Title page

Contents

Highlights 2

Letter 6

Background 10

The Nuclear Power Industry and U.S. Plant Operations 10

NRC's Role 14

NRC's Regulatory Approach 15

Climate Change Is Expected to Exacerbate Natural Hazards That Pose Risks to Nuclear Power Plants 18

Heat, Drought, and Wildfires Pose Risks to Nuclear Power Plants, and Climate Change Is Expected to Exacerbate These Hazards, Particularly in the South and Southwest 19

Flooding, Hurricanes, and Sea Level Rise Pose Risks to Nuclear Plants, and Climate Change Is Expected to Exacerbate These Hazards, Particularly in Coastal Regions 23

Extreme Cold Weather Events Pose Risks to Nuclear Power Plants, and Climate Change May Affect These Events in Certain Regions 30

NRC's Actions to Address Risks to Nuclear Power Plants from Natural Hazards Do Not Fully Consider the Potential Effects of Climate Change 32

NRC's Oversight of Nuclear Power Plants Includes Actions to Address Risks from Natural Hazards 32

NRC's Actions Do Not Fully Consider the Potential Effects of Climate Change 39

Conclusions 44

Recommendations for Executive Action 45

Agency Comments and Our Evaluation 45

Appendix I: Objectives, Scope, and Methodology 47

Appendix II: Available Federal Data on Heat, Cold, Wildfires, Flooding, Storm Surge, and Sea Level Rise 54

Appendix III: Nuclear Power Plant Exposure to Selected Natural Hazards 59

Appendix IV: Comments from the Nuclear Regulatory Commission 70

Appendix V: GAO Contact and Staff Acknowledgments 72

Table 1. Potential Exposure to Current and Future Hazards at Operating Nuclear Power Plants 60

Table 2. Potential Exposure to Current and Future Hazards at Shutdown Nuclear Power Plants 67

Figure 1. Map of Operating and Shutdown Nuclear Power Plants by U.S. Census Region 11

Figure 2. Nuclear Power Plant Components and Operations for a Pressurized Water Reactor 13

Figure 3. Measures Consistent with the Nuclear Regulatory Commission's (NRC) Defense-in-Depth Approach 17

Figure 4. Examples of Natural Hazards that May Pose Risks to Nuclear Power Plants 18

Figure 5. Nuclear Power Plants Located in Areas with Exposure to No/Low, Moderate, and High/Very High Wildfire Hazard Potential 22

Figure 6. Nuclear Power Plants Located in Areas with High and Moderate Flood Hazard 25

Figure 7. Nuclear Power Plants Located in Areas with Exposure to Storm Surges from Category 4 and Category 5 Hurricanes 27

Figure 8. Nuclear Power Plants in the National Oceanic and Atmospheric Administration (NOAA) Coastal Regions and Projected Sea Level Rise in 2050 29

Figure 9. Timeline of Selected Nuclear Regulatory Commission (NRC) and Industry Actions after the Fukushima Dai-ichi Accident in 2011 35

Figure 10. Examples of the Diverse and Flexible Coping Strategies (FLEX) and Strategic Alliance for FLEX Emergency Response (SAFER) Center Equipment 39