Enlarge image
Zaporizhia nuclear power plant: According to the operator, the last block was taken off the grid
Photo: Dmytro Smolyenko / NurPhoto / IMAGO
The last reactor still in operation at the Zaporizhia nuclear power plant in Ukraine, which is occupied by Russian troops, has been shut down.
This was announced by the Ukrainian state operator Energoatom in the messenger service Telegram.
The reason for the emergency shutdown of Block 6 is a fire triggered by attacks that damaged a high-voltage line between the power plant and the Ukrainian power grid.
There is currently a risk of violating radiation and fire protection, it said.
Energoatom announced on Monday morning that Block 6 supplies the nuclear power plant itself with electricity.
Europe's largest nuclear power plant consists of a total of six independent reactor blocks.
According to the International Atomic Energy Agency (IAEA), the last remaining main power line between the power plant and the Ukrainian power grid was only cut on Saturday – also after being shelled.
There is no longer a connection to the Ukrainian power grid.
The connection to the power grid was therefore maintained via a reserve line.
Multiple backup
In nuclear power plants, the power supply is crucial for cooling the fuel rods.
The decay heat from the nuclear fission process usually lasts for a few months after the shutdown, explained Wolfgang Raskob, group leader for nuclear safety at the Karlsruhe Institute of Technology, in late August in SPIEGEL.
If the power supply fails, there is a risk of a meltdown.
To prevent this, nuclear power plants are secured several times.
The plant in Zaporizhschja is also normally connected to two power grids, explained the technology historian Anna Veronika Wendland, who knows the nuclear power plant well, in SPIEGEL.
"Once on the state grid, into which it feeds itself, and on a reserve grid." If both fail, the nuclear power plant is supplied with electricity via diesel generators.
If they also fail and a core meltdown actually occurs, further protective measures are taken to prevent large quantities of radioactive radiation from escaping.
"Normally, the molten core would flow into the large concrete basement of the building, radioactivity would then hardly escape to the outside," Clemens Walther, professor at the University of Hanover and executive director of the Institute for Radioecology and Radiation Protection there, told SPIEGEL in mid-August (more on this read here ).
Nevertheless, it is important to avoid this emergency at all costs.
A week and a half ago, on August 25, there was also an emergency shutdown of the two reactors that were in operation at the time, followed by a power failure in the occupied southern Ukrainian regions.
The nuclear power plant was captured shortly after the start of the Russian invasion of Ukraine in early March.
Two experts from the IAEA are currently still in the power plant to monitor the security situation.
Artillery fire on the power plant site, which had been increasing for weeks, had increased international fears of a nuclear catastrophe.
Moscow and Kyiv accuse each other of shelling the power plant site and the surrounding area.
ani/AFP/dpa