Ukraine Nuclear Plant Attack: What Is the Risk?


The battle over a Ukrainian nuclear plant is over. The danger remains.

This story is no longer being updated. For the latest on the situation at Ukraine’s nuclear plants, check out our 360 analysis.

Russian troops took control of Ukraine’s Zaporizhzhia nuclear power complex last week after a battle that caused a fire but did not lead to a meltdown or any apparent leaks. But the situation is still dangerous.

The complex is the largest nuclear power plant in Europe, featuring six reactors installed between 1984 and 1995. In peaceful times, it provides about half of all Ukraine’s nuclear power, and about 20 percent of all its electricity from any source.

The assault on Zaporizhzhia was as close as warfare has ever come to a nuclear facility, and it caused a fire in a training building on the site; Ukrainian officials said there is minor damage to one reactor that does not affect its safety. Though fears are widespread around the world regarding what some including the U.S. embassy in Kyiv are calling a “war crime,” at this point there is no indication that a nuclear catastrophe has occurred or is imminent.


Rafael Grossi, the director general of the International Atomic Energy Agency, on Sunday said he was “extremely concerned” about the Zaporizhzhia facility, amid reports from Ukraine that Russian forces are not letting Ukrainian plant staff take actions without Russian approval, and that the Russians have limited communications within and from the site.

What happened?

On March 3, Ukraine reported to the International Atomic Energy Agency that Russian forces had broken through barriers in the town of Enerhodar and were approaching the power plant a few kilometers away. “The battle is going on in the town of Enerhodar and on the road to the ZNPP (Zaporizhzhia Nuclear Power Plant) site,” the Ukrainian regulator wrote in their letter to the IAEA. Shelling at the power plant site was reported later on Thursday.

At a news conference on Friday, the IAEA director general placed blame on the Russian forces for the damage, saying a “projectile was coming from the Russian forces,” the Washington Post reported.

By Friday, Russian forces had taken control of the power plant — a move that suggested the attack on the city had been carried out with the aim of capturing the facility.

What is the primary concern? Are we entering Chernobyl or Fukushima territory?

Almost certainly not. The design of the Zaporizhzhia reactors is fundamentally different from those at Chernobyl, and is considered much safer and easier to control. Furthermore, the reactors are nestled inside thick containment structures that are capable of withstanding significant shocks. At Fukushima, the meltdowns occurred because a tsunami disabled the backup diesel generators after the reactors themselves automatically shut down.


The fighting at Zaporizhzhia has reportedly stopped. Only one of the reactors is currently operating, at 60 percent capacity. Things would have to get substantially worse to produce a scenario where the reactors themselves are at risk: Further fighting would have to blow holes in the containment structures, several different backup systems would have to be damaged or destroyed, and external sources of power would have to fail.

Are there other risks beyond reactor meltdowns?

Yes. Meltdowns and problems with the reactors themselves are the least likely issue to arise, said David Woods, an Ohio State University emeritus professor of integrated systems engineering and an expert on safety in highly complex systems like nuclear power plants. The more likely scenario — though still a low-risk event — relates to the spent nuclear fuel and other sources of radioactive waste stored on the site, some of which also needs cooling. If power is diverted from cooling that waste, or some other action is taken that creates risks to those non-reactor sources, it could result in a release of radioactive material. That could be dangerous to people on the site or downriver, but it would not cause the widespread fallout of a Chernobyl-like catastrophe.

Is the danger over?

No. But the more time passes since the initial incident, the smaller the major risks get. Woods said that properly cooled reactors rapidly lose their leftover heat after shutdown, meaning even with some later catastrophe the risk of meltdowns drops. And of course, if the actual shelling and shooting have stopped, the risk of acute emergencies falls dramatically.

Who’s running the plant now?

The State Nuclear Regulatory Inspectorate of Ukraine has said that the plant’s personnel continue to operate it, though they may not be allowed to undergo shift changes, raising concerns about fatigue. A statement from Energoatom, which operates the plants in Ukraine, said the workers are “physically and morally exhausted,” and called for an immediate shift change.

“Are competent people in charge?” Woods asked. “Because if they’re in charge, everything’s going to be OK.”

Has there been any radiation leak at the plant?

How is that monitored, and is there a way to verify that independently? The International Atomic Energy Agency reported that there was no change in radiation at the site, and that on-site radiation monitors are functioning properly. U.S. Energy Secretary Jennifer Granholm said her department’s Nuclear Incident Response Team is monitoring the situation, and it has not yet detected any elevated radiation levels.

Is this a sign that Russia is going after Ukraine’s power grid? What is Russia’s end game?

Whether the Russian capture of the ZNPP reflects a broader military strategy of controlling the nation’s nuclear power plants — and ultimately its power grid — remains unclear.

In a video on Friday, Zelenskiy claimed that Russians had intentionally attacked the site. “Right now, Russian tanks are shooting at the nuclear power blocks. These are tanks equipped with thermal cameras, meaning they know what they are shooting at,” he said. But the Russian Ministry of Defense denied culpability, calling it a “provocation staged by the Kyiv regime.”

The IAEA said that the damage to the plant was caused by the Russian forces, but experts were unsure how to interpret it. “Either Russian leaders ordered the attack, which would indicate a level of recklessness and brinkmanship that we had not anticipated, or Russian troops on the ground fired on the plant without orders — or even possibly in contravention of them,” wrote Jon Wolfsthal, a senior adviser at Global Zero and former National Security Council senior director, in a Washington Post commentary.

Wolfsthal pointed to one reason that Russia might want to control Ukraine’s nuclear plants. “Perhaps in Putin’s mind, he needed to seize Ukraine’s nuclear assets to back up his narrative that Ukraine was pursuing nuclear weapons,” he wrote. (IAEA inspections have shown no such nuclear weapons program existed in Ukraine).


Are electricity grids typical targets in war?

Controlling or damaging an enemy’s power grid has become a common tactic in modern warfare and Russia has been a key perpetrator. As Grid’s Tech Reporter Ben Powers recently wrote, Russia launched a cyber attack on Ukraine’s grid in 2015, and experts said the grid could be a prime target in this war.

“It is not unprecedented that energy infrastructure has been attacked. In fact, from 2014-2018 there were ten attacks by pro-Russian separatists and others on energy infrastructure in Ukraine alone,” Anu Narayanan and Jonathan Welburn, experts at RAND corporation wrote in an email to Grid.

By taking over Zaporizhzhia, Russia now has control of one-fifth of Ukraine’s electricity generation. Before the invasion, Ukraine was preparing to connect its grid to neighboring European nations by 2023. For now, though, the grid is isolated, meaning Ukraine cannot easily access new power sources.

However, so far it appears Russia has opted for conventional weapons instead of hackers to exert control over Ukraine’s power system.

Are other power plants in Ukraine at risk?

Ukraine has three other nuclear power plants that are currently operational, which are concentrated in the western half of the country. It remains to be seen if Russia will try to target these facilities as well.

  • Dave Levitan
    Dave Levitan

    Climate Reporter

    Dave Levitan is a climate reporter for Grid where he focuses on interconnected stories about climate and science, and politics shaping action around both.

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    Lili Pike

    China Reporter

    Lili Pike is a China reporter at Grid focused on climate change, technology and U.S.-China relations.