Panel reiterates chances slim of volcano affecting Yucca

Benjamin Grove

Thursday, March 17, 2005 | 9:18 a.m.

WASHINGTON -- A Yucca Mountain oversight panel on Wednesday reiterated that the chances of a volcano disturbing the planned underground repository were tiny.

But the panel also cited a lack of scientific understanding about the effects of "igneous activity" at Yucca Mountain.

There are no clearly defined, long-term predictors of volcanic activity at Yucca Mountain, said William Hinze, a geophysicist and professor emeritus at Purdue University, and a member of a scientific panel of the Nuclear Regulatory Commission that advises the five-member commission on Yucca issues.

But most "scientifically acceptable" estimates predict that the chances of volcanic activity at Yucca are between 1 in 10 million and 1 in 100 million each year for the first 10,000 years of the repository, Hinze said.

"The chances are very, very, very small, but that doesn't mean we shouldn't understand, through comprehensive study, this issue," Hinze said after a regular commission briefing today.

Yucca Mountain critics generally agree with Energy Department officials who say a volcano is highly unlikely at Yucca, but they point to holes in department studies and findings. Those studies are part of the 20 years of research compiled by the department for an application for a license to construct Yucca. The department plans to submit the application to the NRC late this year.

The department aims to prove in the application that its research is sound and that Yucca is a safe place to construct a national high-level radioactive waste repository.

Hinze noted that small volcanos have occurred in the Yucca area over the past several million years. He said "important uncertainties remain" about the potential effects of volcanic activity on the repository and that more and better research is needed.

Scientists have had difficulty understanding how magma might behave in the tunnels of the repository, Hinze said. That makes it hard for scientists to know how magma would affect the high-tech metal waste containers stored in the tunnels.

Hinze said more realistic models were needed to demonstrate to the NRC just how magma would flow, and to demonstrate how contaminated ash and dust could be dispersed into the environment.

The panel plans to keep tabs on the issue for the NRC by reviewing the work of the San Antonio-based Center for Nuclear Waste Regulatory Analysis, which is conducting Yucca research for the NRC in preparation for the agency's review of the Yucca license application. The panel also may establish a working group of its own to study the issue.