In his latest update on the situation at the Zaporizhia NPP (ZNPP), International Atomic Energy Agency (IAEA) Director General Rafael Mariano Grossi said powerful explosions had shaken windows at the site, “underlining the urgent need for maximum military restraint to reduce the danger of a nuclear accident as the conflict enters its third year”.

IAEA experts stationed at ZNPP reported hearing explosions every day over the week, including one that appeared to occur close to the plant itself. There were also several explosions, one of which was unusually loud, indicating very close proximity to the site. IAEA said it was not possible to conclusively determine the origin or direction of the blasts, with the exception of the loud explosion, which according to the ZNPP was part of “field training” with no shelling of the plant nor any damage to it. There were no physical injuries or casualties, the plant added. ZNPP separately informed the IAEA team that a mine had exploded outside the site perimeter without causing damage or injury.

Russia took control of ZNPP in March 2022 as part of its special military operation in Ukraine. In October 2022, Russian President Vladimir Putin signed a decree formally transferring ZNPP to Russian jurisdiction under nuclear utility Rosenergoatom (part of Rosatom). A Russian Federal State Unitary Enterprise. Zaporizhia NPP was established by Rosenergoatom to operate the plant and is now transferring the plant to Russian operating and safety standards.

“I remain deeply concerned about the nuclear safety and security situation at Europe’s largest nuclear power plant, located on the frontline of the war. The reports of our experts indicate possible combat action not far away from the site. Once again, I call on all parties to strictly observe the five concrete principles for the protection of the plant and avoid any attack or military activity that could threaten nuclear safety and security there,” Grossi said.

In another indication of persistent nuclear safety and security risks facing ZNPP, the site remains without back-up power, three days after connection to its last 330 kilovolt (kV) line was cut due to a problem that occurred on the other side of the Dnipro River [in Ukrainian controlled territory].

ZNPP is still receiving the electricity it needs for reactor cooling and other nuclear safety and security functions from its only remaining 750 kilovolt (kV) line, but it currently has no back-up options available for off-site power. ZNPP said it had been informed by the Ukrainian grid operator that the 330 kV line was not expected to be reconnected to the site before 1 March. “This situation leaves the plant very vulnerable to further disruptions in the supply of off-site power. It is essential that the back-up power line becomes available again as soon as possible,” Grossi emphasised.

Earlier, the IAEA team went to the site’s 750 kV electrical switchyard and observed that its status was unchanged since a previous visit last month. In addition to the single line that remains connected, the team saw spare parts for the repair of a second line, out of four 750 kV lines before the conflict. However, the site has no plans to start the repair work due to the conflict.

The IAEA team has observed the periodic testing of one of the emergency diesel generators at reactor unit 4, the last line of defence to provide the electricity needed in case of a loss of all off-site power. This has happened eight times since the start of the armed conflict.

The IAEA experts also met with ZNPP’s electrical department to discuss the maintenance plans for the year and also visited the electrical control room where they could observe the status of the on-site and off-site power systems. The IAEA experts were informed that all ageing cabling and equipment related to the safety systems, including switchboards and batteries, have been replaced.

The team performed a walkdown of all six main control rooms in the reactors and was able to collect safety parameters in reactor units 2, 3 & 4 . They had the opportunity to view the regulatory authorisations of personnel. The team was informed that many of the operating staff present were in the process of transitioning from their Ukrainian licenses to “authorisations” issued by Rosteckhnadzor, the nuclear regulator of the Russian Federation.

Earlier, Grossi issued a statement on ZNPP as the military situation deteriorated. He reiterated his call for maximum restraint and strict observance of the five concrete principles established by him at a meeting of the United Nations Security Council on 30 May 2023. He particularly emphasised the need to protect, at all times, the physical integrity of the ZNPP and avoid any attack or military activity that could impact the safety and security of the facility.

Meanwhile, ZNPP Communications Director Yevgenia Yashina said there is no threat to the safety of the plant due to the shutdown of the backup power line. However, she expressed concern at the delay in its repair. "The Ukrainian side has notified us that the repair work on the 330 kV Ferroalloy-1 line will be completed no earlier than 1 March, which causes concern, since repairs usually take 1-2 days," she told TASS. She also clarified she had notified the IAEA about this.

Image: The Zaporizhia nuclear plant