Moving rapidly to put new leadership atop the unsettled Nuclear Regulatory Commission, President Obama has nominated George Mason University professor Allison M. Macfarlane as a commissioner and also said he would name her as the NRC’s new chair.

Macfarlane was a member of a blue-ribbon panel charged with recommending ways to deal with the growing problem of how to dispose of the country’s nuclear waste.  Since 2006, Macfarlane has been an associate professor of environmental science and policy at George Mason, in Fairfax, Va.

The May 24 White House announcement comes during a turbulent time for the NRC, which is charged with overseeing safety at the country’s nuclear-power reactors and licensing new units.

At the center of the storm is Gregory B. Jaczko, the commission’s chairman since 2009, who on May 21 announced that he planned to resign his post when a successor is confirmed. Jaczko, a Democrat, is a former aide to Senate Majority Leader Harry Reid (D-Nev.) and has been viewed as taking an aggressive regulatory stance toward the industry.

But last fall, he became the focus of an intramural controversy. The panel's other four commissioners—two Democrats and two Republicans—took the highly unusual step of criticizing Jaczko in a joint letter to then-White House Chief of Staff William Daley.

In their letter, which was sent in October but became public in December, the four officials said they had “grave concerns” about Jaczko’s “leadership and management practices” and said his actions “are causing serious damage” to the NRC.

Jaczko, testifying at follow-up congressional hearings with his fellow commissioners—and critics—late last year, said he did get passionate about advancing nuclear safety but denied allegations that he bullied NRC staffers or withheld information from other commissioners.

Contributing to the far-from-placid picture at the NRC, the term of another commissioner, Kristine L. Svinicki, a Republican, is due to expire on June 30. Obama renominated her on May 8 and GOP leaders have been pressing for quick action on her nomination.

The announcement of Macfarlane will allow the Senate to take up her nomination and Svinicki’s at the same time.

In fact, shortly after the White House announcement, Senate Environment and Public Works Committee Chairman Barbara Boxer (D-Calif.) said that she planned to hold confirmation hearings on Macfarlane and Svinicki in June.