Thu, Jan 26, 2006 (7:53 a.m.)

Tests of trucks carrying low-level nuclear waste for burial at the Nevada Test Site found no violations of federal radiation exposure levels, state scientists have concluded.

The Desert Research Institute, a nonprofit division of the Nevada System of Higher Education, earlier this month released the results of a study of radiation exposure from the shipments, an issue of concern to communities along the truck routes.

Scientists screened 1,102 trucks, nearly half of all shipments, during the study period of February to December 2003. The tests were conducted at an area at the Test Site, 65 miles northwest of Las Vegas. Participation was voluntary.

The study was unusual because it measured actual radiation, said David Shafer, executive director of the institute's Frank H. Rogers Center for Environmental Remediation and Monitoring.

"Most studies of radiation exposure from truck transportation are based on calculations of potential exposure," Shafer said. "The study was designed to help answer the question, 'What do the trucks really measure?' "

The researchers looked for gamma radiation that could have passed through the walls of waste containers. The monitoring equipment was placed roughly three feet from the trucks' sides at about the height of a man's chest.

Tests on 70 percent of the trucks found no radiation levels above the amount naturally occurring in the environment, Shafer said.

Of the remainder, "no trucks monitored came close to exceeding" the U.S. Transportation Department's standards, Shafer said.

He acknowledged that for some people, even those trace readings "represent some type of risk."

The National Nuclear Security Administration spent $235,000 over three years for the study, agency spokeswoman Kelly Snyder said.

Since 1980, more than 27 million square feet of low-level nuclear waste has been shipped to the Test Site for shallow land burial. Most comes from sites run by the Energy and Defense departments.

Low-level waste -- typically waste such as construction debris, soil or equipment that may have been tainted by radiation -- is not to be confused with the far more dangerous "high-level" waste, such as highly radioactive spent uranium rods from nuclear power plants. The proposed repository at Yucca Mountain would be a national repository for high-level waste.

Low-level waste is not shipped through the Las Vegas Valley.

The study should offer some comfort to wary residents in rural areas who have voiced concerns about low-level waste shipments over the years, Shafer said.

Still, some residents may continue to worry, despite indications that the shipments are safe.

"It's fair to say that a lot of the trucks have very low levels," he said. "But for some people, any exposure above background radiation is a risk."

Mary Manning can be reached at 259-4065 or at manning@lasvegassun.com.

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