Rafael Grossi spoke at the airport in Vienna after returning from a visit to Ukraine, where an IAEA inspection of the plant was carried out on Thursday.
He said that the IAEA team had given a red rating to the physical integrity of the facilities at Europe’s biggest nuclear power plant “because still we have been seeing military activity” nearby.
“I was able to see myself … impact holes, markings on buildings, of shells. This means that the physical integrity of the facility has been violated, not once, but several times,” Mr Grossi added.
Britain’s Defence Ministry said earlier on Friday that shelling was continuing near the power plant, and Ukrainian President Volodymyr Zelenskyy’s office said Russian shelling had damaged houses, gas pipelines and other infrastructure in the Nikopol region on the other bank of the Dnipro River following fighting that took place in several areas of eastern and southern Ukraine overnight.
The IAEA, braving gunfire and artillery blasts along their route, crossed the front lines to reach the Zaporizhzhia plant on Thursday in a mission to help safeguard the plant against catastrophe. The fighting in the area has underscored the urgency of their task.
Russia and Ukraine traded accusations over who was trying to impede the work of the IAEA experts.
As for the power plant’s safety and security systems, the IAEA gave a yellow rating, Mr Grossi said, because most of them are working “relatively well”.
However, he said that there have been interruptions to these systems — in part caused by physical damage at the plant.
There are some that “are not fully back in place, so we cannot get the full information”, Mr Grossi said.
“But it’s not a red — it means that the activity is continuing.”
Local Russian-appointed authorities said on Friday that staff at the Zaporizhzhia nuclear power plant restarted a key reactor hours after a shelling attack a day earlier forced it to shut down.
Ukraine’s nuclear energy operator, Energoatom, confirmed on its Telegram channel that the reactivated reactor had been plugged back into the power grid.