Last month, we reported on the widespread deficiencies found in the procedures and equipment the country's 104 commercial nuclear reactors are supposed to rely on in the event of a catastrophe like the one that hit the Fukushima-Daiichi power plant in Japan.

This week, a special task force of Nuclear Regulatory Commission experts proposed to do something about those problems and other safety issues raised by the Fukushima disaster, where the fuel in three reactors melted down and an unknown amount of radioactive materials escaped into the surroundings.

The NRC's Japan Task Force said that U.S. nuclear plants are safe but called for potentially sweeping and costly changes to protect against catastrophic events like earthquakes and long-term blackouts.

The panel's 83-page report calls for upgrades at many plants and broad revisions to what it called a "patchwork" of NRC regulations governing catastrophic events that need to be streamlined.

Groups ranging from nuclear industry representatives to nuclear power critics and regulators cautioned that the NRC report is only the first step in what will almost certainly be a long process of adopting lessons from the Fukushima disaster, where three reactors partially melted down.

"We have a lot of work in front of us," said Tony Pietrangelo, chief nuclear officer for the nuclear industry's trade group, the Nuclear Energy Institute. The watchdog group Union of Concerned Scientists also on Wednesday released its own set of safety recommendations in light of Fukushima's experience.

"If a U.S reactor were faced with a similar challenge, maybe not the exact combo of earthquake and tsunami, but some other natural disaster or human error, it's unlikely that the story would have a happier ending," David Lochbaum, a nuclear engineer who works with the group, said in a statement.

ProPublica has been tracking nuclear safety issues since the March disaster, including the risk posed by spent fuel pools and the results of NRC inspections that found flaws of varying severity with emergency equipment and disaster procedures at all but five of the 65 U.S. reactor sites.

The NRC Task Force, launched in April, is scheduled to present its report to the five-member commission on July 19. Among the 12 main recommendations:

The Task Force also called for a broad reworking of NRC regulations governing preparation and response for major disasters that can cause damage exceeding the design limitations of a plant.

The current system reflects NRC's piecemeal reaction to disasters, such as the partial meltdown at Three Mile Island and the threat of a 9/11-style terror attack, over several decades, the report said. It should be replaced, the task force said, with a streamlined and "coherent regulatory framework."

Release of the report Wednesday touched off immediate debate about whether new rules would mean costly upgrades for nuclear companies and only a marginal safety benefit.

"Done poorly, they could significantly increase costs in the current operating fleet without improving safety one iota," Margaret Harding, an industry consultant, told Reuters. "Done well, and they will get at the real issues, eliminate the vagueness in the regulation, and improve safety."

Pietrangelo, of the Nuclear Energy Institute, said the companies expect there will be costs involved but that it was "way too early to speculate." He said nuclear companies already are mining the lessons from Fukushima and working on plans to extend their plants' ability to operate during a blackout.

Ed Lyman, an expert with the Union of Concerned Scientists, called the Task Force's recommendations "a good first step" but said the real test would be whether the commission follows them. "The devil is in the details," he said. "We are taking a wait and see approach."

Among other things, the UCS recommended that NRC extend the scope of its regulations to cover extreme, low-probability events; strengthen emergency planning; require plants to transfer spent fuel from storage pools to dry casks after five years; and bring all plants into compliance with fire rules.