How much more perilous can the situation at Zaporizhzhia nuclear power plant become?

By Linda Pentz Gunter

Luck is not a sound basis on which to rely when we are dealing with nuclear risks. But luck is again what me must depend on as we watch and wait for the worst to happen — or not — at the six-reactor Zaporizhzhia nuclear power plant in Ukraine.

The plant, located in the southwestern region of the country — the area most directly embroiled in some of the most intense fighting, and with parts of it already “annexed” by Russia — has already experienced some frightening near-misses. These include shelling and missile attacks and frequent losses of offsite power that, if not restored promptly, could lead to a meltdown.

The plant has been occupied by Russian forces since March 4, 2022. Rumors abound that a severely depleted workforce is laboring under stressful and even violent conditions, while other staff have fled or have disappeared.

Now we learn that mass evacuations are underway from communities close to the nuclear plant. These include residents of Enerhodar, the city that houses most of the plant workers and their families.

An estimated 3,000 people, including 1,000 children, have already reportedly evacuated, although where to is unclear. Some Ukrainian sources have suggested this is effectively a “kidnapping” or even “deportation” exercise, with evacuees being taken deeper into Russia.

There are conflicting reports about whether any plant workers number among the evacuees. Energoatom, the Ukrainian nuclear energy authority, claims that as many as 2,700 plant workers are being relocated to Russia, leaving the plant dangerously understaffed. 

These conditions could lead to human error, a leading cause of accidents, including the nuclear power plant disasters at Three Mile Island and Chornobyl.

Fears of a Ukrainian offensive designed to recapture some or all of the Russian-held territory appear to have prompted the sudden evacuation. But are people evacuating away from the conflict or from the prospect of a catastrophic outcome at the nuclear power plant, should it become fully engulfed by the fighting? And if that does happen, what might the consequences be?

As a precaution, all six Zaporizhzhia reactors are currently shut down — officially their status is called “cold shutdown”, which is not as final as it sounds and does not mean they are out of danger. 

The fuel in the reactor core still requires electricity to power cooling, as do the pumps that supply cooling water to the fuel pools. This means a meltdown is still possible. Cold shutdown just buys workers more time to restore power should it become lost, but a reliable supply of electricity to the site is still essential to avoid disaster.

Bombardments of the electrical grid have already knocked out power to the plant on several occasions, forcing workers to hook up backup diesel generators. There is a healthy supply of these at the site, but they need refueling. If the plant is in the midst of an active war zone, fresh fuel deliveries may be delayed or even impossible. At which point, time runs out and disaster begins.

The consequences of such an outcome would be drastic not only for the people of Ukraine and neighboring Russia, but for all of Europe, should any or all of these reactors melt down or suffer a fuel pool fire. We only have to look at the fallout map from the 1986 Chornobyl disaster, a single unit with a far smaller radioactive inventory, to understand the potential scale of such a tragedy.

Chornobyl contaminated 40% of the European landmass with long-lived radioactive fallout and created an effectively permanent 1,000 square mile Exclusion Zone around the stricken nuclear site. 

Beyond electrical power, water supply is also essential to keep nuclear power plants out of danger. The thermally and radioactively “hot” irradiated fuel rods sitting in cooling pools, must stay submerged. Electrically powered pumps can maintain a steady water supply. But access to water is critical.

In late March, alarms were raised about a dramatic drop in water levels at the reservoir that supplies cooling water to the plant. Ukrainian officials said the Russians had drained the reservoir, increasing the risk of a meltdown at Zaporizhzhia.

But this month, headlines warned that record high water levels could threaten a dam that, if breached, would send floodwaters pouring onto the nuclear site, inundating the plant’s pumping systems.

War, flooding, and human error are all potential disasters waiting in the wings that could trigger a nuclear catastrophe. But what can prevent it?

“We must act now,” said International Atomic Energy Agency director general, Rafael Grossi. But what is his plan? IAEA efforts at creating a “safe zone” around the Zaporizhzhia reactors, where no fighting could then occur, have collapsed. On the geopolitical stage, both Russia and Ukraine appear to harbor the conviction that their side can win the war. NATO and its allies show no signs of insisting on a diplomatic solution, given the benefit to those countries of a Russian defeat.

All of this brutality already comes at immense cost to the population of Ukraine, but also to Russia, where mothers, too, are losing sons to an unnecessary war. A major strike on Europe’s largest nuclear power plant would extend that tragedy across thousands of miles, affecting hundreds of millions of lives. All we’ve got between us and that disaster is luck, which, like the deadly uranium that fuels nuclear power plants, will eventually run out.

Linda Pentz Gunter is the international specialist at Beyond Nuclear and writes for and curates Beyond Nuclear International. 

Headline photo of war destruction in Ukraine by Alex Fedorenko on Unsplash