The problem these days with temperatures is putting the management of nuclear power plants at risk. From its humble beginnings as a glacial rivulet in the Swiss Alps, the Rhone River rapidly transforms into one of the most industrialized waterways in the world. As it winds its way through southern France to the Mediterranean Sea, its cold water is drawn into boilers, drawn through pipes as a coolant, diverted for agriculture.
Its major customers include a nuclear reactor battalion. Since the 1970s, the river and its tributaries have helped generate about a quarter of France’s atomic energy. But this has not been the case in recent weeks. Amid a slow-burning heatwave that killed hundreds of people and triggered intense fires across Western Europe, and combined with water levels already low due to drought, the water in the Rhone has become too much hot for work.
It is no longer possible to cool the reactors without expelling water downstream so hot that aquatic life is extinguished. Thus, a few weeks ago, Électricité de France (EDF) started shutting down some reactors along the Rhone and a second large river to the south, the Garonne. This is now a familiar story: similar arrests due to drought and heat occurred in 2018 and 2019.
The cuts this summer, combined with malfunctions and maintenance on other nuclear power plants, have helped reduce France’s nuclear power generation by nearly 50%. Of all the low-carbon energy sources likely to be needed to combat climate change, nuclear power is generally considered to be the least perturbable.
It is the reinforcement that is called when the weather does not cooperate with other zero-carbon energy sources, such as wind and solar. But the nuclear industry faces its own climate risks. Problems with too much or too little water are most commonly associated with hydroelectric dams, which have struggled to keep production in dry places like the American West.
But as Swedish historian Per Högselius puts it, much of nuclear engineering today is not about splitting atoms, but about dealing with large-scale aquatic problems. Nuclear technicians are known to refer to their craft as a a very complicated way of boiling water, producing steam that makes the turbines spin. But much more is usually needed to keep nuclear power plant rectors cold.
That is why so many structures are located by the sea and along great rivers such as the Rhone. Many other industries are affected by warmer rivers, including large factories and power plants that run on coal and gas. But nuclear power plants are unique due to their immense size and the central role they play in keeping energy grids online in places like France.
And warming and dwindling rivers aren’t the only climate challenges they face. On the coasts, a combination of sea level rise and more frequent and intense storms carries an increased risk of flooding. Scientists also pointed to other more unusual challenges, such as more frequent algae blooms and exploding jellyfish populations, which they can clog the water pipes.
Nuclear power plants: temperatures at risk, but were they predictable?
Nuclear power plants are also built to last long into the future, with a lifespan extending for half a century or more. Many were built in the 1970s and 1980s, long before regulators thought they would take into account the climate-related threats they would eventually encounter, explains Natalie Kopytko, a researcher at the University of Leeds who has been digging into regulatory frameworks. to seek climate considerations.
“I have seen absolutely nothing about climate change, which was pretty scary”, He says. Where Kopytko saw climate invoked, plans assumed that current weather models would hold up well in the future. Some of the current concerns about climate change are related to safety and the industry has started making some moves to address them.
After the Fukushima disaster in Japan, caused by the 2011 Tohoku earthquake and tsunami, the United States Nuclear Regulatory Commission (NRC) began drafting new rules to strengthen existing plants to climate threats, such as storms and rising temperatures. sea level. The trial identified dozens of structures that could deal with flood problems under extreme conditions.
But in 2019 those plans were largely thwarted by the Republican-led leadership, which argued that the costs were too high to be adopted by the nuclear industry for such unlikely events. “This decision makes no sense”Democrat-appointed commissioner Jeff Baran wrote in dissent at the time.
The nuclear industry and environmental groups continue to disagree that existing regulations capture the latest scientific findings, particularly on the subject of sea level rise.
“There is a lot of scope on the safety side for nuclear power plants”says Doug True, chief nuclear officer of the Nuclear Energy Institute, a U.S.-based industrial group, adding that utilities regularly update their climate risk models and have already taken extensive measures to protect their facilities from weather conditions. extreme.
But these climate threats are once again discussed more openly, regulators in Europe and the United States are considering extending the life of nuclear power plants to combat climate change. In 2019, the NRC began approving 20-year extensions to some reactors, starting with the Turkey Point power plant in South Florida.
Environmental groups have presented interventions to stop the plan, arguing that a combination of more intense and hurricanes sea level rise it would have threatened the low plant in ways that regulators had not adequately considered. In February, the NRC revoked the extension for Turkey Point and other facilities pending a broader environmental review.
So far, most of the production cuts are due to water warming, not just in the Rhone and Garonne, but in places like the Tennessee River in the United States and coastal seas where far more plants are found. In recent years, nuclear power plants across Northern Europe have been forced to shut down or cut production because seawater has become too hot to safely cool the reactor cores.
Over the past decade, Connecticut’s Millstone Power Plant has experienced a series of shutdowns on hot summer days until regulators raised its cooling water temperature limit to -15 degrees Celsius.
Given the relative rarity of intense heat waves and outages due to storms, climate-related hiccups have little impact on overall energy production, accounting for less than 1% on average annual EDF production, for example. But the impact is increasing as temperatures continue to rise.
In an analysis published in Nature Energy last summer, a Stanford researcher found that there had been eight times more outages due to heat in the 2010s than in the 1990s. In a 2011 study on the impact of warming on the cooling systems of nuclear power plants, EDF scientists predicted a 3 ° Celsius increase in the temperature of the Rhone by 2050, indicating a greater potential for shutdowns during heat waves. .
And these disruptions can occur at critical times, such as summer heatwaves when energy demand is high. In France, where nuclear power normally provides 80 percent of the country’s needs, the current closures are coming at a particularly bad time, as Europe is in a hurry to support energy reserves due to the shortage of gas and oil due to the war in Ukraine.
Adapting your existing fleet can be difficult, says Thibault Laconde, CEO of Callendar, a Paris-based startup that advises companies on climate risks. It is not possible to move an already built structure and the overhaul of the systems is expensive.
It may be possible to redesign the pipes to achieve deeper and colder water, or to add new heat exchange systems that reduce the need for water, as many French factories did after the record 2003 heatwave in the country. But the costs are generally high and the efficiency gains small, says Laconde.
Building from scratch is easier. “The key question is when we start building new plants, how can we take into account the impact of climate change over the entire lifespan of the plant until 2080 or 2100”Laconde states, noting that the new generation of French reactorsrecently announced by President Emmanuel Macron, are mostly built from the coasts.
He adds that nuclear power works well in warmer climates, like Spain or the United Arab Emirates, because those plants were built to withstand them. “I think it’s possible to adapt,” says Laconde. In the United States, the only nuclear power plant in the desert, the Palo Verde plant in Arizona, relies on municipal wastewater rather than rivers or seas, although the plant has struggled with rising costs as more industries they compete for limited supplies.
NEI’s Doug True puts more inventory into a proposed new generation of smaller nuclear reactors, some of which use molten salts or air-cooled and are less dependent on the availability of water sources.
Meanwhile, regulators in France are expecting a long summer. While the heat can pass, the low water levels can persist, resulting in cuts that last for weeks or months. EDF recently told reporters that it expects further cuts in the coming months since water levels continue to dropleaving the country hoping for relief from the cold and harsh rains.
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