josh@klaatu.rutgers.edu (J Storrs Hall) (03/25/89)
Grabbed from sci.space at the suggestion of the author: From: dietz@cs.rochester.edu (Paul Dietz) Subject: Re: Room Temperature Fusion - possible indication? (In the following, preface all references to the discovery with modifiers like "reported", "claimed", etc. and statements by "assuming it is not a hoax...".) I believe the discovery might be what is known as "pycnonuclear fusion", meaning fusion induced by high densities rather than high temperatures. Even in thermonuclear fusion, the fuel nuclei do not have enough energy to actually touch, in a classical sense. Rather, they can come close enough so that they can tunnel together in the very short time before they scatter. In pycnonuclear fusion, the atoms are compressed statically. They therefore have a much longer time in which to tunnel. However, because the tunneling rate goes down exponentially with distance, they still must be quite close. The nuclei need not be moving -- pycnonuclear fusion can proceed even at absolute zero. I wonder if the reaction proceeds by one deuteron tunneling into the other, forming a compound nucleus that splits, or by the tunneling of a single nucleon from one nucleus to the other. One of the researchers said on Macneil-Lehrer that the densities achieved are the same as gaseous D2 compressed to 10^27 atmospheres (!). I would like to know how this was computed. Nowhere on the news was it reported how fast the reaction actually goes, although it was implied that the energy released exceeded the energy supplied. It might be possible to use slightly enriched water to suppress D+D reactions in favor of H+D-->He3+gamma reactions. This would be largely aneutronic. I imagine there might be problems in operating a reactor at high temperatures -- the water would boil, and deuterium would diffuse rapidly out of the electrode. Perhaps one could use high pressure to raise the boiling point, or inject deuterons with a low energy ion beam. Also, one could achieve high thermodynamic efficiencies by stopping the neutrons and gamma rays in a separate, insulated high temperature collector. Nuclear proliferation may have just become a lot easier. I am moderately surprised that it wasn't classified. Maybe it will be now? :-) Paul F. Dietz dietz@cs.rochester.edu
csimmons@oracle.COM (Charles Simmons) (03/26/89)
In recent articles appearing on the net, two concerns appear to be widespread: 1) There is a strong fear that the claimed fusion discovery is either a hoax, or the result of faulty research. 2) It has been pointed out that Platinum and possibly Paladium are rare and expensive elements that are controlled by countrys which are either historic enemies of the "west" or immoral entities. Since I tend to be something of an optimist, I would like to respond to these negative fears. As a layman, I had previously heard of two avenues of research in the search for fusion reactions. One avenue attempts to create fusion reaction by subjecting hydrogen isotopes to extremes of heat and/or pressure in order to force the isotopes close together. The second approach is muon catalyzed fusion reaction, which "shrinks" hydrogen isotopes so that it is easier to push the nuclei of the ions close together. The current claimed discovery of fusion reactions at room tempature were produced via a third avenue of research. In this "new" avenue of research, chemical methods are used to move hydrogen isotopes close together. From: dietz@cs.rochester.edu (Paul Dietz) I believe the discovery might be what is known as "pycnonuclear fusion", meaning fusion induced by high densities rather than high temperatures. For me, the important result of the recent claims is not the accuracy of the claims, but rather the attention that is being focused on a new line of research. The idea that a chemical mechanism could be used to bring hydrogen isotopes together seems quite reasonable to me, now that I've heard of the idea. (And, I am, of course, a complete layman when it comes to physics or chemistry.) I would be interested in hearing from Paul Dietz or other knowledgeable people comments on the extent to which "pycnonuclear fusion" has been researched in the past. (We note that a nanotechnological fusion reactor would make use of "pycnonuclear fusion". A "conveyor belt" would carry hydrogen atoms to a nanomachine that basically consisted of two "arms". Each arm would pick up a hydrogen atom off the conveyer belt. The two arms would then press the hydrogen atoms very close together so that the hydrogen would fuse. :-) The second point to be raised would be that at this early stage of research, the fact that Platinum and Paladium are expensive is relatively immaterial. If, as I hope, pycnonuclear fusion research is in its infancy, then researchers stand a good chance of discovering numerous other materials that can be used to produce fusion reactions. In summary, if pycnonuclear fusion reactions have not been extensively researched, then the recent announcement is something to get very excited about, even if the recent claim of fusion is shown to be incorrect. It appears that the number of primary avenues of attack on the fusion problem has just increased from two to three. Certainly many years of research will be needed to find an economical configuration of materials for producing the fusion reaction, to show that a sustainable reaction which produces more energy than it consumes is possible, and to produce a prototype fusion reactor. -- Chuck [The nanotech arms would very likely be blown apart by the (single) fusion and would have to be rebuilt for each pair of deuterons. This may be more trouble than it's worth. Fusion may remain a bulk process, and the role of nanotech may be to produce appropriate crystal structures for it to take place in. On the other hand, *if* it becomes possible to control (or even predict) which direction the products will emerge in, nanotech wins big, and kilowatt powerpacks the size of a jellybean become a real possibility. --JoSH]