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More about Yucca Mountain Click on the image for an enlargement. Illustration by David Stroud.

Saturday, July 06, 2002
Copyright © Las Vegas Review-Journal

Symbols send danger alert

Scientists creating Yucca warning signs to last 10,000 years

Scientists designing the Yucca Mountain nuclear waste repository must account for future changes in technology, climate and geology. But they're counting on one constant over the next 10,000 years: the way people express danger.

In making plans to entomb the nation's spent nuclear fuel 100 miles northwest of Las Vegas, the federal government wants to keep future would-be explorers from tampering with the waste.

Project officials envision etching on 25-ton granite monoliths distraught faces patterned after artist Edvard Munch's 1893 painting, "The Scream." They hope the images will remain intact over the millennia to illustrate the horror of what could happen if someone retrieved metal canisters holding a combined 77,000 tonĀs of decaying fuel pellets buried deep within the mountain.

To complement the artwork, they will write in at least six languages -- English, French, Arabic, Chinese, Spanish, and Russian -- words that express the phrase, "Caution: Biohazardous waste buried here."

Such a plan was crafted for the Waste Isolation Pilot Plant near Carlsbad, N.M., where the nation's plutonium-tainted, so-called midlevel nuclear waste is being put in caverns in a 2,000-foot-thick salt formation.

Department of Energy scientists were pursuing a similar plan for warning markers at Yucca Mountain. But when budget cuts curtailed the work, they opted to follow the course set for the Waste Isolation Pilot Plant, an agency spokesman said.

Roger Nelson, the chief scientist at the Waste Isolation Pilot Plant, said the warning plan approved by the Environmental Protection Agency is a conceptual design. It will be developed gradually until construction begins on permanent markers in about 35 years.

By then, Nelson said, the most robust materials will be available for an array of surface and subsurface markers encrypted with the most simple expressions of danger. Candidate materials include granite, basalt and ceramics. Magnetic signage also is being considered.

"There is no way we can predict what the language structure will be 10,000 years into the future," he said.

He said the permanent marker work is based on the notion that future generations will retain an institutional memory. In theory, future travelers to nuclear waste burial sites will seek to understand the meaning of the messages much like archaeologists try to interpret the intentions of the creators of England's Stonehenge and Egypt's pyramids.

"The data point is that civilization has always gotten smarter, not dumber," Nelson said. "You will say people will be smarter in the future. Will they understand these languages? The answer is yes."

Like Stonehenge and the pyramids, the spiked monoliths atop the perimeters of the planned Yucca Mountain repository and the Waste Isolation Pilot Plant could attract the curious and create a nuisance.

"The panel of experts debated that question as well. Some said, 'Yeah, it will be an attraction,' " Nelson noted. But he said they concluded that signs, like locks, are built for honest people, and only honest people obey signs.

To reach the materials, intruders would have to sustain a substantial effort, digging or drilling 1,000 feet to 2,000 feet down from the surface. "So, if you're an honest person, you'll obey the signs," Nelson said.

Former Sandia National Laboratories engineer Kathleen Trauth, who coordinated the effort to design permanent warning markers for the Waste Isolation Pilot Plant, said a goal of the project was to use simple symbols and words for broad, accurate and comprehensive communications.

"One way of communicating the nature of risk is through the human face," she said. "It's a means of communication that goes across cultures and languages."

Trauth said the experts decided to use a multi-language approach, because no one can predict with absolute confidence what language people will speak in 10,000 years.

Ten thousand years is the regulatory requirement for containing high-level nuclear waste, even though Nevada scientists who oppose the Yucca Mountain Project note peak doses from some of the decaying materials won't occur until much later, in the 300,000-year to 800,000-year time frame.

"If you had some sort of key, you could unlock languages," said Trauth, assistant professor for civil and environmental engineering at the University of Missouri. "There are ways of writing very clear without a lot of idioms to make it very clear in the future."

The object is to relate symbols, experiences or figures that are very easy to interpret, she said.

The U.S. Senate is expected to vote later this month on a resolution to override Gov. Kenny Guinn's veto of the Yucca Mountain Project. A majority vote of the Senate would formally approve the repository plans, although Nevada officials plan to fight the project in court.