Science & Ideas 6/26/00
Strange bedfellows below the desert
Will cosmology and nuclear dumping mix?
By Charles W. Petit
CARLSBAD, N.M.-Something seemed akilter last week in a briny plain 26 miles from this town of 28,000 people in New Mexico's arid southeast corner. Several dozen astronomers and physicists showed up in search of a low-radiation home for a large, underground lab. They were in hot pursuit of the wild physics behind exploding stars, black holes, and gravity-with methods that work best deep inside the Earth. Their specific quarry: exotic particles like neutrinos spawned in the depths of space. To cut costs they needed a place where most of the digging has already been done.
A hole is what drew them here. But low radiation? This hole is called WIPP, shorthand for the U.S. Department of Energy's Waste Isolation Pilot Plant, the world's first underground repository for radioactive garbage. In March last year WIPP's operators, after $2.5 billion in expenses and two decades of legal wrangling, launched this grave for material contaminated by the making of nuclear warheads. Some 6.2 million cubic feet of such waste will be left in rooms along 50 miles of WIPP corridors. Within a century the salt, creeping under geologic pressure, will seal the drums in. Some contents will be radioactive for a half-million years.
The 45 visitors donned hard hats with miners' lights on front. Passing through airlocks, they loaded into a steel cage elevator able to carry 40 tons at a time. Five minutes later they were 2,150 feet down, hopping into golf carts for a tour of a growing network of caverns, all carved into white and pink rock salt left by a drying sea 225 million years ago. They were clearly pleased by repeated assurances that, money permitting, almost any volume of new caverns could be carved for them, too.
Calming fears. Roger Nelson, DOE's chief scientist at WIPP, hosted an accompanying, three-day workshop at the town's meeting center along the Pecos River. He presented data showing that despite its function, the facility's radiation is much lower than most places with no waste. Salt has a fraction of the natural radioactive uranium and thorium in ordinary rock. The nuclear garbage is shielded by its containers and will be half a mile or more from any research areas. WIPP management hopes, he freely concedes, that a project that demands low radiation will allay public worry about the waste.
University of California-Los Angeles physicist David Cline whispered to 79-year-old Alfred Mann that it could be his dream come true. A University of Pennsylvania physicist, Mann has been plotting for decades to persuade the U.S. to build an underground lab far superior to the Super-Kamiokande Observatory in a Japanese zinc mine, or Gran Sasso National Laboratory in a highway tunnel through a mountain east of Rome, or the Sudbury Neutrino Observatory in a Canadian nickel mine.
Carlsbad would win, too. Indeed, civic leaders toasted the scientists, knowing they could bring not only scientific luster but also jobs to a town where mining and oil work is getting scarcer. Still, hurdles are high. Costs could be a billion dollars or even more. Some in the energy department fear that extra labs could invite lawsuits from public-interest groups worried that science might displace safety.
The astronomers came out with stars in their eyes. Chang Kee Jung, associate professor of physics at the State University of New York-Stony Brook, plumped for something really big, an anchor project that will take decades to run its course. His idea is a sensor-lined, 650,000 ton tank of purified water-hundreds of feet on a side and 13 times bigger than the world's largest existing detector. It would intercept the wispy neutrinos streaming from the sun and from distant, exploding stars. The detector might even determine whether protons and other basic building blocks of atoms are very slowly evaporating. Other scientists talked of hundreds or even thousands of tons of lead and iron, or smaller detectors of germanium, tellurium, or argon. Such a lab could even detect so-called dark matter, the elusive stuff thought to account for most of the universe's mass.
Jung, a South Korean-born New York physicist, was dressed for success. "I got my bolo tie on, my cowboy boots on," he declared. "I'm ready to move in."