WASHINGTON - Moving quickly to stem a controversy, President Barack Obama on Thursday nominated an expert on nuclear waste to lead the federal agency that regulates the nation's nuclear power plants.

Allison Macfarlane, who served on a presidential commission that studied new strategies to manage nuclear waste, would replace Gregory Jaczko as head of the Nuclear Regulatory Commission. Jaczko announced his resignation Monday after a tumultuous three-year tenure in which he pushed for sweeping safety reforms but came under fire for an unyielding management style that fellow commissioners and agency employees described as bullying.

A White House spokesman said Obama believes Macfarlane is the right person to lead the commission, calling her a highly regarded expert who has spent years analyzing nuclear issues.

Macfarlane "understands the role that nuclear power must play in our nation's energy future while ensuring that we are always taking steps to produce this important energy source safely and securely," White House spokesman Clark Stevens said.

Stevens called the NRC crucial to protecting public health and safety and said Obama hopes the Senate considers her nomination quickly.

Macfarlane, 48, an associate professor of environmental science and policy at George Mason University in Fairfax, Va., wrote a book in 2006 that raised technical questions about a proposed nuclear waste dump at Nevada's Yucca Mountain.

Senate Majority Leader Harry Reid, D-Nev., who is the leading congressional opponent of the Yucca site, praised Macfarlane as someone who will make nuclear safety a top priority. Macfarlane's education and experience, especially her service on the blue-ribbon commission on nuclear waste, make her qualified to lead the NRC "for the foreseeable future," Reid said in a statement.

Reid said he continues to have concerns about Republican Kristine Svinicki, who has been nominated by Obama for a new term on the commission, but added that he believes Svinicki and Macfarlane should be considered together, continuing a recent Senate tradition of considering NRC nominees from opposing parties at the same time.

Svinicki, a nuclear engineer and former Senate GOP aide, was among four NRC commissioners who publicly criticized Jaczko's management style last year. The commissioners - two Democrats and two Republicans - sent a letter to the White House last fall expressing "grave concern" about Jaczko' s actions, which they said were abusive and "causing serious damage" to the commission.

No disciplinary action was taken against Jaczko, who has strongly denied the allegations.

Jaczko, a Democrat, announced his resignation ahead of a potentially blistering report due out soon from the agency's inspector general, which has been investigating Jaczko's actions for more than a year.

A former Reid aide, Jaczko led a strong response to the nuclear disaster in Japan and was a favorite of industry watchdogs, who called his emphasis on safety a refreshing change from previous agency chiefs who were close to the nuclear industry or who came from it.

But scientists, fellow commissioners and many rank-and-file staffers said Jaczko had created a chilled working environment at the NRC, which oversees safety at the nation's 104 commercial nuclear reactors.

The Nuclear Energy Institute, an industry group, called Macfarlane "an active contributor to policy debates in the nuclear energy field for many years" and urged the Senate to confirm her nomination as soon as possible.

"It would not serve the public interest to have her nomination linger," the group said. "We urge the Senate to confirm both Commissioner Svinicki and Professor Macfarlane expeditiously."

Sen. Barbara Boxer, D-Calif., chairwoman of the Senate Environment Committee, said Macfarlane's background and experience demonstrate a strong commitment to safety - a commitment she called especially important in the wake of the nuclear disaster at Japan's Fukushima Dai-ichi plant.

Boxer said she will schedule a joint hearing on the two NRC nominees in June.

Per Peterson, a professor of nuclear engineering at the University of California, served with Macfarlane on the nuclear waste commission, which was appointed by the Obama administration to make recommendations on how the nation should store and dispose of more than 71,000 tons of radioactive waste at dozens of sites across the country.

"I think she will be effective in leadership" of the NRC, "mainly because she listens," Peterson said of Macfarlane.

In a 2009 interview with Technology Review, Macfarlane acknowledged that most of the objections to the never-completed Yucca Mountain site were political, but added: "The technical objections are serious and real."

The area near Yucca Mountain is seismically and volcanically active, she said, adding that spent nuclear fuel could be stored safely at nuclear plants for decades.

The presidential panel recommended that the government start looking immediately for an alternative to Yucca Mountain. The report also recommended that responsibility for managing nuclear waste be transferred to a new organization, independent of the Energy Department.