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Sorry, that should be: very seriously

The Europeans are taking fusion very seriously and making nice progress.

You are aware of things like JET? While it is still experimental for more practical usage, it still has been able to successfully preform fusion reactions. Also, the hydrogen bomb is powered by nuclear fusion.

Just a few corrections. "Huge tokamak reactors" have been built before and are currently operated (see for example Joint European Torus).
Secondly, you say that as if both confinement techniques require tokamaks. This is not so. Inertial confinement makes use of lasers for the confinement, and requires no tokamak. I am not saying this is better, just that it has very different requirements.

Does that cost represent the first power-generating plant or the expected cost if a lot are built? If the latter, I'd be surprised. The most recent assessment I know of is the European Power Plant Conceptual Study, which suggests costs in the range of 1-2 times current generation (e.g. coal or fission) depending on level of maturity. Not compelling, but not hopeless either.

One of the ways they have improved things is to use supercooled magnets as part (I think!) of the plasma containment system as (as we all know!) supercooling the magnets makes them superconductors and therefore MUCH cheaper to run (even factoring in the cost of supercooling the suckers). The LHC uses a similar method.

The excellent BBC Horizon program on "How to build a star on Earth" with Prof. Brian Cox talked about all this stuff in a quite approachable way, although I'm sure accusations of bias could be levelled at their enthusiasm for the subject, it was encouraging when he asked all the scientist how likely and how long and they all had a high percentage for "How likely" (80%+) and how long (15 to 25 years).

He ended with the thought that this tech could come MUCH sooner if we decided it was a good bet and invested in it, which could be the words of a snake-oil salesman or it could be the answer to the Earth's energy needs. Certainly just wheeling out the cliched "It's always been 20 years away" mantra doesn't really help. I'd say we should throw the money at it now - it certainly won't be as big a waste of funds as some of the other things we seem so happy to spend money on, and could be the first genuinely big step humanity's made for a long while!

One of the ways they have improved things is to use supercooled magnets as part (I think!) of the plasma containment system as (as we all know!) supercooling the magnets makes them superconductors and therefore MUCH cheaper to run (even factoring in the cost of supercooling the suckers). The LHC uses a similar method.

The excellent BBC Horizon program on "How to build a star on Earth" with Prof. Brian Cox talked about all this stuff in a quite approachable way, although I'm sure accusations of bias could be levelled at their enthusiasm for the subject, it was encouraging when he asked all the scientist how likely and how long and they all had a high percentage for "How likely" (80%+) and how long (15 to 25 years).

He ended with the thought that this tech could come MUCH sooner if we decided it was a good bet and invested in it, which could be the words of a snake-oil salesman or it could be the answer to the Earth's energy needs. Certainly just wheeling out the cliched "It's always been 20 years away" mantra doesn't really help. I'd say we should throw the money at it now - it certainly won't be as big a waste of funds as some of the other things we seem so happy to spend money on, and could be the first genuinely big step humanity's made for a long while!

What we need is some CERN-scale collaboration on this so that we can possibly help to alleviate the energy strains on the global populace.

You means something like JET http://www.jet.efda.org/ or ITER http://www.iter.org/ ?

Meanwhile, the guys over at EFDA have almost got there too... http://www.efda.org/fusion_energy/fusion_research_today.htm

The catch to these devises appears to be that if you have a strong enough electrostatic field to contain the ions then you will also lose A LOT of high energy electrons (Rider 1995), thus reducing the confinement efficiency. As Rider notes, capturing the escaping electrons to recover their energy may make the scheme feasible for D-T fusion ( there are other issues as well however).

Personally I think stellarators are more promising. For those who don't know stellarators are a bit like Tokamaks, except rather than relying on an electric current in the plasma to create the necessary twist to the magnetic field for confinement, they twist the confinement vessel itself ( a bit like a moebius strip ), making them a lot more stable than Tokamaks, and allowing them to operate continuously (You can't induce a DC current in the plasma so Tokamaks necessarily operate in pulses ). Main problem seems to be that since stellerators have a lot less symmetry than Tokamaks the calculations become more difficult, but if computing power continues to rise this will probably be solveable.

