A new report by the US Government Accountability Office (GAO) stresses the need to address the potential impacts of climate change during the licensing of NPPs. The GAO is an independent, nonpartisan agency that works for the US Congress and is responsible for investigating federal government expenditures, was asked to review the climate resilience of energy infrastructure. Its 73-page report, “Nuclear power plants: NRC should take actions to fully consider the potential effects of climate change”, looks at how climate change could affect NPPs and how this could affect the Nuclear Regulatory Commission’s (NRC’s) actions to address possible risks.
GAO gathered data between November 2022 to the present day. Sources included staff from the NRC, the Department of Energy, the Federal Energy Regulatory Commission, the National Oceanic and Atmospheric Administration, the Federal Emergency Management Agency and the US Forest Service. GAO staff also visited the Palo Verde NPP in Arizona and Turkey Point plant in Florida and interviewed employees. GAO used NRC data on the location of all 54 operating US NPPs, as well as 21 shut-down plants that have used nuclear fuel stored in fuel pools or in dry storage.
The report says commercial NPPs in the US were licensed and built on average 42 years ago, since when weather patterns and climate-related risks have changed. “Climate change is expected to exacerbate natural hazards – such as heat, drought, wildfires, flooding, hurricanes, sea level rise, and extreme cold weather events – that can affect nuclear power plant safety and operations in various ways. Some of these effects are already occurring, and many are expected to continue to worsen.”
However, NRC does not use climate projections data to identify and assess risk as part of the safety reviews it conducts or the probabilistic risk assessments it reviews during the initial licensing process.… NRC has the opportunity to consider climate risks more fully and, in doing so, to better fulfil its mission to protect public health and safety.”
GAO says the 75 operating and shutdown US NPPs “are located in areas where climate change is expected to exacerbate heat, drought, wildfires, or all three”. Heat and drought can affect the water used for cooling. “Specifically, higher than-usual ambient air temperatures may increase the temperature of water used for cooling. Drought can also reduce the supply of cooling water. If a plant has an insufficient supply of cooling water or its cooling water approaches or exceeds the maximum allowable temperature for cooling certain reactor components, a licensee may need to temporarily limit or stop operations to ensure plant safety.”
Higher temperatures in the bodies of water into which NPPs discharge cooling water may also require a plant to limit or temporarily stop operations to comply with laws designed to protect aquatic ecosystems and wildlife. In addition, high temperatures can also degrade the performance or cause failure of pumps and other equipment, reduce the lifetime of plant components, and reduce the overall efficiency of power plants. Warmer temperatures may also increase levels of certain algae or other biological material which can block cooling water systems and lead to reduced production or a temporary plant shutdown.
The report says that, while all operating and shutdown plants are located in areas where climate change is projected to increase measures of heat, the effects of climate change on maximum temperatures are projected to be most severe in the South, where one-third of the plants are located. “The plants in the South are projected to experience an annual average of from 21 to 31 days with higher maximum temperatures than historical high temperatures.” In addition, climate change is expected to increase drought intensity in some regions, specifically in the Southwest.
The report concludes that assessing whether NRC’s licensing and oversight processes adequately consider climate risks to NPPs and developing and implementing a plan to address any gaps identified would help the agency do so. “As NRC makes licensing, licence renewal, and oversight decisions, adopting an approach that incorporates the best available information on climate risks and ways that those risks may affect nuclear plants, would provide greater assurance that licensees have adequate measures to address risks from climate change.”
GAO makes three recommendations:
- The Chair of the NRC should direct NRC staff to assess whether its licensing and oversight processes adequately address the potential for increased risks to nuclear power plants from climate change.
- The Chair of the NRC should direct NRC staff to develop, finalise, and implement a plan to address any gaps identified in its assessment of existing processes.
- The Chair of the NRC should direct NRC staff to develop and finalise guidance on incorporating climate projections data into relevant processes, including what sources of climate projections data to use and when and how to use climate projections data.
Sources: Nuclear Regulatory Comission documents; summary of literature; GAO (icons) | GAO-24-106326
