Zaporizhzhya nuclear plant reconnects to grid after IAEA-brokered ceasefire ends 30-day blackout

Ukraine’s Zaporizhzhia Nuclear Power Plant, the largest nuclear facility in Europe, is back on the grid. The plant reconnected to external power on June 13 after spending nearly 30 days running on emergency diesel generators, a precarious situation that required a ceasefire brokered by the International Atomic Energy Agency to resolve.

IAEA Director General Rafael Mariano Grossi confirmed that the repaired 750 kV Dniprovska power line was energized at 09:30 local time and fully restored by 13:00. The outage, triggered by an attack on a nearby electrical substation in late May, was the longest the plant has endured since Russia’s full-scale invasion began in 2022.

A nuclear plant held together by temporary truces

This was the 19th total loss of off-site power at the Zaporizhzhia plant since the war began.

The ceasefire that enabled repairs was the sixth temporary “window of silence” negotiated by the IAEA since late 2025. IAEA teams were on site monitoring repair work starting the weekend before the reconnection. The ceasefire allowed crews to complete demining operations and fix critical infrastructure, including the Dniprovska line and another connection called Ferosplavna-1.

Both Rosatom, the Russian state nuclear energy corporation that has effectively controlled the plant since early in the conflict, and Ukrainian operators voiced ongoing safety concerns throughout the ceasefire period.

The broader energy security picture

Before the conflict, ZNPP supplied roughly a fifth of Ukraine’s electricity. Its six reactors have been in cold shutdown since the early stages of the war, meaning they aren’t generating power for the grid. But they still require constant external electricity to maintain cooling systems and prevent radioactive contamination.

The fact that the IAEA has now brokered six separate ceasefires specifically for power-line maintenance speaks to both the agency’s diplomatic evolution and the grinding repetitiveness of the crisis. Director General Grossi has positioned the IAEA as something it was never really designed to be: a wartime mediator with nuclear stakes.

What this means for energy markets and investors

For investors watching European energy exposure, the key metric to track isn’t whether the plant reconnects after each outage. It’s how long each outage lasts compared to the previous one.

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