As a bonus stellarators look damn cool ; )
http://www.efda.org/pictures_html/stellarator_schema_and_live.jpg
http://www.psl.wisc.edu/hsx.jpg

JET was the highly successful predecessor to ITER.

http://www.jet.efda.org/pages/faqs/faq4.html

Q: Even if you could sustain fusion for prolonged periods, how do you extract power from the reactor?
A: A nuclear fusion power plant would be no different from a "conventional" power plant in the sense that the path of energy to the grid would be via a heat exchanger to a steam generator to turbines. The heat would be extracted from the lithium "blanket" inside the reactor wall which would absorb the neutrons created by the deuterium/tritium fuel.

Q: What is a "lithium blanket" and how does it work?What happens to the neutrons after they're "absorbed" by the lithium blanket?
A: The Lithium blanket is a layer of Lithium that will surround the burning plasma in a potential fusion powerplant. It will absorb the energy from the fusion neutrons produced in the plasma, boiling water via a heat exchanger, which will be used to drive a steam turbine and produce electricity. The Lithium will also react with the neutron to produce Tritium (a heavy form of Hydrogen) which will be used as a fuel for the plasma, along with Deuterium (another heavy form of Hydrogen).

HTH

http://www.jet.efda.org/pages/history-of-jet.html talked about "a 65% ratio of fusion power produced to total input power."

Did they really break even, i.e. 100%?

Why is everyone so skeptical? There are already working nuclear fusion reactors. Only minor improvements are needed to go beyond break-even.

http://www.jet.efda.org/

JET http://www.jet.efda.org/ has been doing fusion for quite a while.

"Splitting those atoms is the only sure way we have to keep our economy alive and to do so without destroying our climate."

So what happens when we hit peak uranium? There are two major uranium isotopes, only one of which is suitable for use as nuclear fuel. It's also the one that there is the least supply of. The two isotopes together can be used to create vast amounts of plutonium, but nobody considers that a viable alternative because it could mean the proliferation of nuclear weapons. The only REAL alternative is not splitting atoms, but fusing them. That technology is being developed, but it won't be ready till mid-century. When it gets here, the use of deuterium and tritium as fusion fuels will provide us with enough energy for several million years (though our lithium supplies will run out much earlier, still well beyond even our great-grandchildren's lifetimes), but we need something to sustain us till then. Fission may help as a stopgap measure, but it's no replacement for oil.

And of course all of this ignores oil as used in the production of goods, such as plastics. Processes such as thermal depolymerization may assist in this, but that's still largely unproven technology.

It's gonna be a rough couple of decades, children. Better buckle up.

Please people, this is not for cold fusion use - its for starting a hot fusion process. That needs millions of degrees celcius, high material density and so forth. This is one promising solution for the hot fusion "spark plug". http://www.jet.efda.org/
The key to hot fusion is material density and temperature, containing the plasma is extremely hard.

IANANP (I am not a nuclear physicist) but a lot of people don't seem to know much about fusion so here are some links which explain a bit more about it:

http://www.jet.efda.org/pages/content/fusion2.html
http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/ fusion.html
http://en.wikipedia.org/wiki/Timeline_of_nuclear_f usion
http://www.fusion.org.uk/
http://www.iter.org/

Electrical Storage:
Hydrogen conversion is at presenly only 65% efficent versus 85% for a hydro storage system

http://www.electricitystorage.org/tech/technologie s_technologies_pumpedhydro.htm

and

http://www.electricitystorage.org/tech/technologie s_technologies_flywheels.htm

http://www.esru.strath.ac.uk/EandE/Web_sites/03-04 /marine/tech_storage.htm

http://www.jet.efda.org/pages/focus/004power/

http://www.esru.strath.ac.uk/EandE/Web_sites/03-04 /wind/content/storage%20available.html

http://www.geocities.com/dfradella/homepage.htm

When I visited JET back in 2001 they said they were achieving sustained reactions over several tens of seconds (~30) before the plasma became unstable.

Fission reactors are easier to manage but still 30 minutes of reaction is pretty substantial.

Well, my old powerstation used to manage several months of continuous fission reactions on each reactor, before thunderstorms or welding operations or rod-drops would cause the reactors to come off. In theory, a reactor could be run continuously for 2 years i.e. between statutory (legal) biennial outages. These were reactors designed in the late 1950s.

Reactor design is not simple, there are many things to think about, how to moderate, how to cool down, how not to overheat (this is critical because the claddings around the elements usually get weaker when heated and crack. Once cracked, you cannot stop contaminating the water used for the reactor).

