Waterford ― The federal Government Accountability Office warns that Millstone Power Station and other nuclear plants could face temporary shutdowns and damaged equipment in the future from flooding, rising sea levels, hurricanes and other natural hazards caused by climate change.

The nonpartisan office, which provides auditing, evaluation and investigative services to Congress, recently conducted a study of energy infrastructure, during which it “analyzed available federal data and reviewed regulations, agency documents, and relevant literature.”

The study also included interviews with officials from the Nuclear Regulatory Commission, U.S. Department of Energy, National Oceanic and Atmospheric Administration and experts from the nuclear industry, academia and non-government organizations.

On Tuesday, the office released a 74-page draft report of the study’s findings.

It recommended that the NRC, which maintains oversight of all 54 nuclear power plants in the United States, examine its licensing and oversight processes to make sure they sufficiently prepare plants for climate change-related hazards, including flooding.

According to the office report, the NRC said the recommendations prescribed by the office were “consistent with actions that are either underway or under development.”

NRC officials the office interviewed said the NRC’s current processes “provide an adequate margin of safety to address climate risks.” But the office found that the NRC had not conducted any assessment that showed that was the case.

The NRC has taken steps to ensure that power plants address risks caused by natural hazards after a 2011 tsunami at Japan’s Fukushima Dai-ichi plant knocked out the power grid and destroyed a cooling water system that led to reactor meltdowns and caused extensive damage and environmental contamination.

Those steps included requiring safety margins in reactor designs, measures to prevent radioactive releases and maintenance of backup equipment should a natural hazard event occur.

The office says the NRC currently only considers historical weather data in its processes. The report says the NRC should also consider climate change projections, in an effort to look to the future, not just the past.

“Most commercial nuclear plants in the United States were built in the 1960s and 1970s, and weather patterns and climate-related risks to these plants have changed since their construction,” the office report read.

U.S Rep. Joe Courney, D-2nd District, who toured Millstone last week with federal, state, local and Finnish officials, said during the tour “plant officials specifically described the infrastructure and design protections in place to address sea level rise.”

“It well surpasses levels experienced during Hurricane Sandy in 2012, which was literally the high-water mark weather event since the plant opened,” Courtney added.

Many power plants, including Millstone, which is located hundreds of feet from Long Island Sound, are positioned for natural flooding risks as they draw water directly from bodies of water to cool their reactors. According to the office report, flooding can cause water inundation, which can damage reactors’ cooling systems and fuel cycles.

Millstone experienced minor flooding from Hurricane Ida in 2021, after which the NRC deemed that plant operator Dominion Energy Nuclear Connecticut had been too late in activating storm protection protocols, according to an Associated Press news story.

Dominion did not protest that finding, saying that company officials had relied on an inaccurate weather forecast. The NRC did not issue any penalties, the AP reported.

Dominion officials could not be reached to comment Wednesday.

Waterford First Selectman Rob Brule said Wednesday he would not speak on behalf of Millstone in terms of measures they’ve taken to protect Millstone from natural disasters. He said the town has dealt with coastal flooding before and has an emergency management plan to protect residents threatened by flooding or other disasters.

“I don’t think there’s a community that takes it more seriously than us, because we do have Millstone,” Brule said.

d.drainville@theday.com