Top nuclear regulator resigns amid GOP criticisms WASHINGTON -- The chairman of the Nuclear Regulatory Commission who was championed by watchdogs for his cautious approach to nuclear power but criticized by Republicans in Congress for an overly hard-charging style has announced he will step down. Gregory Jaczko, who led the commission's efforts to protect Americans in Japan during the nuclear crisis at Fukushima and played a key role in fighting the nuclear waste repository at Yucca Mountain as a former top aide to Sen. Harry Reid (D-Nev.), the majority leader, came under scrutiny for what critics called an overbearing management approach at the agency. His resignation is effective upon confirmation of his successor. Jaczko "dedicated his tenure to improving the safety of nuclear energy," Reid said in a statement. His work toward a safe and effective nuclear energy policy has left Nevada and the nation more secure. Critics, though, have targeted Jaczko for dismissal after a report from the GOP-led House Oversight and Government Affairs Committee found "his management style and aggressive behavior simultaneously eroded the collegial structure" at the NRC. "The only thing surprising about his resignation is the fact that the Obama administration has remained silent for more than a year after allegations of Jaczko's offensive behavior surfaced," said Kentucky Sen. Mitch McConnell, the Republican leader. The open chairman's post on the five-member commission will likely set off a partisan scramble. Republicans are pressing the Senate to reconfirm the nomination of Commissioner Kristine Svinicki, whose term expires June 30. The Union of Concerned Scientists, a watchdog group, said Jaczko's departure leaves a "big hole" at the agency. The group urged the White House to select a new chairman "as committed as Jaczko is to protecting public health and safety." First confirmed to the commission in 2005, Jaczko was appointed chairman by President Obama in 2009. His term expires in June 2013. Original source: Top nuclear regulator resigns amid GOP criticisms