Vermont Yankee: What to do with spent fuel?

Vermont Business Magazine, Aug 01, 2004 by McQuiston, Timothy

At this ppint, Yucca Mountain is the only option for a permanent repository.

Yucca Mountain lies about 100 miles northwest of Las Vegas. The geological event that created this ridge - an eruption 20 miles north of Yucca - occurred 1113 million years ago. This makes it one of the youngest geological formations in the continental United States.

The basic concept behind siting nuclear waste at Yucca Mountain is that it is a dry, remote site that is on federal land. Water is the principal foe of secure containment. The test tunnel, like the separate 75-mile tunnel to come, is 1,000 meters under the summit and 1,000 meters above the ground water.

Construction on the permanent tunnel would begin in 2007 or 2008.

Tests that forced thousands of gallons of water from the summit - many times the annual rain fall of about six inches - indicated that very little water permeated the rock and seeped down into the tunnel.

A kind of subway system with tunnels that dead-end would hold the metal containers storing the spent fuel. The spent fuel pellets them selves also would be sealed before being contained.

The heat generated by the spent fuel would cause the tunnel to heat up to 400 degrees Fahrenheit. According to Richard Kovach, a field test manager from Los Alamos National Laboratory in New Mexico, who works at Yucca Mountain, a thermal test revealed that it took a five-years for a tunnel to drop from 400 degrees to 160 degrees. He estimated that in an actual tunnel with spent fuel, it would take about 1,500 years for the tunnel to cool down below the boiling point.

The safety standard used for the federal repository has been for containment to be secure for 10,000 years.

Opponents say Yucca Mountain is the wrong type of geologic formation because the rock is porous. Once the tunnel cools, the water will condense and the metal will corrode, and eventually, maybe within a couple of hundred years, the containment will be breached, opponents have argued. Opponents also bring up the relative youth of the geology to suggest that Yucca is not safe enough.

Proponents, meanwhile, sight evidence that, in fact, there has not been any recent history of seismic activity. As far as the potential volcanic activity, as indicated by the cinder cones, the fault line runs parallel to the California border to the west, not toward Yucca Mountain.

Robert Loux, the Director of the Agency of Nuclear Projects in the Nevada governor's office and an opponent of the project, said the fact that the containment is above the water table is part of the problem, not part of the solution. He said containment would be more secure either sitting on the desert floor or sitting in water in the absence of air.

Opponents like Loux argue that federal and local officials should be patient and find the best sight. He said on-site storage should be safe for 100 hundred years or more, providing time to find the perfect site.

"The long term storage of spent fuel is by law the responsibility of the Department of Energy," Rob Williams said. "Congress has directed -the DOE to focus on Yucca Mountain for permanent disposal. All spent fuel storage at Vermont Yankee is temporary. It is common sense that it is far better to have spent fuel stored deep underground in a dry desert at the edge of the old nuclear testing grounds at Nellis Air Force Base than it is to have it in Vernon for the long term."