Cold fusion
Cold fusion refers to a nuclear fusion reaction which occurs well below the temperature required for thermonuclear reactions (millions of degrees C), usually near room temperature and atmospheric pressure and often in a relatively small (table top) experiment. Due to the fact that nuclear fusion using deuterium yields large amounts of energy, uses an available fuel source, and results in small amounts of manageable waste, the ability to tap into this energy supply with cheap, and simple processes would be a revolutionary discovery.
The most famous claim of observation of a cold fusion process is palladium catalyzed fusion, which has not been widely reproduced, and is believed by most scientists not to exist. Another claim involves sonoluminescence and is often called bubble fusion. As of 2004, no scientific consensus has been reached as to the validity of this form of fusion.
Muon-catalyzed fusion is the only well-established and reproducible fusion process which occurs at low temperatures but is not able to produce net energy.
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On March 23, 1989, Stanley Pons and Martin Fleischmann at the University of Utah claimed to measure a production of heat that could only be explained by a nuclear process. Steven Jones at Brigham Young University did not observe heat but claimed to observe neutron emission that would also indicate a nuclear process. The claims were particularly astounding given the simplicity of the equipment, just a pair of electrodes connected to a battery and immersed in a jar of heavy water (deuterium). The immense beneficial implications of the Utah claims, if they were correct, and the ready availability of the required equipment, led scientists around the world to attempt to repeat the experiments within hours of the announcement.
This claim was surrounded by a lot of media hype and excitement which brought the phrase cold fusion into popular consciousness. A few months after the initial cold fusion claims, the Energy Research Advisory Board (under a charge of the US Department of Energy) formed a special panel to investigate cold fusion and the scientists in the panel found the evidence for cold fusion to be unconvincing. [1]
The most common experiments involve a metal electrode (usually palladium or titanium) which has been specially treated so that it is saturated with deuterium and placed in an electrolytic heavy water solution. The experimenters saw extra heat coming from this system which was not readily explained by the electrolytic reaction itself. Although some experiments claimed to see fusion products (tritium, helium, or neutrons) the amount of detected fusion products did not match what was necessary to explain the amount of excess heat. The initial announcement by Pons and Fleischmann in March 1989 exhibited the discrepancy between heat and fusion products in sharp terms. Namely, the level of neutrons they claimed to observe was 109 times less than that required if their stated heat output were due to fusion. In fact if the excess heat were due to fusion, the neutron flux would have been lethal.
The idea that palladium or titanium might catalyze fusion stems from the special ability of these metals to absorb large quantities of hydrogen (or deuterium), the hope being that deuterium atoms would be close enough together to induce fusion at ordinary temperatures. The special ability of palladium to absorb hydrogen was recognized in the nineteenth century. In the late nineteen-twenties, two German scientists, F. Paneth and K. Peters, reported the transformation of hydrogen into helium by spontaneous nuclear catalysis when hydrogen is absorbed by finely divided palladium at room temperature. These authors later acknowledged that the helium they measured was due to background from the air.
In 1927, Swedish scientist J. Tandberg claimed that he had fused hydrogen into helium in an electrolytic cell with palladium electrodes. On the basis of his work he applied for a Swedish patent for "a method to produce helium and useful reaction energy". After deuterium was discovered in 1932, Tandberg continued his experiments with heavy water. Due to Paneth and Peters' retraction, Tandberg's patent application was denied eventually.
In fact, even though palladium can store large amounts of deuterium, the deuterium atoms are still much too far apart for fusion to occur in normal theories. Actually, deuterium atoms are closer together in D2 gas molecules, which do not exhibit fusion. The closest deuterium-deuterium distance between deuterons in palladium is approximately 0.17 nanometers. This distance is large compared to the bond distance in D2 gas molecules of 0.074 nanometers.
There are still a number of people researching the possibilities of generating power with cold fusion. Dr. Michael McKubre, director of the Energy Research Center at Stanford Research International, has continued to pursue cold fusion research and thinks a working cold fusion reactor is possible. Dr. Edmund Storms, a former scientist with The Los Alamos National Laboratory in New Mexico, maintains an international database of research into cold fusion.
Robert L. Park (2000) gives a thorough account of cold fusion and its history which represents the perspective of the mainstream scientific community.
Two other sceptical books from the scientific mainstream are those by Frank Close (1992) and John Huizenga (1992). Huizenga was co-chair of the DOE panel set up to investigate the Pons/Fleischmann claims, and his book is perhaps the definitive account of the cold fusion affair.
Eugene Mallove's Fire from Ice (1991) is the best-written account from the pro-cold-fusion perspective.
In March, 2004 the United States Department of Energy decided to review all previous research of cold fusion in order to see whether further research was warranted by any new results.
Information
Palladium Catalyzed Fusion
Continuing efforts
See also
References
External links
News