Zaporizhzhia Nuclear Power Plant
The Zaporizhzhia Nuclear Power Station in southeastern Ukraine is the largest nuclear power plant in Europe and among the 10 largest in the world.
It has been under Russian occupation since 2022.
It was built by the Soviet Union near the city of Enerhodar, on the southern shore of the Kakhovka Reservoir on the Dnieper river.
It is operated by Energoatom, who operate Ukraine's other three nuclear power stations.
Reactor design
It has six VVER-1000 reactors for a total power generation capacity of 6 GW.
The reactor complex consists of the reactor vessel, in which uranium-dioxide fuel rods are immersed in water and control rods are inserted at the top.
The water is both coolant and moderator.
A pressuriser holds the water at a high but constant pressure — around 150 atm — to prevent it from boiling. This is the primary cooling circuit.
As the water heats up, the heat is moved to a secondary cooling circuit, where it converts a separate volume of water into steam.
This steam is fed to turbines to generate electricity.
In this design, the water in the primary circuit does not leave the reactor vessel at any time.
In RBMK reactors like at Chernobyl, the coolant and the moderator are different (light water and nuclear graphite respectively) and the coolant — which is radioactive for having been exposed to the nuclear fuel — flows out of the reactor vessel.
Unlike Chernobyl, the VVER-1000 reactor and its power-generation units at Zaporizhzhia are placed inside a large airtight chamber called a containment.
Risks and threats
During the Russian invasion of Ukraine, the Zaporizhzhia Nuclear Power Plant has become the center of an ongoing nuclear safety crisis, described by Ukraine as an act of nuclear terrorism by Russia.
It has seen destruction of its infrastructure via shelling, damage to its power lines.
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