Signs of the times: 'Keep out' for millenniums Nuclear waste warnings have to last 10,000 years

October 05, 1992|By Los Angeles Times News Service

ALBUQUERQUE, N.M. -- 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, or WIPP, near Carlsbad, N.M.

The Department of Energy 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, WIPP's 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 Association in Washington. "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. WIPP's 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 WIPP entrance shaft.

The B-team, whose report was edited by Mr. 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. "It would be a mistake to try and scare future people, because in the past that hasn't paid off," Mr. 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 indicate when WIPP was built.

The next step in the $200,000 study calls for recommendations to be circulated for peer review.

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