ZAPORIZHIZHIA, UKRAINE — The International Atomic Energy Agency has expressed ‘grave concern’ over Russia’s capture of the Zaporizhzhia [g]nuclear power plant, the largest in Europe.
In a Friday statement cited by CNN, Ukraine's State Emergency Services said a training building outside the main reactor complex caught fire after shelling from Russian military forces, while the State Nuclear Regulatory Inspectorate said that although the plant's six reactors remained intact, compartment auxiliary buildings for Reactor Unit 1 had been damaged.
Experts speaking to science journal Nature have cautioned against comparisons to the 1986 disaster at Chernobyl, however, because unlike at Chernobyl each reactor sits within both a massive reinforced-concrete containment structure, and is enclosed in a pressurized steel vessel.
Additionally, The Guardian explains that the Chernobyl disaster was caused by a graphite fire which sent a radiation plume across Europe, while The Zaporizhzhia plant uses pressurized water reactors, which do not involve graphite.
One issue that does remain, though, is that according to Nature, as the attack took place, five of Zaporizhzhia’s six reactors had been shut down.
The problem here is that uranium nuclei in used fuel rods break up, and as a result radioactive isotopes can accumulate and produce heat even after a shutdown.
To mitigate against this, shutdown reactor cores still need to be cooled, which requires power, and if the reactors’ active cooling suddenly stopped, the plant could face a scenario similar to that at the Fukushima Nuclear Power Plant in Japan, when power was cut off after the March 11, 2011 earthquake and tsunami, and three reactors melted down.
Even this scenario is unlikely, however, as one nuclear safety researcher at the University of Tokyo explained that the Ukrainian plant has several alternative cooling systems, and experts told Nature that even if a reactor core were to melt down, “it might not cause a major release of radioactive materials.” Elsewhere, strategically, having taken Zaporizhzhia, Ukrainian President Volodymyr Zelensky has now warned Russian forces will attempt to capture the Yuzhnoukrainsk [h]nuclear power, according to The Associated Press.
