Piercing the fog of war at Ukraine’s embattled Zaporizhzhia Nuclear Plant

After plumbing Ukraine’s lightning fast leap to unplug from Russia’s power grid and a pair of exposés exposing Russian moles within its nuclear energy utility, my latest reporting on the #EnergyFront refocused coverage of the warfare threatening Europe’s largest nuclear power plant. While domestic and international reporting focused on the terrifying explosions rocking Zaporizhzhia — a perilous game of nuclear roulette — my stories spotlighted efforts by Ukrainian nuclear experts to cancel the game, and thus slash the risk of devastating reactor meltdowns.

Few stories questioned why Zaporizhzhia was still producing power in the middle of a war zone. U.S. reactors proactively shut down when, for example, a hurricane is barreling in. Why was Ukraine’s nuclear utility and energy ministry and nuclear regulator ordering Zaporizhzhia’s operators to do otherwise, and why was its nuclear regulator allowing it? The answer: Ukraine wanted to maximize its power supply to bolster electricity exports to Europe in a bid for political support and badly-needed revenue.

But nuclear experts I spoke to, such as former Chernobyl chief engineer and IAEA board member Nikolai Steinberg, called maintaining nuclear chain reactions at Zaporizhzhia “a crime.” Shutting down, Steinberg and others argued, would cool Zaporizhzhia’s reactors, thus slashing the risk of an accident akin to (or potentially worse than) Japan’s Fukushima disaster.

My first story laid out the experts’ case for a proactive shutdown. For example, I cited an unpublished assessment by Ukraine’s state nuclear-safety center reviewing the risk of a station-wide blackout that would zap the plant’s ability to cool its reactors and pools of spent nuclear fuel (as occurred at Fukushima in 2011). Moving Zaporizhzhia’s reactors to a ‘cold stop’, they found, would reduce accident risk by extending the time between station blackout and reactor core damage from 3 hours to 27 hours, buying crucial time for operators to find workarounds and restart cooling.

Shutting down proactively would also cease the production of short-lived fission products, reducing the harm caused by any reactor breach.

I followed up one week later after shelling (most likely by the Russian forces occupying the plant) forced the entire plant off the grid for the first time since it began operating in 1985, and temporarily shut down two reactors. My story explained how:

  • Repeated damage to Zaporizhzhia’s transmission lines — the electrical umbilical cords linking it to Ukraine’s grid — caused the plant’s reactors to blink on and off the grid.
  • The near misses bolstered calls for an orderly shutdown, even if diesel generators and other emergency systems had averted radiological accidents; and
  • Ukrainian officials continued to restart reactors and power generation rather than heed the warnings.

My story also noted, however, that nuclear experts had scored one win. Ukraine’s nuclear regulator took a symbolic baby step by ordering two reactor units already in cold shutdown to remain offline.

A few days later after that story the White House called for a “controlled shutdown” at Zaporizhzhia. Ukraine’s nuclear utility Energoatom acceded to the growing chorus on September 11.