IAEA Reports Heavy Attack on Zaporizhzhya Thermal Power Plant Switchyard Raising Nuclear Safety Concerns at ZNPP

UKRAINE — On the morning of June 4 the switchyard at the Zaporizhzhya Thermal Power Plant came under heavy attack, according to information the Zaporizhzhya Nuclear Power Plant provided to the International Atomic Energy Agency.

The IAEA team at the ZNPP observed light smoke rising from the direction of the ZTPP and heard sounds of military activity. ZTPP staff are sheltering as a result of the attack.

The incident has raised serious concern about the ZNPP’s sole remaining off-site power line, which in recent weeks has been disconnected several times, leaving the plant reliant on emergency diesel generators to cool its six reactors and prevent a nuclear accident.

For now, the power line remains connected but the incident comes amid repeated threats to the plant’s external power supply.

In a separate incident on June 3 the ZNPP lost off-site power for approximately 20 minutes after a drone strike on the Nikopolska substation across the Dnipro River. That marked the 17th such temporary loss during the conflict. Emergency diesel generators supplied power until the line was restored shortly before midnight.

Russian Aerial Attacks Across Ukraine June 2-4

In separate incidents during the nights of June 2 and 3, Russian forces launched large-scale combined drone and missile strikes targeting multiple Ukrainian cities and infrastructure, including areas in Zaporizhzhia Oblast.

Ukrainian air defense forces reported intercepting the majority of more than 600 drones and dozens of missiles launched in one wave, but strikes hit residential buildings, industrial sites, and energy infrastructure in Kyiv, Dnipro, Kharkiv, Zaporizhzhia, Odesa, and other oblasts.

Ukrainian state energy operator Ukrenergo reported power outages in several oblasts including Zaporizhzhia following the attacks. On June 4 a separate Russian drone strike hit a residential building in Kherson, injuring a 12-year-old boy.

Ukrainian forces conducted their own strikes in occupied Zaporizhzhia Oblast around the same period, including drone attacks on a Russian dry cargo ship in the port of Berdyansk assessed to have occurred on or around May 31.

Implications for Nuclear Safety and IAEA Position

The IAEA Director General Rafael Grossi has expressed deep concern about the reported attack on the ZTPP and stated that it must stop immediately to avoid the danger of an extended loss of power incident at the ZNPP.

The agency continues to emphasize that military restraint is required to prevent a nuclear accident. The presence of an IAEA team at the site provides ongoing independent observation and reporting capability.

The six reactors at the ZNPP remain shut down. Safety systems depend on a continuous supply of electricity for cooling.

Prolonged reliance on diesel generators increases operational risks related to fuel logistics, equipment fatigue, and the potential for concurrent failures during an emergency.

The IAEA has previously noted that the plant’s off-site power configuration has been reduced to a single line for a sustained period, making any threat to that line a high-priority nuclear safety issue.

Official Statements

• IAEA – International Atomic Energy Agency, June 4, 2026: “The IAEA has been informed by the Zaporizhzhya Nuclear Power Plant (ZNPP) that the nearby Zaporizhzhya Thermal Power Plant (ZTPP) – whose switchyard helps deliver electricity to the ZNPP – has been under heavy attack this morning. The IAEA team at the ZNPP saw light smoke coming from the direction of the ZTPP and heard the sound of military activity. The incident raises serious concern about the ZNPP’s sole remaining power line, which in recent weeks has been disconnected several times, leaving the plant entirely reliant on emergency diesel generators for the electricity it needs to cool its six reactors and avoid the threat of a nuclear accident. For now, the power line is still connected. ZTPP staff are currently sheltering due to the attack, according to the information. DG @rafaelmgrossi expresses deep concern about the reported attack and says it must stop immediately, to avoid the danger of an extended loss of power incident at the ZNPP.”

• IAEA – International Atomic Energy Agency, June 3, 2026: “For the 17th time during the military conflict, the Zaporizhzhya NPP temporarily lost off-site power overnight. The power outage was caused by a drone strike on the Nikopolska substation on the other side of the Dnipro river from the ZNPP, leading to the temporary disconnection of the site’s only remaining power line for about 20 minutes. The ZNPP’s emergency diesel generators provided electricity until the line was reconnected shortly before midnight. The incident once again underlines constant dangers to nuclear safety during the war, DG @rafaelmgrossi says, reiterating necessity of military restraint to avoid the risk of a nuclear accident.”