Dive Brief:

• The U.S. Nuclear Regulatory Commission announced Thursday that it expects to publish a final rule this spring in the Federal Register, based on lessons learned from the 2011 disaster at Japan's Fukushima nuclear plant, aiming to mitigate the impacts of "severe events at U.S. reactors."
• The new rule would require plants to maintain resources and procedures to cool a reactor's core and spent fuel pool in the event normal emergency power is lost. It would apply to operating commercial nuclear power plants and power reactor license applicants.
• But critics say the regulators watered down the final rule, stripping out a provision that would have required plant owners to update their designs, structures, systems and components in order to protect against real-world hazards. The nuclear industry maintains plants are "well protected" and are designed to withstand extreme storms and earthquakes.

Dive Insight:

U.S. regulators have been considering new nuclear rules for more than five years now, attempting to build on the lessons-learned from Japan's 2011 disaster. Many plants in the United States were built decades ago, and the concern is whether they are prepared for storms which seem to have grown stronger in the ensuing years.

According to the Union of Concerned Scientists, the Republican-controlled NRC voted 3-2 on a stripped-down version of the rule that commission staff recommended in 2016. Staff's proposal recommended requiring plant owners to protect their facilities from the "real-world hazards they face today instead of 'design-basis' hazards that were estimated using now-obsolete information and methodologies when the plants were built decades ago," the group said.

UCS says regulators declined to require plant owners to strengthen their defenses against greater hazards.

"The rule that was approved today was originally intended to close that gap. The commission majority's action today removed that requirement and will simply maintain the uncertain — and inadequate — status quo," UCS said in a statement yesterday.

The commission and nuclear industry disagreed with the critique. NRC says the rule's "primary impact" comes in three areas:

• Nuclear operators will be required to maintain resources and procedures to cool a reactor's core and spent fuel pool, as well as preserve the reactor's containment, in the event a site loses all of its normal and emergency power sources;
• Plants will be required to maintain equipment that can reliably measure spent fuel pool water levels following a severe event;
• Reactors must also preserve the resources needed to protect the core, containment and spent fuel pool from external hazards.

The Nuclear Energy Institute (NEI), which represents the industry, said it supports the new rule and said regulators had affirmed that U.S. plants "are well protected."

"Plants were designed to withstand the most severe hurricanes, earthquakes and other natural hazards as assessed by experts. After their construction, more than $4 billion in additional equipment was added to protect against even more extreme events that were 'beyond design basis,'" NEI President and CEO Maria Korsnick said in a statement to Utility Dive.

In 2011, the Fukushima Daiichi plant experienced three meltdowns and the release of radioactive material, after an earthquake and subsequent tsunami knocked out the plant's emergency generators, needed to maintain safety. While there have been scant new nuclear projects built in the United States in recent years, existing plants are widely considered to be a key to keeping carbon emissions down.

According to NEI, U.S. nuclear plants have safety exceeded 90% capacity factors for 15 continuous years. The country has roughly 100 nuclear units to provide roughly 20% of the nation's electricity.