The new head of scandal-tainted Los Alamos National Laboratory said Monday that science at the nuclear weapons design center remains exemplary and that its problems are all business related.

Interim Director Pete Nanos, brought in to enact reforms following allegations of purchasing fraud, equipment theft and cover-ups, said he would do his job in a way that doesn't disturb research.

"My challenge is to jack up the science and replace all the management and business controls on the bottom, then gently set the science back down on a new foundation without destroying that," he told The Associated Press in an interview.

He added that he feared the scandal, which has triggered investigations by the FBI, the Energy Department and Congress, would drive away senior scientists and inhibit the lab's ability to recruit new talent.

The scandal cost Director John Browne his job last month. The University of California, which operates the lab for the Energy Department, has assumed oversight of the audit office and other business operations.

Nanos also said the university was right to rehire two whistle-blowing investigators fired by the lab last fall.

"You don't turn away any source of data if it's credible data," Nanos said. "You work with it and fix it. So I think the university, in finding them credible, did exactly the right thing."

The university announced Friday it was rehiring investigators Glenn Walp and Steven Doran to help university President Richard Atkinson look into problems at the lab. The school also awarded the two back pay since November, when they were fired.

The two are expected to act as advisers to the university, detailing what they uncovered during last year's investigation. Doran said Monday that university officials told him and Walp that the two men would not return to the lab to continue their investigation.