Talk:Fusion power

From Academic Kids

Template:Energy development Has anyone else heard of focus fusion which uses hydrogen-boron fusion. www.focusfusion.org

Surely the cost of development plays little role in the long term economics of fusion power. Fusion will be developed sooner or later, be it in 20 or 200 years, simply out of human curiosity and for prestige reasons. After that, its economic viability, and its long term success is a question of operating costs only. 137.222.40.132 23:21, 28 Jan 2005 (UTC)

Contents

1 Request for Statistics from Anonymous user 2 Will ITER displace other research into fission? 3 Do Generation and Extraction of Energy (by and from fission reactions) Differ? 4 Risks of fission belong in the fission article 5 Do fission and fusion use up their reactants? What is 'reduction of radioactivity?' 6 Cross-Over Point? 7 Moving heating here 8 Plasma heating 8.1 Ohmic heating 8.2 Neutral-beam injection 8.3 Magnetic compression 8.4 Radio-frequency heating 9 Chain reaction 10 Censorship of Critical Fusion History in Wikipedia 11 Overhaul

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 (http://en.wikipedia.org/w/wiki.phtml?title=Talk:Nelson_Mandela&diff=2498390&oldid=2480054), 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)

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 (http://www.jwz.org/doc/worse-is-better.html)).
3. that's what the people working on the inertial designs think about ITER.

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. (http://www.straightdope.com) - 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)

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)

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.

Plasma heating

In an operating fusion reactor, part of the energy generated will serve to maintain the plasma temperature as fresh deuterium and tritium are introduced. However, in the startup of a reactor, either initially or after a temporary shutdown, the plasma will have to be heated to 100 million degrees Celsius.

In current tokamak (and other) magnetic fusion experiments, insufficient fusion energy is produced to maintain the plasma temperature. Consequently, the devices operate in short pulses and the plasma must be heated afresh in every pulse.

Ohmic heating

Since the plasma is an electrical conductor, it is possible to heat the plasma by passing a current through it; in fact, the current that generates the poloidal field also heats the plasma. This is called ohmic (or resistive) heating; it is the same kind of heating that occurs in an electric light bulb or in an electric heater. The heat generated depends on the resistance of the plasma and the current. But as the temperature of heated plasma rises, the resistance decreases and the ohmic heating becomes less effective. It appears that the maximum plasma temperature attainable by ohmic heating in a tokamak is 20-30 million degrees Celsius. To obtain still higher temperatures, additional heating methods must be used.

Neutral-beam injection

Neutral-beam injection involves the introduction of high-energy (neutral) atoms into the ohmically-heated, magnetically-confined plasma. The atoms are immediately ionized and are trapped by the magnetic field. The high-energy ions then transfer part of their energy to the plasma particles in repeated collisions, thus increasing the plasma temperature.

Magnetic compression

A gas can be heated by sudden compression. In the same way, the temperature of a plasma is increased if it is compressed rapidly by increasing the confining magnetic field. In a tokamak system this compression is achieved simply by moving the plasma into a region of higher magnetic field (i.e., radially inward). Since plasma compression brings the ions closer together, the process has the additional benefit of facilitating attainment of the required density for a fusion reactor.

Radio-frequency heating

High-frequency electromagnetic waves are generated by oscillators (specifically, often by gyrotrons or klystrons) outside the torus. If the waves have a particular frequency (or wavelength), their energy can be transferred to the charged particles in the plasma, which in turn collide with other plasma particles, thus increasing the temperature of the bulk plasma. This technique is also called electron cyclotron resonance heating or ECRH.

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 (http://www.geocities.com/jim_bowery/BussardsLetter.html) 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 [1] (http://www.geocities.com/jim_bowery/miufo.html), you harbor bizzare pseudoscientific ideas about genetics and biology [2] (http://www.geocities.com/jim_bowery/god.html), your essay on why you think "Immigration Causes Autism" appears to be thinly veiled racism [3] (http://www.geocities.com/jim_bowery/imbamcoa.html) (and weather you are aware of it or not racists endorse your views [4] (http://64.233.161.104/search?q=cache:Z8m0f_5EgNAJ:www.revilo-oliver.com/Kevin-Strom-personal/links.html+stormfront+%22jim+bowery%22&hl=en)), you seem to think the cydonia Mars face is of artificial origin [5] (http://www.geocities.com/jim_bowery/cydoniaface.html), you are rabidly anti-semetic [6] (http://groups-beta.google.com/group/alt.conspiracy/msg/9ec5472fd2b132ee?q=author:Jim+author:Bowery&start=120&hl=en&lr=&ie=UTF-8&scoring=d&as_drrb=b&as_mind=12&as_minm=5&as_miny=1993&as_maxd=1&as_maxm=6&as_maxy=1996&rnum=121) as others have noted [7] (http://www.kuro5hin.org/story/2003/6/1/224357/0707). In conclusion, as many others have already noted [8] (http://groups-beta.google.com/group/alt.politics.nationalism.white/msg/9d280205c8f27ae?q=jim+bowery&hl=en&lr=&ie=UTF-8&rnum=5) 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 [9] (http://en.wikipedia.org/w/index.php?title=WASP&diff=prev&oldid=5382799), [10] (http://en.wikipedia.org/w/index.php?title=Manifest_Destiny&diff=prev&oldid=3058224). 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[11] (http://en.wikipedia.org/w/index.php?title=Special:Contributions&target=131.191.88.246) Mr. 131.191.88.246?? I wonder who you could be!? Jim Bowery is that you!?! Goodness you're [12] (http://en.wikipedia.org/w/index.php?title=Special:Contributions&target=164.116.47.178) 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 (http://slashdot.org/comments.pl?sid=135341&threshold=3&commentsort=0&tid=149&tid=95&mode=nested&cid=11293634). — Ævar Arnfjörð Bjarmason (http://academickids.com/encyclopedia/index.php?title=User_talk:%C6var_Arnfj%F6r%F0_Bjarmason&action=edit&section=new) 05:41, 2005 Jan 8 (UTC)

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.

• 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

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 [13] (http://www.lle.rochester.edu/)) 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)