Trying To Tame H-Bomb

By Philip Elmer-DeWitt

The claim was so spectacular that it was difficult to believe. News reports suggested that scientists might have achieved the world's first controlled, energy-yielding nuclear-fusion reaction -- a Holy Grail of physics for nearly 40 years. Moreover, the event had not occurred in one of the great national laboratories; it was the work of a pair of chemists operating on a shoestring budget and using little more than a test tube, a pencil-thin strip of metal and a car battery. Even more incredible was the assertion that this humble apparatus, fueled with a form of hydrogen found in ordinary seawater, had generated four times as much energy as it consumed. Could this be a new and virtually limitless source of cheap, clean power?

Thus late last month began a saga that continues to engage the attention of the scientific world as rarely before. The announcement by the two chemists, B. Stanley Pons of the University of Utah and Martin Fleischmann of the University of Southampton in England, while greeted with skepticism, also triggered a kind of free-for-all as researchers rushed to re-create the controversial experiment.

There were grounds for skepticism. While well respected in their fields, Pons and Fleischmann were far from the mainstream of fusion research. In addition, they had released their results in a manner that tended to cast suspicion on their claims, staging a press conference in Utah complete with television cameras. For several days researchers around the world were dependent on TV and newspapers for scraps of information about what could conceivably be the biggest science story of the year -- if not the decade.

Then the details of the experiment began to emerge. By an informal process known as "publication by fax," copies of a paper Pons and Fleischmann had prepared began to circulate from lab to lab. Next, one of the best-known figures in the field, physicist Steven Jones of Brigham Young University, announced that he too had achieved fusion in a jar, although, significantly, with far lower energy output. Even a pair of Hungarian scientists claimed to have carried out room-temperature fusion.

Last week, in an unusual move, a Dutch scientific journal pushed forward its schedule and published the report by Pons and Fleischmann. But at week's end the more prestigious British journal Nature had not yet decided whether to print their findings. The scientific community, while not at all convinced by the claim that the power of the H-bomb had finally been harnessed, was at least taking it seriously.

Nuclear fusion, the process that fires the sun, usually occurs when two atoms are squeezed together at very high temperatures to make one new atom. For example, two atoms of deuterium -- an isotope of hydrogen -- can be fused to form a helium atom and a neutron, releasing a sizable burst of energy. But before that can occur, deuterium nuclei generally need to be compressed with sufficient force to overcome their mutually repellent electrical charges. In H-bombs, that force is supplied by the detonation of an A-bomb. Conventional fusion techniques require giant magnets, powerful laser beams and particle accelerators. But none of these approaches have succeeded in generating more energy than they use.

The researchers at B.Y.U. and Utah took a different tack. Each constructed an apparatus similar to that used by ninth-grade science students to split water into hydrogen and oxygen. Instead of ordinary H2O, however, they used deuterium-rich heavy water (D2O). The scientists tried an array of exotic elements for their electrodes, including palladium, a semiprecious metal known to absorb large numbers of hydrogen -- and deuterium -- atoms. Plunged into a bath of heavy water and charged by a twelve-volt battery, a palladium rod will draw swarms of deuterium ions out of the liquid and into its latticelike crystal structure. There the ions lodge and gather in such concentrations that they supposedly overcome their natural repulsion and fuse. Just how that happens, even B.Y.U.'s Jones cannot say. "We have an experiment but not a theory," he confesses. "We have Cinderella, but we don't have her shoe."

Where the B.Y.U. and Utah teams part company is over how much energy such a device can produce. The startling claim by Pons and Fleischmann was that for every watt they pumped into their crude fuel cell, more than four watts came out. Jones, on the other hand, measured less than a trillionth of a watt. That is quite a gap. As he puts it, "It's the difference between a dollar bill and the national debt."

Why the huge discrepancy? One hypothesis, put forward by a group at England's Birmingham University, is that Pons and Fleischmann achieved fusion in an unconventional fashion. They had added lithium to their heavy water to make it a better conductor of electricity, and the lithium may have fused with the deuterium. This might account for the exceptionally high energy output.

Researchers are working feverishly to make sense of the fusion mystery. A British lab was swamped with requests from the public for advice on how to re- create the reaction, including one from a housewife who said she had already stockpiled a supply of heavy water. But even if the experiment is successfully duplicated, there is no guarantee that it will lead to a large- scale power plant. It could be decades before the commercial potential of the process, if any, is determined. For now, no one knows whether Pons and Fleischmann have simply made an embarrassing blunder, or if they are destined to become two of the most famous scientists who ever lived.

With reporting by David Bjerklie/New York and J. Madeleine Nash/Salt Lake City