IN 1976 a giant coring device mounted to a ship plunged repeatedly into the bottom of the Pacific Ocean, three miles below the surface, bringing up 100-foot-long tubes of mud and clay with the consistency of peanut butter. The primeval muck told a tale of geologic serenity. Sediment records from the cores indicate that the region -- roughly 600 miles north of Hawaii and spanning an area four times the size of Texas -- has been tranquil for 65 million years, unperturbed by volcanic activity or by shifting of the earth's tectonic plates. Charles Hollister, a geologist and senior scientist at the Woods Hole Oceanographic Institution, saw even more when he gazed at the thick dark ooze. He saw what might prove to be the perfect place to sequester our high-level nuclear waste -- the most potent and intensely radioactive by-products of military or civilian enterprise.
It's an intriguing vision, and one that in principle still holds great promise. Yet the concept of "sub-seabed disposal," first suggested by Hollister in 1973, has been undercut by a series of political blunders. A decision later this fall at a meeting in London sponsored by the International Maritime Organization, and a bill before Congress at this writing, may kill the idea -- possibly the best solution yet advanced to the nuclear-waste problem -- before society has had a chance to judge its true potential.
Hollister first hit upon the notion of sub-seabed burial twenty-three years ago, at a small social gathering in Washington, D.C. There he met William Bishop, a chemist at the Sandia National Laboratories, in New Mexico, who described the problems associated with a proposed nuclear-waste repository in Lyons, Kansas. "I immediately thought of the clays in the deep-sea floor, which I knew, from previous studies, clung tenaciously to the radioactive particles that had settled there as a result of atmospheric nuclear testing," Hollister recalls. He and Bishop stayed up all night discussing the idea, and a month later Hollister made a pitch to officials at Sandia, whose interest was piqued.
Next Hollister brought biologists, physicists, and oceanographers to Sandia to see if they could "destroy" the idea in what he calls the "biggest shootout since the OK Corral." He says, "If we could find out it was a stupid idea at the outset, it would save us a lot of time and money." But rather than shooting down the concept, many of the scientists told Hollister they'd like to work with him on it. A sub-seabed research program was initiated in 1974, with financial backing from Sandia; within a few years it had grown into an international effort involving ten countries and 200 scientists, under the auspices of the Paris-based Organization for Economic Cooperation and Development. This collaboration led to the core-sampling expedition that demonstrated the stability of the region underlying the North Pacific floor. Hollister points out that the Pacific site he and his colleagues explored twenty years ago is not unusual, geologically speaking. "About a quarter of this planet is covered with geology that is appropriate for this solution," he says.
Experiments conducted by this international team of scientists from 1974 to 1986 support Hollister's opinion that the sticky mud and clays that blanket the mid-ocean basins may provide the best burial grounds yet proposed for nuclear waste. These tests suggest that if waste canisters were deposited just ten meters below the ocean floor, any toxic substances that leaked out would be bound up by the clays for millions of years. Deeper interment, at 100 meters or more, could easily be managed, providing an even greater margin of safety. "The stuff sticks to the mud and sits there like heavy lead," Hollister maintains. "Nothing's going to bring it into the biosphere, unless we figure out how to reverse gravity."
If he's right, and the proposed technique could end the worldwide radioactive-waste problem that has been building up for the past fifty years, why has almost nobody in this country heard about it? The answer to this question -- along with the roots of many of the problems plaguing current U.S. nuclear-waste-disposal efforts -- can be traced to a 1986 decision by the Department of Energy which cut off research funds for sub-seabed and other disposal alternatives, so that the agency could focus exclusively on developing a land-based geologic repository for high-level wastes; a year later it settled on Yucca Mountain, Nevada. The timing was unfortunate: ongoing sub-seabed experiments were canceled in spite of encouraging results and after much experimental apparatus had already been built.
The federal government had a change of heart in 1987, when Congress passed amendments to the Nuclear Waste Policy Act which, among other things, established the Office of Subseabed Disposal Research within the DOE. The director of this office, Walter L. Warnick, was asked to create a consortium of university investigators and devise a long-range research plan. But a couple of months after Warnick had enthusiastically begun, the congressional committee that controlled appropriations strongly discouraged the Energy Department from spending any money on the program. With access to sub-seabed research funds blocked, Warnick shifted his attention to acid rain and global-warming issues. The Office of Subseabed Disposal existed in name only until this year, when it was abolished altogether.
Warnick was disappointed by the final decision, although he recognizes that it was effectively made about a decade ago, when the DOE and Congress chose the Yucca Mountain alternative and "put all their eggs in that basket." The judgment, he adds, was made on pragmatic, rather than technical, grounds. "It merely reflected the feeling that land-based-disposal technology was more advanced at the time." But from a technological point of view, he says, "sub-seabed disposal is a fascinating concept that offers many advantages, perhaps the foremost being that wastes would be deposited at some of the most geologically stable places on earth." What's more, "all the research that has been done on this option since 1974 points to no insurmountable obstacles" -- an assessment, Warnick says, that is widely accepted within the Energy Department.