Fusion power plant!!!

Didn't hear anything about it any links?

The BBC News site as 3 different articles about it. I read them earlier today.

1. Powerful Dream
2. France Gets Nuclear Fusion Plant
3. Q&A Fusion

I think they'll have something built by the end of this year. But they expect the designing of a commercial prototype fusion power plant to take at least a decade. I believe the biggest problem is creating materials for the doghnut shaped reactor that can survive the heat needed for nuclear fusion - which is a few times the heat at the centre of the sun!

The Japanesse are supposed to have researched heavily in this materials area already. Maybe everyone feels they would be have a technological monopoly if they pulled off fusion in their own country. There's a lot of political and commercial issues involved, as can be seen by manner in which Japan stepped out of the race for the reactor - to get a percentage of research papers produced by the other nations.

I don't fully get it myself. But if the consortium pulls it off, they'd see themselves in a a very favourable position for future trade.

It's very big news alright, and deserving of more media attention given the way oil prices are going at the moment.
Materials are a major engineering issue. Energy has to be transported away from the reaction area in order to (a) stop parts of the reactor vessel being heat damaged (b) allow the energy to be used to generate electricity as with a conventional power plant (although this will not be done in this plant). The materials also have to be able to withstand being irradiated by the high energy neutrons which are produced by the fusion reaction. Finally, a working fusion reactor will produce some of its own fuel (tritium) by a 'breeding' reaction. The vessel will be clad in a lithium 'blanket'. When neutrons from the fusion reaction collide with the lithium blanket they will produce more tritium by a fission reaction. This complicates things even more as lithium is very chemically reactive and therefore is a difficult substance to work with.

cregser wrote:

I believe the biggest problem is creating materials for the doghnut shaped reactor that can survive the heat needed for nuclear fusion - which is a few times the heat at the centre of the sun!

Couple of questions, may be stupid ones cause I'm not a physisist (can't even spell it!) but anyway ...........

1) Why do they need a temperature a few times that at the center of the sun? Isn't the sun a big fusion reactor so why can't they use the actual (or near) temperature of the sun cause it works there? Probably something to do with the size of the sun but hey.

2) How do they generate and sustain a temperature that high without melting the ....... well ....... the Earth?

3) What kind of output will it generate?

Nuclear fusion will be really cool if they get it to work, the oil companies will go loco!

Panserborn wrote:

Couple of questions, may be stupid ones cause I'm not a physisist (can't even spell it!) but anyway ...........

1) Why do they need a temperature a few times that at the center of the sun? Isn't the sun a big fusion reactor so why can't they use the actual (or near) temperature of the sun cause it works there? Probably something to do with the size of the sun but hey.

2) How do they generate and sustain a temperature that high without melting the ....... well ....... the Earth?

3) What kind of output will it generate?

Nuclear fusion will be really cool if they get it to work, the oil companies will go loco!

This link explains it.
http://www.jet.efda.org/pages/content/fusion1.html

Off topic:

While we are on the general topic of fusion, could someone explain to me how people think could fusion could work? It seems a bit implausable to me, the notion that there is some magic catalyst that will initiate fusion at room temperature or whatever.

Just curious, being a layman.

Shabadu wrote:

It seems a bit implausable to me, the notion that there is some magic catalyst that will initiate fusion at room temperature or whatever.

From what the discovery channel told me, the two that claimed to achieve cold fusion done it at something like 50,000C or something. Don't pull me on the actual number, it was a long time ago that I saw it. Anyway, the point is that they never done it at room temperature, just a temperature way cooler then the temperature of "regular" fusion.

Shabadu wrote:

Just curious, being a layman.

I'm a biologist but physics is cool as long as us Laymen stay away from equations! :rolleyes:

roffle @ Cap't Midnight.

Do you honestly think I was implying that the fusion reactor in France had anything to do with cold fusion? I said i was going off topic. I was curious about the concept of cold fusion, I said it didn't seem plausible to me.

panserborn wrote:

From what the discovery channel told me, the two that claimed to achieve cold fusion done it at something like 50,000C or something. Don't pull me on the actual number, it was a long time ago that I saw it. Anyway, the point is that they never done it at room temperature, just a temperature way cooler then the temperature of "regular" fusion.

Thanks, this makes more sense

Those guys still maintained they achieved it, despite no other lab showing the same results, don't they? It's curious.

Shabadu wrote:

Those guys still maintained they achieved it, despite no other lab showing the same results, don't they? It's curious.

So they say. Its never been proven and I vaguely remember that there was controversy on if they were bold face lying about the experiment. It may have happened though - we live in hope!

I am open to correction here as I am not a physicist and this is from memory. There are three components from what I recall.

Temperature - far in excess of the heat of the sun in order to force the reaction under way. It causes the gas used to become superheated plasma. They use accelerators to do this.

Pressure - required to force or fuse the ions together.

Magnetism- This is the key part - it used to keep the plasma under control and away from the walls of the reactor.

If the plasma is not kept under control it rapidly loses heat and pressure. At this stage the reaction is not self-sustaining - this is the Holy Grail.

Once they get all three in harmony by getting the reaction to sustain itself for long enough(a few seconds AFAIK) huge energy is generated and this can be translated into electrical power using heat transfer as in current fission reactors.

The simplest proposal and one regularly touted as the most likely are the isotopes of hydrogen; deuterium and tritium which when fused become alpha particles (helium without electrons). And seawater is the potential fuel as it contains ample quantities of both. Hence the "unlimited energy" angle.


The ITER is a takomak reactor - a torus (doughnut shaped) and is the next generation experiment. The last big project was the JET based in Cambridge from the early 80s.

It is one of the few areas of science where all the big spenders (Japan, EU, USA) have worked together. It was agreed on JET that the research costs are far too expensive to be carried by any one country and that co-operation was the way forward. Up to that point they were all running expensive research of their own. Takomaks are of Japanese design.

It is not anticipated that we will get a working fusion reactor until the second half of the century.


As regards cold fusion it has never been proven to work.