AMERICAN ALBUM : Composing a message for the ages: ‘Keep Out!’ : Scholars seek a way to warn future civilizations about our radioactive burial grounds.

How do you warn future generations that the contents of a vast underground nuclear waste repository will remain dangerously radioactive for the next 10,000 years?

When Sandia National Laboratories asked 13 experts to wrestle with that question last fall, it was not just an academic exercise. The government has long pondered how to mark the site of the Waste Isolation Pilot Plant near Carlsbad, N. M.

The Energy Department hopes one day to fill caverns carved from subterranean salt beds with 300,000 barrels of plutonium-contaminated waste from America’s nuclear weapons program. The repository could operate for 30 years before it closes sometime in the 21st Century.

Although the drums will be sealed in salt 2,000 feet underground, designers worry that a gusher of radioactive brine could spew out if someone accidentally drills into the formation.

The experts were asked to devise a system of warning markers, as well as estimate the likelihood that intruders might penetrate the site. Panel members included anthropologists, astronomers, a linguist, a geologist, materials scientists, a mathematical psychologist, an architect and an artist.

“All the people on the project were just fascinated by the idea of designing what could be the longest-lasting human artifact,” said David Givens, an executive with the American Anthropological Assn. in Washington, D.C. “Nobody else in history that I know of has been deliberately charged with sending a message that far into the future.”

A marking system must speak louder than words and should be redundant, in case elements are damaged or removed, the experts agreed. Markers also should be consistent with those used at other nuclear waste repositories around the world, incorporating written messages in multiple languages and 30-foot-high protective earthen berms.

The panel divided into two teams, which made a host of suggestions on how to post a “Keep Out” sign for the ages.

The six-member A-team favored menacing stone monoliths or earthworks to repel those tempted to tamper with the sealed waste-isolation entrance shaft, as well as anyone who might drill for oil or gas.

The team argued for “archetypal” forms that communicate across cultural barriers, such as a landscape of giant concrete thorns, a field of stone spikes or spikes bursting through a grid. Other ideas included marking the site with off-putting earthen berms, massive piles of rubble or huge, forbidding stone blocks.

The team recommended against geometrical shapes representing beauty and perfection, such as pyramids and obelisks, in favor of crude, dread-inspiring forms that say “stay away.”

Although detailed written warnings could be engraved in rock shelters, Michael Brill, an architect and professor at the State University of New York in Buffalo, said the A-team opposed using pictographs to try to communicate the danger posed by radioactive waste because there is no telling how culture will have changed in 10,000 years.

“Almost every pictograph you can construct is ambiguous,” he said.

The B-team, whose report was edited by Givens, suggested building the giant earthen berm in the shape of a designated warning symbol, perhaps the trefoil emblem currently used to indicate radioactivity.

A ring of granite monoliths engraved with warnings could be erected within the earthworks, while a central granite-roofed structure could house more extensive written descriptions of what is buried there.

The team rejected the idea of sinister earthworks because people can be contrary. “It would be a mistake to try and scare future people, because in the past that hasn’t paid off,” Givens said.

The B-team was more optimistic about using pictograph warnings. It also suggested engraving in stone the periodic table of the elements to show which wastes are stored.

Another idea is to include a chart showing how far the North Star will have moved from its present location in 10,000 years to give future visitors an idea of when the pilot plant was built.

The next step in the $200,000 Energy Department-funded study calls for recommendations to be summarized and circulated for peer review. Portions of the study will probably form the basis for the final marker design.

Nuclear Graveyard: Keep Out

Experts are trying to design the ultimate “Keep Out” sign, a marker to warn away future generations 10,000 years from now. Here are three of the proposed designs. RUBBLE LANDSCAPE

Exploded and piled stone Outer rim of caliche stone is dynamited and bulldozed into the center. When the center is raised, the rim fills with sand, making it hard to walk on or bring machinery onto. FORBIDDING BLOCKS

Massive, black-dyed, blocks. These blocks would be placed very close together, making the area difficult to live in or farm in because of their spiked exterior and hot interior. STONE SPIKES

Randomly spaced basalt spikes, 70 feet high with a slight slope. From a distance, the basalt spikes would look like a landscape of thorns, which would give the feeling of death or fear.

Source: Department of Energy