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In Ukraine, a surge in military hostilities has again thrown the safety of the country’s operational nuclear plants into jeopardy. Russia has been targeting conventional Ukrainian power stations, the transmission grid, and substations with the heaviest barrages in months—likely a reaction to the Biden administration’s recent authorization that allowed Ukraine to fire long-range U.S. missiles into Russia and subsequent green light to receive and deploy U.S.-made anti-personnel mines. The Russian drone and missile strikes on the Ukrainian energy system have now put the three nuclear stations that depend upon them—in Khmelnytskyi, Rivne, and South Ukraine—in grave danger.
“Russia’s attacks on the power grid and Ukrainian conventional power plants is negatively affecting the safety of Ukraine’s nuclear fleet,” Per Strand, director general of the Norwegian Radiation and Nuclear Safety Authority, said. (Norway works closely with Ukrainian regulators to maintain reactor safety.) “Russia is not targeting the nuclear plants themselves but rather damaging the electric system as a whole. This causes the power in the transmission grid to fluctuate, which undermines the reactors’ security.”
In Ukraine, a surge in military hostilities has again thrown the safety of the country’s operational nuclear plants into jeopardy. Russia has been targeting conventional Ukrainian power stations, the transmission grid, and substations with the heaviest barrages in months—likely a reaction to the Biden administration’s recent authorization that allowed Ukraine to fire long-range U.S. missiles into Russia and subsequent green light to receive and deploy U.S.-made anti-personnel mines. The Russian drone and missile strikes on the Ukrainian energy system have now put the three nuclear stations that depend upon them—in Khmelnytskyi, Rivne, and South Ukraine—in grave danger.
“Russia’s attacks on the power grid and Ukrainian conventional power plants is negatively affecting the safety of Ukraine’s nuclear fleet,” Per Strand, director general of the Norwegian Radiation and Nuclear Safety Authority, said. (Norway works closely with Ukrainian regulators to maintain reactor safety.) “Russia is not targeting the nuclear plants themselves but rather damaging the electric system as a whole. This causes the power in the transmission grid to fluctuate, which undermines the reactors’ security.”
“It is clear that Russia is using the threat of a nuclear disaster as a major military lever to defeat Ukraine,” Shaun Burnie, a nuclear specialist at Greenpeace, told the Guardian. “But by undertaking the attacks, Russia is risking a nuclear catastrophe in Europe, which is comparable to Fukushima in 2011, Chernobyl in 1986, or even worse.”
Nuclear power plants rely on the electric grid to transmit the electricity they produce, as well as to receive power for reactor cooling and safety systems. Strand said that Ukraine’s plant operators “most probably” have the situation under control at the moment.
The Russian strikes marked the war’s 1,000th day on Nov. 19, with Russia attempting, as it has in past winters, to incapacitate as much of Ukraine’s power supply as possible—to hobble Ukraine and force its civilian population to suffer the cold weather. Putin’s goal “is to create a humanitarian catastrophe,” said Maxim Bevz, a Kyiv-based energy expert, who explained he is living without heat or electricity. “Kyiv has blackouts now for several days. Next week is supposed to be even colder.” The purpose, he said, is to break Ukraine’s morale and force as many people as possible to leave the country.
Poland and the Czech Republic are preparing for new influxes of winter refugees. The International Rescue Committee is working in Ukraine to provide financial assistance to help people purchase blankets, coats, heaters, and fuel for stoves. It noted that approximately 3.4 million people in Ukraine are internally displaced, and many living in collective shelters without adequate winter protection.
Despite the damage to its energy infrastructure since Russia’s invasion began in 2022, Ukraine entered this year’s cold season with energy sources—nuclear, coal, hydroelectric, and gas— just adequate to survive until spring, as long as its defenses protect all of those energy sources, said DTEK, Ukraine’s largest utility. Around two-thirds of its substations have been secured with physical reinforcements that protect against drones or shrapnel.
“If we get hit, as I assume we will, our goal is that Ukraine not fall into total darkness but to get things up and running again as fast as possible,” said Maxim Timshenko, DTEK’s CEO. About two-thirds of Ukraine’s supply hails from the reactors at the three nuclear plants, which does not include Zaporizhzhia in southeastern Ukraine, which is under Russian occupation. The burden on the operational sites is all the greater without Zaporizhzhia and the impairment of 90 percent of Ukraine’s thermal plants and 40 percent of its hydroelectric plants since 2022.
On Nov. 17, all but two of Ukraine’s operational nuclear power plants reduced electricity production by 10-60 percent as a precaution following Russian bombardment. The Russian strikes knocked out the main power lines for four substations, Ukrainian regulators told the International Atomic Energy Agency (Multiple substations supply one nuclear plant.) Only two of the country’s nine operational reactors currently generate electricity at full capacity.
“The less normal the electricity production is and the more that reactors must be throttled back or shut down, the greater the burden is on those reactors that remain online. This makes the grid all the more unstable and dangerous,” Strand said. Last winter, Ukraine lost 50 percent of its power capacity and thousands of miles of electric, gas, and heat networks.
The threat of a meltdown, experts say, stems from the stoppage of external electricity to the plants, which rely on it for their cooling systems. Nuclear plants must employ constant cooling to remove heat from the nuclear reactor core and transfer it to electrical generators or into the atmosphere. This makes them reliant on off-site power generation. If a substation that relays power to the reactor malfunctions, the plants have generators and batteries that kick in. The backup generation can cover outages for seven to 10 days. In 2022 and 2023, the Zaporizhzhia plant, Ukraine’s largest, suffered the complete loss of off-site power eight times.
Experts, such as Mycle Schneider of the World Nuclear Industry Status Report, say that back-up diesel generators are notoriously unreliable and prone to malfunction. “If you get a station blackout and the diesels do not start up, you meltdown starts within one hour,” Schneider said.
The sixth and final reactor at Zaporizhzhia, Europe’s largest nuclear station, was put into cold shutdown (nuclear fission stops) in April. The plant, which has been under Russian military control since March 2022, stopped generating electricity in September 2022 but had maintained one unit that provided heating for a nearby town. Greenpeace International said that although the six Zaporizhzhia reactors “remain on a cliff edge in terms of safety, they are at least in cold shutdown.” Since nuclear material remains in all six reactors and is still cooling, even with the complete loss of electrical power, a meltdown would not happen in just hours or days but would probably take several weeks.
“A situation as precarious as that in Ukraine right now has never happened anywhere else on this scale, even in peace time,” Strand said. “And now it’s happening in the middle of a war.”
“In an active war, no one can guarantee the safety of a nuclear power plant,” Schneider to the German media last year. “It is based on a system of complex regulations, inspections, maintenance, regular checks, and healthy, rested personnel. There is no basis for the safe operation of nuclear power plants in a war situation.”
Ukrainian authorities, Strand said, are well aware of the imminent danger and are scrambling to ensure safety and the regular flow of electricity. The obvious alternative—to shut them all down at once—is simply not an option as temperatures plummet across the country.