Nuclear plants face more heat risk than they’re prepared to handle

Climate change—particularly intense heat—is advancing so rapidly that it poses physical as well as credit risks to America’s aging nuclear fleet, a new report from Moody’s Investors Service finds.

“Our plants are fairly hardened to severe weather,” said David Kamran, a projects and infrastructure analyst at Moody’s and the lead author of the report. “But climate change is moving quickly.”

America’s nuclear power plants produce roughly 20% of the country’s electricity and represent more than half of all of its carbon-free power generation. After the earthquake and tsunami that caused a meltdown at Japan’s Fukushima-Daiichi nuclear power plant in 2011, the US Nuclear Regulatory Commission asked domestic plants to conduct their own assessments of risks from climate change and other natural hazards. A 2019 Bloomberg review of correspondence between the commission and owners of 60 plants concerning those assessments found that 54 of their facilities weren’t designed to handle the flood risk they now face.