Every nuclear reactor is a balancing act, where fuel rods are carefully held just close enough together to generate the heat needed to generate electricity, while being continuously monitored to prevent overheating, which would melt the fuel. This requires continuous cooling and highly trained personnel. The reactors themselves are covered with a steel shell and a heavy layer of concrete, expressly designed to withstand projectiles and plane crashes, and intended to contain the heat of melting fuel during a disaster. . The Chernobyl reactors did not have this level of protection, which led to the release of radioactive material into the open air.
Ukraine has four operational nuclear facilities, including Zaporizhzhia, according to the IAEA’s Power Reactor Information System database. According to Joshua Pollack of the Middlebury Institute of International Studies in Monterey, there are at least two worrying scenarios that experts are concerned about when nuclear power plants are gobbled up in war zones:
• While the reactors are very tough, their pools, containing used but still hot fuel rods, are not. If a cooling pond is damaged and stops working, the water will eventually boil and those fuel rods will catch fire, spitting radioactive particles skyward. This was a major concern during the Fukushima disaster.
• If a reactor shuts down, loses access to external power, and then loses emergency power, the coolant inside the reactor itself stops circulating. A short time later, the fuel caught fire inside the reactor and released hydrogen gas. “As we learned in Fukushima, it’s quite dangerous,” Pollack said. During this disaster, hydrogen explosions blew the roofs of the reactor buildings. This led to radioactive gas releases and mass evacuations.
There appear to be at least three explanations for Russian forces attacking Zaporizhzhia right now in their week-long invasion of Ukraine, said Melissa Hanham, an open source intelligence specialist affiliated with the Center for International Security and Cooperation in Stanford University. The first is simply in the fog of war, the invading Russian force takes control of all the facilities in its path, which led to the shooting at the factory. The second is a deliberate attempt to control a high-risk site, similar to the takeover of Chernobyl at the start of the invasion. The IAEA complained that Chernobyl personnel were not relieved to monitor operations there. A third explanation suggested by Ukrainian officials is that Russia intends to control and cut the country’s electricity as part of its invasion plan.
“If it’s under Russian control, you would ask for some confidence building by allowing the IAEA to have access and regular communication with whoever is running it, presumably Ukrainian personnel,” Hanham said.