Europe's largest nuclear plant lies in the middle of a warzone, which is not, I think we can agree, ideal.
Until Ukraine and Russia reach an agreement, the plant remains in danger. “There’s no question: There should not be any military operations at the plant or in the vicinity of the plant,” says Ed Lyman, senior global security scientist at the Union of Concerned Scientists and coauthor of the bookBut, he continues, while neither military’s soldiers have deliberately fired on the plant, anything can happen in the fog of war.
When Russia invaded, Zaporizhzhya—which provides a fifth of Ukraine’s electricity—still had four out of its six reactors online. But after the conflict destroyed all but one of the plant’s external lines to the local power grid, plant operators shut down one, then two, and then three of the reactors this summer.
The plant has also been affected by at least three local power outages, which the IAEA attributes to the Russian shelling of nearby infrastructure. During these times, operators managed to keep the last reactor, unit number six, running by shifting to backup diesel generators, which have just a couple days’ worth of fuel in them.
But following a September outage, the operators decided it was time to also take unit six offline and put all the reactors into “cold shutdown” mode. That involves blocking the fuel rods in the reactor, which stops the nuclear fission reaction. That also drops the temperature of the rods and the water in the surrounding cooling pools, reducing the need for constant cooling.
Though the “cold shutdown” reduces risks, it doesn’t eliminate them. The pools containing spent fuel rods still need to stay cold enough to prevent the water from evaporating. If it does, it will expose the rods, which then react with air and release radioactive gases. (A similar problem has confronted workers at