Here in the UK most of our reactors are gas-cooled (using carbon dioxide). We have one commercial PWR in Suffolk (Sizewell B). The Magnoxes were positive-feedback systems and could, in theory, overheat, but in practice the passive safety systems prevented this. The AGRs avoid this problem (caused by plutonium resonance with the thermal neutrons and graphite moderator) by holding the graphite temperature steady, by providing the graphite with it's own cooling loop (actually the first stage of core cooling, the gas then gets passed over the fuel). In effect the cold gas coming in cools the moderator, picking up some heat (being pre-heated) and then cooling the fuel, up to about 650 degrees C IIRC.

This all relies on active feedback systems as it is a chaotic system (in conjunction with the boilers).

If an AGR looses forced cooling, it's quite dangerous, as there is a maximum period of time in which you must get the automatic system back up and running. Otherwise you risk ruining your boilers. The "superheat" part of the boilers must under no circumstances get wet or else they are knackered forever, and your powerstation is useless. (AGRs and the two concrete pressure vessel Magnoxes, Oldbury and Wylfa, have "once-through boilers" which are a unique British design developed specifically for nuclear reactors and used nowhere else in the world).

AGRs are better than PWRs in another respect and that is the reactor pressure vessel is too strong to ever develop a significant breach that would result in a depressurisation and catastrophic release of radioactive substances.

Unfortunately, Margaret Thatcher chose a PWR for Sizewell B to improve Anglo-American relations. PWRs do not have concrete pressure vessels and are more "dosey" that AGRs (and the two concrete Magnoxes). They od have a sealed containment building, whic saved the day at Three Mile Island, but this is not required in an AGR or PBMR since the pressure vessel is much stronger and the failure modes are different. AGRs can not melt their fuel even with no forced convection, as long as you keep water in the boilers.

Try, I don't know, reading the fine article in the story.

Fact is, there are plenty of working fusion reactors.

You could even build one yourself.

We know of one working fusion reaction - the sun. We know of many designs and fuel types we can use for controlling fusion reactions here on Earth, such as Tokamok and Tritium & Dueterium, respectively.

What we don't know is how to construct a reactor that will actually give us a net positive energy gain(i.e. Put out more energy than we put in) so as to effectively replace all those nasty other methods of generating electricity, like coal or fission.

This is why we are still researching new ways of acheiving fusion that could lead to new perspectives or breakthroughs in the field, like the experiment in the, ahem, fine article.

The largest fusion reactor in the world (Joint European Torus, JET) is located in Culham UK and is funded by EFDA so I think it's a little unfair to say that the EU doesn't have sufficient funding for fusion research.

Well, Europe also has already got one. What they are talking about now ist the next generation...

The plasma does not constantly bump into the walls of the container. As some previous posters have touched on, if the plasma touches the walls of the vessel it loses so much of its power that the reaction dies.

Another problem is that if the current in the plasma passes through the walls of the vessel it creates a magnetic field around them which kicks against the plasma's own magnetic field with incredible force. This is called a disruption, and it kills the plasma. Back in the project's infancy a particularly bad disruption actually caused the entire torus to jump a clear centimetre off the floor. If that doesn't sound impressive then you need to have another look at a picture of the torus!

I had the privlidge of working at JET during the third year of my degree*, and I can say that JET has some of the coolest gear and cleverest people working there that I have ever seen.

For anyone who's wondering about the computing equipment they use: they have a lot of big Sun servers which host X sessions from Linux PCs or some Xterminal like things called Igels (they also still use some original X Terminals.. I don't know if those are still in production?) on which most development is done. They use Linux in as many places as they can, including a ~80 node analysis cluster (JET produces data at a rate of about a gigabyte a day during operations). Windows PCs are available for desktop use by those who prefer them.

* If anyone thinks my very basic description of the physics is a sign of BS, I should point out that I was there as a Software Engineering student, not a physicist.

If anyone is interested there is a wealth of information on JETs website

Including some pretty cool pictures of their kit.

If anyone is interested there is a wealth of information on JETs website

Including some pretty cool pictures of their kit.

Actually the residual radioactive materials last 50-100 years so we'll still have a waste problem with decommissioned plants.

I recently saw the 'fusion roadshow' by our national plasma research institute. Although it was actually targetted at highschools it was great fun to watch with a whole audience of physicists. Their predictions were however a little bit negative: almost all of the fossil fuels will be used up in the next century when we achieve a maximum population of around 10 billion. Renewable energy sources such as wind power and hydraulics will be used more, but they will never be able to supply more than 25% of total demand. Their obvious answer was to invest in nuclear fusion now, all the other types cannot be scaled up enough.

