Ukraine invasion: Will Russia’s attack on the Zaporizhzhia nuclear plant cause a meltdown?

Shelling at the Zaporizhzhia nuclear power plant has injured two people and caused a fire, but it is unlikely to release radiation unless the situation gets significantly worse

Physics



4 March 2022

By Matthew Sparkes

Europe’s largest nuclear power plant, located in south-eastern Ukraine, has been shelled by Russian forces overnight, causing concern about the potential release of radioactive material.

Ukraine’s nuclear regulatory authority said that a fire had broken out at the Zaporizhzhia nuclear power plant but it didn’t affect “essential” equipment. The group also reported no change in radiation levels at the plant, suggesting that none of the uranium-235 fuel has been released.

A projectile hit a training building in the vicinity of one of the plant’s reactor units, causing a fire. Ukrainian regulators say safety systems weren’t affected, but warned that the situation meant they hadn’t been able to check the entire site – firefighters were initially unable to tackle the blaze because they were being shot at, said a plant spokesperson. Five of the six reactors are now turned off, with one still operating safely. Two people were reported injured.

What are the risks?

Ukraine’s foreign minister Dmytro Kuleba tweeted a warning that if an explosion occurs it could be “10 times larger than Chernobyl”, while President Volodymyr Zelenskyy reportedly said in a speech overnight that “if there is an explosion that’s the end for everyone. The end for Europe. The evacuation of Europe.”

Is that right?

Experts have dismissed the suggestion that an explosion was imminent, or even likely. Mark Wenman at Imperial College London said in a statement to the UK Science Media Centre that he believes the plant is well protected, so the chance of radiation leaks is minimal.

“The essential reactor components are housed inside a heavily steel reinforced concrete containment building that can withstand extreme external events, both natural and man-made, such as an aircraft crash or explosions,” he said. “The reactor core is itself further housed in a sealed steel pressure vessel with 20-centimetre-thick walls. The design is a lot different to the Chernobyl reactor, which did not have a containment building, and hence there is no real risk, in my opinion, at the plant now the reactors have been safely shut down.”

So is everything safe?

There are still risks. James Acton, co-director of the Nuclear Policy Program at the Carnegie Endowment for International Peace in Washington DC, pointed out that these reactors will now be reliant on external power for cooling and that if power is cut off and the ability to cool the reactors is lost, there is a chance of a meltdown – exactly what happened at Japan’s Fukushima nuclear plant in 2011. This is why it is vital that fighting in the area is stopped and staff are allowed in to safely manage the plant.

The State Nuclear Regulatory Inspectorate of Ukraine said in a statement that losing cooling “will lead to significant radioactive releases into the environment” that could be worse than Chernobyl.

What is likely to happen next?

The director-general of the International Atomic Energy Agency (IAEA), Rafael Mariano Grossi, has called for a halt in fighting and warned of severe danger if any reactors were hit. The UK’s Nuclear Industry Association backed his calls for a Russian ceasefire.

The IAEA is putting its Incident and Emergency Centre (IEC) on full alert. This is a quick-reaction team that is designed to respond to nuclear incidents, whether accidental or due to deliberate acts.

Has a nuclear power plant ever been attacked before?

The Zaporizhzhia plant itself was reportedly the target of an attempted attack in 2014 when 40 people claiming to be members of the far-right group Right Sector tried to gain access but were stopped by guards.

Despite nuclear power plants being an obvious target for terrorists, there has never been a successful attack on one, and they have never been targeted during war – perhaps because the repercussions of it would probably be global and also affect whatever state launched the attack. The World Nuclear Association says that, even in the tense days of the cold war, nuclear power plants weren’t typically thought of as targets.

Greenpeace once crashed a drone into a nuclear power plant and claimed that it showed their vulnerability to terrorist attack, but in reality, it would require a vast explosion to release nuclear material.

Has Russia broken international law?

Tom Scott at the University of Bristol, UK, said in a statement to the UK Science Media Centre that he believes Russia has broken international law. “Shelling nuclear power plants is against the Geneva Convention and this is obviously very worrying,” he says. “It would be more concerning if the reactors were being deliberately targeted to induce a nuclear incident.”

The shelling has certainly ratcheted up an already extremely tense situation. Nikolai Steinberg, a former chief engineer at Chernobyl, said that the attack displayed an “immoral and barbaric attitude towards humanity as a whole and each human life individually”.

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