Climate change can affect every aspect of nuclear plant operations like fuel handling, power and steam generation, maintenance, safety systems and waste processing, the credit rating agency said.
However, the ultimate credit impact will depend upon the ability of plant operators to invest in mitigating measures to manage these risks, it added.
Close proximity to large water bodies increase the risk of damage to plant equipment that helps ensure safe operation, the agency said in a note.
Moody’s noted that about 37 gigawatts (GW) of U.S. nuclear capacity is expected to have elevated exposure to flood risk and 48 GW elevated exposure to combined rising heat and water stress caused by climate change.
Parts of the Midwest and southern Florida face the highest levels of heat stress, while the Rocky Mountain region and California face the greatest reduction in the availability of future water supply, it said.
Nuclear plants seeking to extend their operations by 20, or even 40 years, beyond their existing 40-year licenses face this climate hazard and may require capital investment adjustments, Moody’s said.
“Some of these investments will help prepare for the increasing severity and frequency of extreme weather events.”