Apparently the current best fusion reactor, JET, is close to break even point (energy in versus energy out). The future project ITER, to be built in France/Japan/Spain (depending on politics), will be the first to actually be a net energy producer. This will still only be a research plant. Production type plants are expected around 100 years from now, mightbe just in time to save us when the oil dries up.

The next one in the pipe is ITER.
Don't forget Canada and Spain as potential homes.

[1]Yes, I know about changes to H2 specific heat with temperature - orders of magnitude is all the precision we need here.

It's always amazing how the people in charge (or that sponsor the project) seem to 'forget' this little detail. But, in fact, the critics are right. Billions and billions are wasted, on something that they know full well will never amount to a working fusion reactor that actually delivers energy to the market. The design (and goals, btw) are extremely unsuited to accomplish that, especially compared to the JET-project - http://www.jet.efda.org/ - (or actually the ITER-project).

And all the 'new things that have been learned' does not weigh up against the billions spend on it. The REAL reason (which they never mention) that they have gone through with this, is because of military pressure and animousity between the EU and USA on some key issues. Because, while a tokamak design yields the best results and opportunities for actual energy-output in a sustained, marketable way, the laser-pellet system is a lot more usefull in one respect: the study and experimentation of atomic/hydrogen fussions as they occur in bombs (explosive output). THAT is why they went for that project, because for usefull civilian experimentation, other ways of attaining nuclear fusion are far better suited.

Strange how you never seem to hear that aspect from the scientists/politicians involved.

• in 1997 JET produced 16MW which was 65% of input (210 seconds sustained)
• Actual Confinement time vs Predicted Confinement time graphs show damn close to 1:1
• The next major project ITER has a goal of producing 500MW(thermal)
• ITER is still purely a research project, still discussing sites, first plasma expected 2020, Q factor (power out/power in) of ~10
• After that DEMO (ie Demo Power Station) will aim for 2GW thermal and net electricity production
• Thirdly PROTO (Prototype Power Station) aims to generate 1.5GW of electricity

Last time I checked, Canada, Russia and China preferred the Japanese site.

• EU (28%)
• Japan (28%)
• Russia (14%)
• USA (10%)
• China (10%)
• South-Korea (10%)

Controlled fusion has been "just around the corner" for some time. If I were "in charge", I'd set up a Manhattan Project-like effort to get controlled going - it's that important. Of course, the Bush family and its web of fine compatriots would do whatever they could to stop it. Sigh.

I am in high school and very interested in physics and it would be an awsome project to work on something like this.

Where have I heard this type of thing before?

You may think this is the ultimate chick "magnet," but personally, I think that even if fusion reactors only get a second place in the science fair these days, you should try to build a Tokomak. There's just something sexy about how they look.

After the fair, no matter how you do, you can take a promising date to see it, dim the lights and crank it up and see if sub-nuclear particles are all that get excited. Who knows, maybe you'll finally discover the joys of practical applications for combinatorial physics, where books have only given you theories to feed your fantasies...

(moderators: please don't "nuke" me too badly on this one)

I am in high school and very interested in physics and it would be an awsome project to work on something like this.

Where have I heard this type of thing before?

You may think this is the ultimate chick "magnet," but personally, I think that even if fusion reactors only get a second place in the science fair these days, you should try to build a Tokomak. There's just something sexy about how they look.

After the fair, no matter how you do, you can take a promising date to see it, dim the lights and crank it up and see if sub-nuclear particles are all that get excited. Who knows, maybe you'll finally discover the joys of practical applications for combinatorial physics, where books have only given you theories to feed your fantasies...

(moderators: please don't "nuke" me too badly on this one)

I think JET uses/used this technique to get a load of current to the bits which heat up the plasma. I could be wrong though.

As Ken Finkelman once said, 'CANDU can't do'. Nuclear power in unsafe in communist hands and CANDU is a good pun, certainly - but I wouldn't call the Japanese communist, nor would I call the CANDU reactor safe, in either Korean hands or Canadian hands, though that may be due to all the pinkos up here. Regardless, fusion power will probably be the long-term solution to energy demands. It solves the principal problem of fission - radioactive waste - while introducing no new problems of its own, aside from the inevitable problem of finding out how to build something never built before.

Fo mo info, go to http://www.jet.efda.org

Here is a link to a European fusion project: JET

Obasan

If a tree falls in the forest, and kills a mime, does anyone care?