Every nuclear reactor is a balancing act, where fuel rods are placed close enough to generate the heat needed to generate electricity, constantly monitored to prevent overheating, which would melt the fuel. It requires continuous cooling and highly trained personnel. The reactors themselves are encased in a steel shell and a heavy layer of concrete, apparently designed to withstand projectiles and plane crashes, and to contain the heat of melting fuel in a disaster. The Chernobyl reactors lacked this level of protection, which led to an open air release of radioactive material.
Ukraine has four operational nuclear facilities, including Zaporizhia, according to the IAEA’s Power Reactor Information System database. According to Joshua Pollock of the Middlebury Institute of International Studies in Monterey, there are at least two alarming scenarios that concern experts about sinking nuclear power plants in war zones:
• Although reactors are very tough, their pools, which contain used-but-still-hot fuel rods, are not. If the cooling pool is damaged and stops working, the water will eventually boil, and these fuel rods will catch fire, spewing radioactive particles into the sky. This was a major concern of the Fukushima disaster.
• If a reactor shuts down, loses access to outside power and then loses its backup power, the coolant inside the reactor stops flowing. After a while, the fuel catches fire inside the reactor and releases hydrogen gas. “As we learned in Fukushima, it’s very dangerous,” Pollock said. In that disaster, hydrogen explosions blew off the roofs of the reactor buildings. This led to radioactive gas releases and massive evacuations.
There are at least three explanations for Russian forces attacking Zaporizhia at this moment in the week-old invasion of Ukraine, said Melissa Hanham, an open-source intelligence expert affiliated with Stanford University’s Center on International Security and Cooperation. The first is simply in the fog of war, with a Russian invasion force taking every facility in its path, leading to a shootout at the plant. The latter was a deliberate bid to control a high-risk site, similar to the takeover of Chornobyl at the start of the invasion. The IAEA complained that staff at Chornobyl were not compensated for monitoring operations there. A third explanation suggested by Ukrainian officials is that Russia intended to control and cut off electricity to the country as part of its invasion plan.
“If it’s under Russian control, you’re asking for some confidence-building by allowing the IAEA to have access and regular communication with whoever is running it, probably Ukrainian personnel,” Hanham said.