Ukraine’s nuclear power plants have been threatened as the Russian-Ukrainian war plays out. Nuclear power plants rely on external power to maintain various safety mechanisms. In the worst case scenario, a power outage will cause the leakage of radioactive substances. For Ukraine, the focus now may be on protecting plant cooling pools, reactors, and the power supply of the Chernobyl "sarcophagus."
The Chernobyl nuclear disaster in 1986 can be said to be one of the worst nuclear power disasters in history. An explosion occurred in the No. 4 unit of the power plant during an experiment, forcing responders to seal the No. 4 unit in a reinforced concrete protective dome called a "sarcophagus." The reactor was covered, allowing the other units to continue to operate until the power plant was officially shut down in 2000.
There is still a lot of nuclear waste in the Chernobyl power plant which requires continuous cooling. The Russian army occupied the Chernobyl nuclear power plant shortly after the invasion of Ukraine. The Verge reported that the spent fuel rod cooling pool will be the biggest "flaw" in Chernobyl.
▲ Sarcophagus completed in 2017（Source：Tim Porter, CC BY-SA 4.0, via Wikimedia Commons）
The nuclear power plant cooling system relies on external power supply and needs to be connected to the grid to operate. Therefore, once the power is cut off, the fuel may meltdown and release radioactive substances. Although there are many failsafe mechanisms, so this kind of failure will only occur in the worst case. In the long run, the current situation in Ukraine also raises concerns about nuclear power plants, as the non-stop conflict makes it difficult for workers to monitor radiation, communicate, and clean up.
Last week, the largest nuclear power plant in Europe, Zaporizhzhia nuclear power plant in Ukraine, was also attacked by Russian artillery shells and caught fire. Fortunately, according to a report from the International Atomic Energy Agency (IAEA), since the Chernobyl power plant has been closed, it will not cause a major safety impact. Some experts also pointed out that the fuel rods in the cooling pool have been in place for many years and can maintain effective heat dissipation without requiring electricity. In contrast, Zaporizhzhia nuclear power plant has not been powered off, it has been occupied by the Russian army for six days, and the situation is worrying.
On the 4th, the Zaporizhzhia nuclear power plant was attacked by Russian artillery fire. Fortunately, the fire was completely extinguished and the safety systems of the reactor were not damaged. However, this is the first time that a nuclear power plant in operation has been attacked. As IAEA Director-General Rafael Mariano Grossi stated, the situation was very dangerous, and both artillery shells and out-of-control fires have the potential to knock out nuclear power plants.
The "sarcophagus" of the Chernobyl nuclear power plant also cannot be ignored. This $1.7 billion sarcophagus can block 200 metric tons of radioactive material. Claire Corkhill, Chair of Nuclear Material Degradation at the University of Sheffield in the United Kingdom, stated that the ventilation system in the sarcophagus can be used to keep the reactor and old sarcophagus from continuing to corrode but requires electricity to function.
Ukrenergo, the operator of Ukraine's national grid, called on the Russian army to stop the conflict near the Chernobyl power plant in order to continue to repair the transmission line and restore the power grid. The original diesel generator in the Chernobyl power plant can only be used for 48 hours, and that time is now over.
（Image：Mond, CC BY-SA 3.0, via Wikimedia Commons）
