Thursday, July 17, 2003 | 8:41 a.m.
The Energy Department plans to answer at least 190 key technical questions out of 293 before submitting a license application for a Yucca Mountain high-level nuclear waste repository, officials said.
That's about 65 percent of the outstanding scientific and technical questions the Nuclear Regulatory Commission wants the Energy Department to answer before it applies to build the repository, Joseph Ziegler, acting director for DOE's license application strategy, said Wednesday at a teleconferenced meeting of the groups in Washington and Las Vegas.
Of those issues, 41 are considered high-risk, Ziegler said. Another 92 issues are considered medium risk.
The unanswered technical questions have been a key point in Nevada's opposition to the nuclear dump. State officials cited statements by an independent review board that called scientific evidence supporting the site "weak to moderate."
Unless the NRC is satisfied that scientific information is complete, the commission could reject a license application from the Energy Department, which expects to submit one in December 2004, she said.
Janet Schuleter, chief of the NRC High-Level Waste Branch, invited the Energy Department to submit an example of its analysis of a technical issue later this year to ensure the department is doing rigorous analysis.
"It's a very challenging time in the program," John Arthur, deputy director of DOE's repository program, said during a second day of a quarterly meeting between the department and the Nuclear Regulatory Commission staff.
An example of a question that will remain a concern after license application is submitted is the probability of a volcano erupting through the repository.
If hot magma broke open and buried waste containers and reached the surface, radioactivity could be spread airborne in ash and in water after a rainfall.
Scientists have discovered a number of features just west of Yucca that could be evidence of volcanic activity buried under fill built up in the valleys over thousands of years. However, no scientific studies of the area have been attempted.
The DOE is planning to go into the field and drill into those volcanic centers, Ziegler said. In addition, the department plans to conduct aerial surveys to map the features. The work could take until 2005 or beyond.
"Either way, the work is going to go beyond the license application," Ziegler said.
Individual technical reports on threats from tornadoes and aircraft crashing into the repository while it is operating are planned, he said.
One issue that concerns the Nuclear Regulatory Commission is the threat of a nuclear reaction, Jack Parrott, NRC on-site representative in Las Vegas, said.
If spent fuel became too concentrated either in a shipping container or inside a buried waste container, a nuclear chain reaction could occur and cause metal containers to corrode and release radiation.
Yucca contractor Bechtel SAIC director John Mitchell said that studies on that issue had fallen behind due to budget cuts and other, more pressing issues. However, the DOE has asked Los Alamos National Laboratory experts to review the issue again.
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