7.8Ci and that would be about 8X10^-4g or .8 mg of of T (so your 1 mg figure looks bang on if you're talking about the mass of T alone). Now if that were in HTO (singly tritiated water) form you would need to drink down: 2 x .8mg = 1.6 mg total H isotopes (.8 millimoles) burned with oxygen (.4 mmol) gives .8 mmol H20 which at ~18g/mol is ~14mg of pure HTO to give a lethal dose, about a tenth of a single drop. Which is surprisingly little I think! Someone check my math cuz I'm horrible at calculating most everything. --Deglr6328 02:31, 23 November 2006 (UTC)

Geez, it was something I looked up when I was first working on this article months ago. I do remember the gist though, they were talking about.. oh wait I found it (heh, nothing like a REALLY big monitor so you can read and google at the same time...) [19]. This doesn't have the quote I'm looking for though, I think I was reading an expanded version of this:

The AAAS estimated that each fusion reactor could release up to 2x1012 Bequerels of tritium a day during operation through routine leaks, assuming the best containment systems, much more in a year than the Three Mile Island accident released altogether. An accident would release even more. This is one reason why long-term hopes are for the deuterium-deuterium fusion process, dispensing with tritium.

Youch. Maury 02:50, 23 November 2006 (UTC)

Hm 2 Terabecquerels IS ~50 Ci so that does sound pretty serious. Hey I finally did the Asterix IV laser page so if you want to expand feel free. With the exception of the gas lasers at LANL in the 70s-80s I think we've pretty much covered all ICF lasers worldwide above a 1-2 Kj/shot level! --Deglr6328 03:08, 23 November 2006 (UTC)

Unit

The unit used to measure the amount of energy generated in a fusion reaction is the MeV (Million of electron volt). I removed the reference to a so called "Fusion Energy Unit" which is fact not used. ClaudeSB 08:05, 28 November 2006 (UTC)

Organizing and comparing different methods of fusion power

I think there should be a chart comparing the different methods of fusion power. I have done my best to organize the different methods in the following, and would appreciate any help with this incomplete, and possibly erred list:

Thanks, Kevin Baas^talk 03:02, 22 November 2006 (UTC)

List of fusion experiments--Deglr6328 03:16, 22 November 2006 (UTC)

What's wrong with what we have already, a section on confinement concepts and a list of "Methods of fusing nuclei" in the {{fusion power}} template? --Art Carlson 09:19, 22 November 2006 (UTC)

Incomplete, not informative enough, and not in a chart, like this. wiht a chart we can put things like energy levels, temperatures, sizes, cost, etc. Kevin Baas^talk 16:18, 22 November 2006 (UTC)

^ = capable of aneutronic fusion

! = uses superconductors

????

• Magnetized Target Fusion

       Yes - this should be covered, there has been research and some publications that can be referenced.
       although MTF could be considered a type of magnetic CF it is very different in many ways.
         www.nifs.ac.jp/itc/itc12/Siemon.pdf 
       MTF- Implodable liner eg at LANL
         http://fusionenergy.lanl.gov/Physics/Magnetized_Target_Fusion.htm
         http://wsx.lanl.gov/mtf.html
       MTF - Collapsable liquid vortex
         General Fusion Inc
       www.apam.columbia.edu/SMproceedings/11.ContributedPapers/11.Thio_etal.pdf 
       I'll add something to the "Other methods" section when I get time. Rod57 11:38, 31 August 2007 (UTC)
       I'm inclined to make a separate article for magnetized target fusion.  Any comments ? Rod57 12:09, 31 August 2007 (UTC)

It's been years since I looked at MTF, but my understanding was always that it differs radically from both traditional MCF and traditional ICF, so if you have enough good sources, a separate article would be appropriate. --Art Carlson 12:33, 31 August 2007 (UTC)

NON-PLASMA

• electrochemical fusion "Cold Fusion"
• ACF
  • Bubble fusion (Sonofusion)
• Piezoelectric fusion [20]

PLASMA-BASED

DPF (Dense_Plasma_Focus)

• ^Focus fusion
• ^Colliding Plasma Toroid [21][22]

ICF (HOT)

• Laser driven

MCF (HOT)

• Z-pinch
  • ^Z-machine
  • Staged Z-Pinch Fusion
• TOROIDAL
  • Reversed field pinch
  • Stellarator -twisted
  • Electric Tokamak
  • Tokamak
  • CONDENSED TOROIDAL (a.k.a. COMPACT TOROID)
    • Spherical Tokamak
    • Spheromak
    • ^Field-Reversed Configuration
    • Open Field Lines
      • !Levitated Dipole

ECF (COLD?)

• Migma
• Farnsworth–Hirsch Fusor
• ^Polywell (Bussard)

Social Impacts of Fusion

I've added a section on the social implications of fusion power. I know it seems like the article is gung-ho on this new source of power, and indeed it may provide a source of clean energy for the future. However, this discussion must also be applied to the potential problems that this source of energy could create. Advances in chemistry led to chemical weapons; in aviation, carpet bombing; in physics, to nuclear weapons. With each technological advance, mankind must take responsibility to ensure that it is only properly used; therefore, a candid discussion regarding the potential negative impacts of this technology on the face of social conflict must be included in this article. Amend as you like, or discuss with me, but please do not remove this section. —Preceding unsigned comment added by Sven43 (talk • contribs)

I did indeed revert it and for the same reasons Maury did last time. Wikipedia is not a place to publish personal essays and miscelaneous rambling thoughts. Please read Wikipedia:List of policies [23]. --Deglr6328 19:44, 31 December 2006 (UTC)