The Resilience and Safety of Nuclear Power in the Face of Extreme Events

Nuclear power has not only proven its resilience during the pandemic but has also shown that it is safe and well suited to meet changing energy needs. Since the pandemic began, the share of nuclear power has increased in some countries, including Brazil, India and South Korea. In the United Kingdom, for example, nuclear power has played a significant role in drastically reducing the amount of coal burning for electricity; the pandemic-induced lower demand for electricity allowed the UK to temporarily close coal plants in favour of an increased use of nuclear power. 

Climate change
Just as the resilience of a plant’s workforce has been necessary to continue operations unimpeded during the ongoing pandemic, their resilience and a nuclear power plant’s robust design are also required in the face of extreme weather events, including those driven by climate change.   

Caused by the global mean temperature increase, climate change is altering the severity and frequency of weather events, such as temperature extremes, periods of heavy rainfall, high winds and major sea level rises. These changes are expected to continue to increase in the near to long term. 

“While rising water and air temperatures may pose challenges to the continuity of reactor operation by limiting its cooling capacity, it’s the extreme floods and winds that may affect reactor safety by posing threats to the installation’s design,” said Rzentkowski. “One of the challenges with climate change is that, as it continues to progress and make conditions more extreme, past observations and predictive models become less reliable. We should thus start anticipating these events and periodically reassess the relevant risks to ensure that accident prevention and mitigation measures remain adequate.” 

Natural events
Nuclear power plants may also be affected by extreme natural events, such as earthquakes, tornados, volcanic activity, ice storms and flooding. In rare circumstances, these events can be extreme enough to exceed the design capacity of a nuclear power plant.

An example of this is the accident at the Fukushima Daiichi Nuclear Power Plant in Japan on 11 March 2011, which was triggered by a tsunami that followed a massive earthquake. While the nuclear power plant was damaged by these events and the consequent hydrogen explosions, no lives were lost due to the accident. 

In the aftermath of the Fukushima Daiichi accident, concrete steps have been taken to further enhance safety at existing nuclear power plants and refine the designs of new plants against extreme events. These measures include, for example, alternative cooling options, environmentally qualified back-up generators, shields and seals to guard against wind, and dykes and other embankments to protect sites against flooding. 

All types of external events that may affect a nuclear site or the safety of nuclear installations are also addressed by the IAEA safety standards, including site evaluation and design and safety assessment. These standards reflect the current state of practice and are used to ensure safety throughout a plant’s lifetime. The IAEA also provides guidance through its Nuclear Energy Series and other technical publications such as Adapting the Energy Sector to Climate Change.

Matthew Fisher is Communications Program Liaison at the Idaho National Laboratory (INL). This article is published courtesy of the International Atomic Energy Agency (IAEA).