Grossi arrives at the Zaporizhzhia Nuclear Power Plant to assess its safety.

Rafael Mariano Grossi, the director general of the International Atomic Energy Agency, arrived at the Zaporizhzhia Nuclear Power Plant on Thursday following the destruction of a dam in southern Ukraine that is a major source of water used to cool the plant’s reactors. , endangered.

Energoatom, Ukraine’s nuclear power company, said in a message on the Telegram messaging app that Mr Grossi and a team from the United Nations nuclear agency IAEA had arrived at the Russian-occupied plant. Russian state news media too reported that mr. Grossi had reached the factory, which is close to the front line and inside the area controlled by Russian forces.

Mr Grossi said before his visit that he would cross the front line to investigate conditions at the plant and go through the facility for several hours. His journey was slightly delayed due to security concerns.

The facility, like other nuclear power plants, was designed to be resilient, but came under fire numerous times during the war. The most recent concerns arose last week when the destruction of the Kakhovka Dam on the Dnipro River caused water to drain from a reservoir that feeds a giant pond at the nuclear facility. Water from that pond is used to cool the power plant’s reactors to prevent a meltdown. Part of Mr. Grossi, he said, was to assess the water levels in the pond and how quickly the supply to it could be restored.

Estimates vary on how long existing water supplies can last in the pond, but Mr Grossi said on Tuesday there could be “water for a few weeks or maybe a month or two”.

An additional problem is the precise depth of the water remaining in the reservoir. Mr Grossi said there was a discrepancy between water level measurements at a thermal power station near the reactors and measurements in the reservoir itself. Knowing the water depth is important for calculations on how best to supply the cooling pond.

Oleh Korikov, Ukraine’s chief nuclear inspector, said the impact of the dam disaster on the nuclear power plant, the largest in Europe, was “significant”. He told reporters at a briefing on Wednesday that the plant is still safe to operate for now, but expressed concern over Russian troops occupying the site, who have subjected the plant’s Ukrainian engineers to difficult working conditions, stress and other abuses. .

Stabilizing the situation “would be possible if we had responsible management there, but unfortunately we don’t have that,” he said.