Zaporizhzhia Nuclear Plant Relies on Emergency Power for 27th Time Since Invasion

How Long Can Diesel Generators Sustain the Plant?

Ukraine’s Zaporizhzhia nuclear power plant has operated without external electricity for more than a week, marking the 27th occasion since Russia’s full-scale invasion began that the facility has been forced to use emergency diesel generators to maintain critical safety systems. Located in southeastern Ukraine near the front lines, the plant remains under Russian control but continues to rely on Ukrainian technicians for its operation amid ongoing shelling and grid disruptions.

The loss of off-site power poses a serious risk to nuclear safety, as continuous electricity is essential for cooling reactors and spent fuel pools. Each time the external grid fails, diesel generators kick in automatically, but they are designed only for short-term use and require constant refueling and maintenance. Ukrainian officials have repeatedly warned that prolonged reliance on backup power increases the chance of mechanical failure or fuel shortages, especially amid active combat conditions that hinder resupply efforts.

What Are the Risks if Power Is Not Restored?

Emergency diesel generators at Zaporizhzhia can provide power for approximately 10 to 14 days before requiring refueling, depending on load and equipment condition. However, delivering fuel to the site has become increasingly difficult due to damaged roads, checkpoint delays, and the proximity of fighting. International atomic energy officials have stressed that while generators have so far prevented a loss of cooling, the situation remains precarious and unsustainable over the long term.

If external power is not restored and diesel supplies run low, the plant could lose the ability to circulate coolant through reactor cores and spent fuel pools, potentially leading to overheating, hydrogen buildup, or in extreme cases, a radiological release. Although all six reactors are currently in a cold shutdown state, reducing heat generation, they still require continuous cooling to prevent residual heat accumulation. The plant’s safety systems have multiple redundancies, but each layer depends on a functioning power supply.

Why does the plant keep losing external power? Repeated shelling and damage to transmission lines have severed or destabilized the connection to Ukraine’s national grid, forcing reliance on on-site backups.

Frequently Asked Questions

Are the reactors currently producing electricity? No, all reactors at Zaporizhzhia are shut down and not generating power; they are maintained in a safe, stable condition requiring only minimal energy for cooling and monitoring.

Is there a risk of a nuclear accident like Fukushima? While the risk is not zero, experts say the likelihood of a major release remains low due to the reactors’ shutdown status and multiple safety barriers, though prolonged power loss would significantly increase danger.