The Zaporizhzhia nuclear plant is located on the war's frontlines, and is often caught in shelling and firing between Ukraine and Russia.
The Russian-occupied Zaporizhzhia nuclear power plant in Ukraine was cut off from the power grid on Monday and relied on emergency generators to cool the nuclear fuel.
Shortly after the outage, Ukraine reconnected the plant to its external power supply. Ukrenegro, the state national grid operator, declared that repair work was carried out, stating that "the station is switching (back) to power supply from the Ukrainian power system".
Ukraine's state-owned nuclear energy company, Energoatom, declared that the emergency generators had enough fuel to last for around ten days. The plant lies close to the war's frontlines in southern Ukraine and has often been caught between heavy firing and shelling. This was the seventh power supply outage at the facility since Russia invaded Ukraine in February 2022.
The power outage affected nearly 250,000 consumers in the Zaporizhzhia region.
"The nuclear safety situation at the plant is extremely vulnerable," Rafael Grossi, head of the International Atomic Energy Agency, said in a tweet.
Energoatom blamed Russia, saying the outage was caused by shelling. A Russian official, however, claimed that Ukraine had disconnected a power line. Disruptions in the power supply can disable the cooling systems essential for the reactor's safety.
In his appeal, Grossi called for the area around Zaporizhzhia to be spared from fighting, saying: "We must protect (the) plant now; this situation cannot continue."
The six nuclear reactors in the plant are protected by a shelter to bear the impact of shells or rockets. There are fears that artillery fire or an explosion could fuel a disaster like the 1986 Chernobyl meltdown. Energoatom warned that the facility is "on the verge of a nuclear and radiation accident".
The nuclear plant employed more than 11,000 people before the invasion, 6,000 of whom remain at the site. A representative of Energoatom said the Russian officials are training the personnel for the evacuation of 3,100 staff and their families.