IAEA reps hear military actions or alarm sirens at all five Ukrainian NPPs almost every day last week

Over the past week, the IAEA team at the Zaporizhia NPP reported hearing military actions almost every day, and IAEA teams present at the Khmelnytsky, Rivne and South Ukraine NPPs and on the territory of the Chornobyl NPP also heard air raid sirens almost every day.

The agency reported this with reference to Director General Rafael Mariano Grossi on Monday.

In addition, on Thursday morning, the IAEA team in Chornobyl was awakened by the sounds of numerous explosions. Inspectors were later told that several drones had been spotted over the exclusion zone, approximately five kilometers from the facility, and the sounds the team heard were those of anti-aircraft fire.

“My position remains unchanged. I’m deeply concerned about the increased frequency of reported drone activity near nuclear facilities,” Director General Grossi said. “I renew my call for maximum military restraint to prevent a nuclear accident.”

Over the weekend, the IAEA team based at the ZNPP was informed of a newly constructed dam to isolate one of ZNPP’s channels from its cooling pond. This channel currently supplies water for the cooling of several plant systems, such as unit transformers that provide power to the site’s six reactor units, which is needed for the operation of their safety systems.

The ZNPP’s six reactors have been in cold shutdown since spring 2024 but still require cooling water for their safety systems, reactor cores and spent fuel pools.

While the ZNPP continues to use water from the groundwater wells on site for the cooling of these essential services, the dam was constructed to preserve the water in the channel to provide cooling for other plant systems that are needed to maintain the ZNPP in safe shutdown for extended periods of time.

The IAEA team has also been informed that the site is pumping water from the cooling pond into the isolated part of this channel and that the current water level in the channel is more than a meter above the point where cooling pumps would cease to operate. The ZNPP is also considering other options for supplying power to its reactor units to maintain the operation of its safety systems, as well as other measures for the cooling of the unit transformers.

“This underscores the ongoing challenges in ensuring reliable cooling water for the ZNPP’s six reactors and their safety systems needed to maintain long-term cold shutdown. The potential loss of cooling resulting from the depletion of the water in this ZNPP channel represents a real concern with respect to nuclear safety, which is a priority for the IAEA,” Director General Grossi said.

According to the IAEA, two of the nine power units at Ukraine's three operating nuclear power plants are shut down for maintenance and refueling, which also includes work on some external power lines.

Over the weekend, two reactors had reduced power levels due to power grid constraints - both have now returned to nominal power levels.