More water is found in site for repository

Tuesday, April 24, 2001 | 11:23 a.m.

Water has moved quicker than expected -- more than 6 feet in two months -- through tiny fractures inside Yucca Mountain's volcanic rock, Energy Department scientists said during a tour Monday.

Yucca Mountain, 90 miles northwest of Las Vegas, is the only site being studied to bury 77,000 tons of nuclear reactor and weapons waste. Water is a concern because the area's mineral-laden ground water could corrode containers holding the waste, releasing radioactivity into the environment.

The DOE predicted that radiation in ground water would move a fraction of an inch at most in a year and not move off the site in 10,000 years. One criterion for the repository's approval is ensuring that contaminated ground water will not reach the nearest populated area, Amargosa Valley, 12 miles away.

Federal scientists downplayed the significance of the water.

"We've known there was water in the mountain since the first borehole was drilled there in 1978," Yucca Mountain project manager Russ Dyer said. He said the water was from condensation, not the mineral-laden ground water.

But Nevada officials, who oppose burying the commercial and defense wastes at Yucca, remain concerned.

"Ground water is the most important thing at the site," said Robert Loux, executive director of the Agency for Nuclear Projects, a state agency that oversees DOE's work at Yucca Mountain.

"Ground water is the way radiation will escape from the repository," Loux said. "It is clear (DOE officials) do not have a handle on how much water is inside the mountain or how fast it moves."

Federal scientists believe the water they collected began as vapor inside tiny cracks of the mountain's volcanic ash layers.

The latest finding came from an experiment that heats rock to water's boiling point to determine how the mountain will react under the heat expected from radioactive waste.

The heat apparently drove the vapor to cooler rock, where it condensed, scientists say.

Up to five gallons of water were recovered in an air duct 6 feet from the heater, DOE scientist Mark Peters said.

The heat test is one of several studies to determine the path of water through the mountain and how fast it travels. If water has invaded the repository level, 1,000 feet below the surface, in the last 10,000 years, the site could be disqualified as a dump.

The water table at Yucca Mountain is 1,000 feet lower than the repository site.

Chemical tests on the water indicate it came from condensation, not liquid tainted with minerals from the mountain, Dyer said.

Steve Frishman, technical coordinator, went underground on the tour requested by Rep. Shelley Berkley, D-Nev.

"The state has maintained all along that water moved through fractures and earthquake faults faster than the DOE was predicting it would," he said.

It was Berkley's first trip to the mountain. She has consistently opposed any storage or permanent burial of radioactive wastes in the mountain.

The daylong visit did not convince her the repository project was safe, she said.

"I am still not convinced that that mountain doesn't hold an excessive amount of water that will compromise the integrity of the storage containers buried there, nor that anyone can guarantee that the mountain will be safe at 10,000 years or even 50 years from now," Berkley said after the tour.