The Nuclear Regulatory Commission should rethink how it sets evacuation zones around U.S. reactors instead of basing such crucial safety zones on "arbitrary mileage destinations," an expert panel said today.

The American Nuclear Society's report -- released three days before the one-year anniversary of Japan's nuclear disaster -- outlines safety recommendations for U.S. power plants based on lessons learned from the earthquake and tsunami that crippled the Fukushima Daiichi nuclear plant.

The panel of nuclear scientists and a former NRC chairman found the agency's oversight adequate to protect public health and safety, but they expressed concern about emergency planning zones. The agency, they said, must consider scientific principles, weather patterns and population when it sets such zones.

Under current NRC rules, communities near reactors must prepare evacuation plants for areas within 10 miles of the plants. The area can be adjusted during an accident.

But the panel said emergency plans should account for how each facility would react before a disaster strikes. The NRC also establishes a 50-mile radius as an area of concern in which food and water might be contaminated by radioactivity.

Anti-nuclear groups have been urging the NRC for years to expand emergency planning zones to 25 miles. The NRC has said it has a variety of methods for protecting the public from inhaling airborne radioactive material during an accident, including sheltering and evacuating people in phases and supplying potassium iodide pills.

The expert panel also called for NRC Chairman Gregory Jaczko to explain why he told Congress last year that the Fukushima plant's spent fuel pool at Unit 4 was destroyed and empty of water. He was wrong.

"In essence, he informed Congress that the Fukushima [plant] was about to become another Chernobyl and recommended an evacuation of 80 kilometers from the [nuclear power plant] site," the panel said.

"Fukushima was no Chernobyl," former NRC Chairman Dale Klein, the panel's co-chairman, told reporters at the National Press Club today.

NRC called for the evacuation of all U.S. citizens within 50 miles of the plant, which exceeded Japanese officials' call for a 12-mile evacuation zone. Jaczko later said that the recommendation came amid confusion and scarce information from Japan and that it was made based on the assessment of conditions at the site as they were understood at the time.

"The committee feels that the technical basis should be clarified to better understand the source of the uncertainties," the experts wrote.

The panel also called on the NRC to reconsider assumptions that underlie its regulatory framework and create a new analytical tool to review reactor designs to ensure they can withstand earthquakes, tsunamis and other natural disasters -- an issue the NRC hasn't addressed.

Klein said the United States has done a good job of looking at rare, high-consequence events, but the NRC and nuclear industry need to take a second look to ensure plants are safe from "low probability, high consequence" events.

The NRC should also work with other federal agencies to create a better emergency planning system, and should consider changing various hardware on plants to ensure greater reliability.

Michael Corradini, a panel co-chairman and a professor of nuclear engineering and engineering physics at the University of Wisconsin, said the design basis of the Fukushima plant to safeguard the facility against tsunamis was insufficient and the approach laid out in the report would have identified such weaknesses.

The panel also called for the wider circulation of scientific information about the disaster. Klein pointed out that despite dire reports from the media, no one has died from radioactive releases around the Fukushima plant.

Klein said NRC rules stemming from the Fukushima disaster should be subject to a cost-benefit analysis. The agency is formulating orders and rules to upgrade safety at U.S. reactors, but Jaczko has said he doesn't believe those provisions should be subject to cost-benefit analyses.