International Atomic Energy Agency experts unable to determine cause of fire at Ukraine’s Zaporizhzhya Nuclear Power Plant
Update 243 – IAEA Director General Statement on Situation in Ukraine

International Atomic Energy Agency (IAEA) experts at Ukraine’s Zaporizhzhya Nuclear Power Plant (ZNPP) today visited the plant’s cooling towers to observe the impact of yesterday’s fire.
Following its request to immediately assess the impact of the fire, the IAEA Support and Assistance Mission to Zaporizhzhya (ISAMZ) accessed the cooling tower area this morning. Based on the observations, the team assessed that it was unlikely that the primary source of the fire began at the base of the cooling tower, Director General Rafael Mariano Grossi said.
During the team’s visit to the cooling tower, it determined that the damage was most likely concentrated on the interior of the tower at the water nozzle distribution level, located at roughly ten metres high. The team has requested access to the water nozzle distribution level. It could observe the bottom of the water nozzle distribution level from the concrete foundation columns. The team could also see down into the cold-water basin, which is the base of the cooling tower, and has requested to access it as well. The team was not permitted to access these two locations during today’s walkdown for safety concerns.
Whilst visiting the impacted cooling tower, the team observed burnt areas in the internal equipment higher up, near the water nozzle distribution level. They also observed droplets of burnt plastic and fragments of fallen concrete distributed across the cold-water basin. The team assessed that these droplets were consistent with melted and fallen plastic mesh from the fire. Samples of the debris, including burnt and molten plastic, were collected. The lingering odour from the fire was assessed by the team and determined that in the absence of a sulphur smell, was more likely caused from burning plastic.
Neither tyre nor drone remains were observed during the walkdown.
The team confirmed that there were no significant signs of disturbance of the debris, ash or soot located at the base of the cooling tower.
The nuclear safety of the plant was not affected, as the cooling towers are not currently in operation. The cooling towers are not required as part of the cooling mechanism for the reactors, which are all in a state of cold shutdown.  No radioactive material is present in the area of the cooling towers, which is located approximately 1.5 kilometres from the reactor units at ZNPP. The team conducted radiation monitoring in the area of the cooling towers and the reactors and confirmed no signs of elevated radiation levels.
To gather additional information and verify the authenticity of the evidence, the ISAMZ team has requested to accompany ZNPP staff when they photograph the upper part of the water nozzle distribution level.
The team has not been able to draw definitive conclusions on the basis of the findings and observations so far. The IAEA will continue its overall analysis after additional review and access to the water nozzle distribution level and the cold-water basin.

https://www.iaea.org/newscenter/pressreleases/update-243-iaea-director-general-statement-on-situation-in-ukraine