The ongoing crisis in Japan comes as a new federal report is calling into question the self-regulatory practices of nuclear plants in the United States. According to the U.S. Nuclear Regulatory Commission’s inspector general, over a quarter of U.S. nuclear power plants have failed to properly report equipment defects that could threaten the safety of their reactors. At least 28 percent of the nation’s 104 nuclear plants appeared unaware of rules requiring their disclosure of any safety flaws, even if no actual lapses occur. Experts say the lack of disclosures could make it more difficult for nuclear operators to uncover flaws in the equipment they have in common with other facilities.