A watchdog group released a report today criticizing the Nuclear Regulatory Commission for failing to quickly enough mandate key safety changes at U.S. nuclear power plants in the wake of Japan's nuclear disaster last year and industry for attempting to skirt new rules.

The Union of Concerned Scientists report faults the NRC for delaying changes to its regulatory structure to address severe accidents.

An internal NRC task force called on the commission last year to clarify the current "patchwork" of regulations for severe accidents. The expert panel was assembled to pull lessons from the March 11, 2011, earthquake and tsunami that crippled Japan's Fukushima Daiichi nuclear complex, triggering core meltdown in three reactors, hydrogen explosions and radioactive leaks.

The NRC decided to postpone action on the regulatory overhaul but move ahead with 11 other task force recommendations, including measures to boost instrumentation on spent fuel pools, ensure vents are reliable and protect reactors against power loss. Scott Burnell, a spokesman for the NRC, said the commissioners indicated in their initial response to the recommendations that regulatory change was such an involved effort that it would be put on the long-term track, and that some of the staff have been examining possible methods for re-evaluating the agency’s regulatory process.

The NRC's decision puts the "cart before the horse" and could undermine the agency's rulemaking going forward, said Dave Lochbaum, the author of the UCS report and director of the group's Nuclear Safety Project.

"Absent that foundation, the implementation of the 11 task force recommendations will likely only add more patches to the existing patchwork and widen the safety level gap between the reactors," Lochbaum wrote.

Burnell defended the commission’s response and said the agency is on the brink of issuing mandatory orders for plant modifications and enhancements, as well as requiring extensive reanalysis of existing plants to determine whether and where additional enhancements are warranted. “This is the result of the NRC staff’s devoted, determined effort, as well as significant senior management guidance,” he said.

The group also accused the nuclear power industry of prematurely buying safety equipment to meet NRC rules that haven't been finalized, and said the commission needs time to ensure the equipment protects the public.

The Nuclear Energy Institute said at a news briefing that plant operators are buying 300 pieces of equipment to protect reactors from any disaster. NEI said that the step is proactive and will meet tight deadlines, and that it protects reactors against a host of unknown dangers.

But Ed Lyman, a physicist with the group's Global Security Program and a co-author of the report, said the industry's purchase of backup equipment -- slated to cost about $100 million -- may "end up on the junk pile if it doesn't ultimately meet the requirements that the NRC has yet to develop."

Lyman said industry is trying to save money by building regional warehouses where operators can share equipment that may not meet federal standards. "The rationale for what the industry is doing is pretty clear," he said.

Burnell said the NRC has repeatedly said that industry’s approach to obtaining more equipment has to be formally evaluated by commission staff, and that closely examining issues related to the Fukushima event early will lead to more information and better solutions.

Lyman also took aim at the NRC's 10-mile emergency planning zones and said radioactive "hot spots" were detected 25 miles away from the Fukushima plant in Japan. The NRC is underestimating how difficult it would be to expand current planning zones and quickly evacuate large populations living near nuclear plants like Entergy Corp.'s Indian Point nuclear power complex north of New York City during emergencies, Lyman said.

"Although we were hopeful that the real-world example of what happened in Fukushima would send a message to the NRC to consider whether those 10-mile zones are still appropriate, it appears that they are not planning to move any time soon to revisit that," he said.

Lastly, Lyman said the NRC is "dragging its feet" on moving spent fuel from densely packed wet pools to dry cask storage.

The report did acknowledge that the NRC responded swiftly to the Japanese disaster and handled a flood of inquiries from government officials, the media and concerned citizens. The group also applauded NRC Chairman Gregory Jaczko's decision to evacuate U.S. citizens within 50 miles of the Fukushima plant, as well as the agency's decision to assemble a task force to pull lessons from the disaster.