The European Union and the United States have in recent days called for the creation of a demilitarized zone around the Zaporizhzhya nuclear power plant in southern Ukraine, as shelling at the plant increases the risk of a nuclear accident.
While such plants are designed to withstand a range of risks — from a plane crashing into the facility to natural disasters — no working nuclear power plant has ever been in the midst of active combat, and it wasn’t designed with the threat of cruise missiles in mind.
The concrete shell of the site’s six reactors provides strong protection, as was the case when reactor No. 1 was hit in March, officials say. More troubling is the chance of a transformer being hit by shelling, increasing the risk of fire.
If a fire broke out at the current transformers and the grid was taken offline, it could cause a failure in the plant’s cooling system and lead to a catastrophic meltdown, said Edwin Lyman, a nuclear energy expert with the Union of Concerned Scientists. , a private group in Cambridge, Mass.
He noted that the loss of coolant during the Fukushima accident in Japan in 2011 had caused three reactors to undergo some degree of meltdown.
If the cooling is interrupted, said Dr. Lyman, the nuclear fuel can become hot enough to melt in a matter of hours. Eventually, it could melt through the steel reactor vessel and even the outer containment structure, releasing radioactive material.