View Full Version : China to Build Tokamak Fusion Reactor

Saturday, January 21st, 2006, 09:41 PM

http://www.ptinews.com/pti%5Cptisite.nsf/0/61BAE22BFDEE5DD6652570FD0019A327?OpenDoc ument

As stated in the articles, the Fusion generator will be built using the Tokamak method, invented by Russian physicists Igor Yevgenyevich and Andrei Sakharov.

Fusion energy, as opposed to fission, is created by the fusion of two hydrogen atoms (or two protons) to form one helium atom. As you may know, the sun is a natural fusion reactor, thus this generator is also known as an "artificial sun." Although the concept behind fusion power is simple enough, the difficulty in creating the conditions necessary for fusion to occur is enormous.

Tremendous amount of heat is required to negate the natural repelling force between two positively charged protons to get them to combine, so great that fusion processes are only possible in stars. What tokamak technology does is confine hydrogen plasma (ionized hydrogen gas, ion meaning gas has a net electric charge) into a very hot and dense state through the use of very powerful toroidal magnetic field.

Saturday, January 21st, 2006, 09:45 PM
Very interesting but how do they want to manage that?

Saturday, January 21st, 2006, 11:32 PM
Very interesting but how do they want to manage that?

Good question. I thought this is something which isnt really worked out so far and scientists still work on a practicable solution.

Gorm the Old
Sunday, January 22nd, 2006, 01:16 AM
Why are they wasting their time and money ? Decades of experience with the tokamak reactor have proved only one thing : Magnetic fields cannot confine plasmas for long ehough to achieve practical fusion.

Sunday, April 30th, 2006, 07:01 AM
Why are they wasting their time and money ? Decades of experience with the tokamak reactor have proved only one thing : Magnetic fields cannot confine plasmas for long ehough to achieve practical fusion.

That's what they used to say about flying that it can't be done.. Through research plus investemnt I'm sure they'll get it..

Dr. Solar Wolff
Sunday, April 30th, 2006, 07:29 AM
A Tokamak tries to contain a hydrogen bomb within a magnetic field. Imagine how strong that magnetic field has to be? Imagine how much electricity it takes to power that magnetic field? Even if it does work, the contained fusion heat must be converted into electrical energy at a big efficiency loss.

Why not just generate plasma using fission and direct the plasma through a magnetic field to induct electricity?

Gorm the Old
Sunday, April 30th, 2006, 03:28 PM
I think that I can answer your question Dr. Wolff. I had thought of the same approach. However, more is needed than just a magnetic field. Two electrodes oriented at right angles to the magnetic field are needed onto which the ions of the plasma are directed by the magnetic field . Even tungsten would be vaporized at the temperatrure of a thermonuclear fusion plasma . However, in order for fusion to occur at all, a hydrogen plasma must be confined, even if only briefly, at an extremely high temperature (of the order of hundreds of millions to over a billion degrees Kelvin) and high density, to ensure that the nuclei encounter each other often enough. This had been achieved only instantaneously in the Tokamak. I saw it demonstrated in 1967 and there has been no significant progress since. It is because of its dismal track record, that I regard the Tokamak as a dead end.

Gorm the Old
Sunday, April 30th, 2006, 03:52 PM
Sorry, Somehow, I read "fission" in your post as "fusion" This ought to work, but, everyone forgets that uranium is an exhaustible resource also. Sooner or later we will not have sufficient fuel for fission recators. Breeder reactors create nothing. They merely convert an unusable isotope of uranium to a fissionable one. This still requires uranium, one of the rarest elements in the universe. The AEC's lapdog, Dr. Teller used to answer this objection by rearking that thorium is also fissionable, so we'll just switch to thorium. Nobody has demonstrated a workable thorium reactor. Existing reactors probably cannot use thorium, and thorium is even rarer than uranium. The refining processes are different. In short, the entire nuclear fission technology would have to be changed, at GREAT expense to use thorium.
There is a further problem with fission reactors which has been "swept under the carpet". After a long period of use, radiation damages the sdtructural materials of the reactors and the containment vessel to the point that it becomes unserviceable. By this time, the reactor and containment vessel have become so "hot" from neutron absorption that they cannot be dismantled. We are then stuck with an unsafe and useless reactor which we can't get rid of. All we can do is fill the whole structure with concrete and then post a warning to stay away from it for the next 30,000 years or so.....
If thermonuclear fusion could be made to work on this planet (It works just fine in stars, of course.) it would be much safer than fission , though not withoutbradiation hazards, both from the possible escxape of tritium and from neutron absorption by the materials of the reactor. These hazards are much less serious than those of fission reactors. Furthermore, the fuel is abundant and easily refined......However, 58 years of failure have convinced me that fusion power is not feasible.

To return, however to return to your suggestion, magnetohydrodymanic interaction with a plasma produced and heated by SOLAR energy may well be practicable. One needs a gas that will efficiently absorb solar radiation concentrated by mirrors. I suggest that iodine vapor may fill the bill.