Reid, who is the Senate majority leader, signaled last month he would block Svinicki's confirmation until the White House agreed to keep Jaczko as well.

Jaczko, a native of upstate New York who holds a physics doctorate from the University of Wisconsin, worked as Reid's science and Yucca Mountain adviser before he joined the NRC in 2005.

Reid has led Nevada's official opposition to the Yucca project, working to cut its budget in Congress and block any bills that would help it advance.

As evidenced by his campaign for Jaczko and by reports about others he is considering for upcoming NRC vacancies, Reid seems to be positioning for the licensing process as well.

Since becoming a commissioner, Jaczko has had few opportunities to opine on the Yucca project but generally has argued in favor of tougher safety rules for nuclear reactors. The NRC licenses nuclear facilities and regulates the handling of nuclear materials.

Sen. James Inhofe, R-Okla., who supports a Yucca repository, has expressed reservations about extending Jaczko's term. A spokesman said Friday he did not know if Inhofe was aware of the White House agreement or what he would think about it.

The Energy Department has said it would submit a repository application to the NRC by the end of next June. That kicks off a licensing process that by law would last three or four years although many believe it will take longer than that.

Reid's office declined to comment on a further report that the senator is looking favorably on Allison Macfarlane, an environmental science associate professor at George Mason University, to fill any upcoming vacancies at the NRC.

Macfarlane, previously a research associate at the Massachusetts Institute of Technology, co-edited a 2006 book about Yucca Mountain titled "Uncertainty Underground."

Macfarlane testified before the Senate in March 2006 that it will be difficult for the Energy Department to conclude with any certainty that Yucca Mountain is suitable as a repository site.

Reid has made the same points in trying to get the project stopped or slowed in Congress.