A 鈥渃old fusion鈥� experiment in California has produced tantalising results 鈥� but critics say they may not indicate that any kind of nuclear reaction has actually taken place.
Most physicists treat claims of cold fusion with derision. However, an underground of enthusiasts has continued performing experiments which, they say, demonstrate that deuterium nuclei can fuse to produce tritium and helium isotopes during the electrolysis of heavy water with palladium electrodes. The few outsiders who have tried to repeat the experiments have failed, and claims for cold fusion have not survived peer review to appear in mainstream journals.
Now Brian Clarke of McMaster University in Ontario, Canada, has found something that is not easily explained away.
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Researchers at SRI International, a private laboratory in California, carried out a cold fusion experiment 鈥� passing a current through heavy water using palladium electrodes 鈥� and claimed to see more heat produced than could be explained by the electric power used. They then sent their electrodes to Clarke for analysis. He discovered that they contained more than 1015 atoms of tritium, a heavy radioactive isotope of hydrogen.
鈥淭here鈥檚 no question of the tritium being real,鈥� Clarke told New 杏吧原创. 鈥淣o explanation鈥�
Although this is more tritium than you would expect to find in a palladium electrode, it is far less than would be needed to account for the amount of heat produced during the experiment. A spokesman for the UK Atomic Energy Authority鈥檚 Culham Laboratory who has seen Clarke鈥檚 analysis said the small amount of tritium 鈥渋ndicates it鈥檚 an electrochemical effect鈥� -that the heat is produced by the making or breaking of chemical bonds rather than the fusing of nuclei.
鈥淚 have no explanation of how the tritium was produced,鈥� Clarke told New 杏吧原创.
Michael McKubre, who performed the SRI experiments, says: 鈥淚 am not convinced it鈥檚 a fusion process, but it鈥檚 definitely a nuclear process.鈥�
Clarke also investigated similar experiments led by Yoshiaki Arata of Osaka University, Japan. Arata鈥檚 team claimed to have detected an excess of helium-3 and helium-4 isotopes following the heavy water electrolysis. But Clarke鈥檚 analysis revealed no excess.
Journal reference: Fusion Science and Technology, (Vol 40, p 147, 152)
