The overnight assault caused a blaze at the facility, prompting fears over the safety of the plant and evoking painful memories in a country still scarred by the world’s worst nuclear accident, at Chernobyl in 1986. The site of that disaster is also under Russian control as of Feb. 24, 2022.
On March 4, Ukrainian authorities reported to the International Atomic Energy Agency that the fire at Zaporizhzhia had been extinguished and that Ukrainian employees were reportedly operating the plant under Russian orders. But safety concerns remain.
The Conversation asked Najmedin Meshkati, a professor and nuclear safety expert at the University of Southern California, to explain the risks of warfare taking place in and around nuclear power plants.
How safe was the Zaporizhzhia power plant before the Russian attack?
The facility at Zaporizhzhia is the largest nuclear plant in Europe, and one of the largest in the world. It has six pressurized water reactors, which use water to both sustain the fission reaction and cool the reactor. These differ from the reaktor bolshoy moshchnosty kanalny reactors at Chernobyl, which used graphite instead of water to sustain the fission reaction. RBMK reactors are not seen as very safe, and there are only eight remaining in use in the world, all in Russia.
The reactors at Zaporizhzhia are of moderately good design. And the plant has a decent safety record, with a good operating background.
Ukraine authorities tried to keep the war away from the site by asking Russia to observe a 30-kilometer safety buffer. But Russian troops surrounded the facility and then seized it.
What are the risks to a nuclear plant in a conflict zone?
Nuclear power plants are built for peacetime operations, not wars.
The worst thing that could happen is if a site is deliberately or accidentally shelled and the containment building – which houses the nuclear reactor – is hit. These containment buildings are not designed or built for deliberate shelling. They are built to withstand a minor internal explosion of, say, a pressurized water pipe. But they are not designed to withstand a huge explosion.
It is not known whether the Russian forces deliberately shelled the Zaporizhzhia plant. It may have been inadvertent, caused by a stray missile. But we do know they wanted to capture the plant.
If a shell hit the plant’s spent fuel pool – which contains the still-radioactive spent fuel – or if fire spread to the spent fuel pool, it could release radiation. This spent fuel pool isn’t in the containment building, and as such is more vulnerable.
As to the reactors in the containment building, it depends…