Plachkov explained that Zaporizhzhia is almost twice the size, though direct comparisons are difficult because the two facilities are completely different beasts.
Chernobyl used what's called RBMK reactors, or high-powered channel reactors, an older Soviet technology that was modified after the disaster and still operates in Russia today despite safety concerns.
Hamish de Bretton-Gordon, who led the chemical, biological, radiological and nuclear defence forces known as CBRN, said Zaporizhzhia's modern reactors should be reinforced to deal with huge forces such as a plane crashing into them.
This is a war zone, there are some munitions that are more deadly than an airplane hitting them, he said. Fighting from a nuclear power station is a good idea, but it's not a good idea. The situation is safe for now, according to the U.N. atomic watchdog. But IAEA Director General Rafael Mariano Grossi told the UN Security Council on Thursday that this could change at any moment. It's not just the reactors.
The area around the plant has silos of nuclear waste, and the surrounding soil could release radiation if disturbed, de Bretton-Gordon said.
If this does not catch fire or blow up, the contamination is unlikely to be isolated to Ukraine, he said. It is likely to have an impact on Europe and Russia as well. If a big accident happens, it could have serious consequences for people in the Ukrainian Black Sea port of Odesa, as well as people in Romania, Bulgaria, Turkey and Russia, said Juan Matthews, a visiting professor at the Dalton Nuclear Institute at Britain's University of Manchester.
He said that the reactors of the plant are on the banks of the Dnieper and if radioactive material were to escape into the river, it would not be a good situation for the Black Sea, which is a dead end or a cul-de-sac. It's possible that the fishing industry could be killed for the whole of the Black Sea, which could be disastrous for countries around there. In the event of a meltdown or a cracked reactor containment unit, you would get all kinds of radioactive materials in the form of dust and things that would go into the air and you would have a similar situation to the Chernobyl accident, according to Matthews.
What can I do?
The U.N. has backed calls from Ukraine, the U.S. and other Western governments for a demilitarized zone around the plant.
That would involve Russia handing back the plant to Ukraine or a force of U.N. peacekeepers who patrol and maintain other demilitarized zones around the world.
Grossi told the Security Council that the IAEA has pleaded for access to let its inspectors assess the damage, check the safety systems and take urgent safeguards activities to ensure that nuclear material is only used for peaceful purposes.
Moscow has shown no signs that it's willing to vacate the plant, which would effectively be ceding a major prize in its war, just as Ukraine seems to be mounting a stiff counteroffensive.
Russia's Security Council met at the UN on Thursday. Ambassador Vassily Nebenzia said the world was being pushed to the brink of nuclear catastrophe, comparable in scale with Chernobyl. He said that IAEA officials could visit the site as soon as this month.
In a war that has seen Moscow bomb houses, hospitals and other civilian sites – just as it did in Syria and Chechnya – its opponents see its tactics around Zaporizhzhia as another cynical and dangerous ploy.
Ukraine's president Volodymyr Zelenskyy said on Thursday night that no one else has used a nuclear plant so clearly to threaten the whole world. The world should immediately act to expel the occupiers from the territory of the Zaporizhzhia nuclear power plant.