Renewed shelling in the early hours of 21 September at the site of Ukraine’s Zaporizhzhia Nuclear Power Plant (ZNPP) damaged cables providing electricity to one of its six units, temporarily forcing the reactor to rely on emergency diesel generators for the power it needs for essential safety functions, the International Atomic Energy Agency (IAEA) was informed at the site by senior Ukrainian operating staff.

Two of the three emergency diesel generators of reactor unit 6 started automatically and operated for about 40 minutes following the shelling that occurred at 01:13am local time near the unit’s turbine hall which is next to the reactor building. They were no longer needed after the operator was again able to access external electricity for unit 6 from the ZNPP’s existing main power line, through the switchyard of the nearby thermal power station.

The ZNPP’s five other reactors were not affected, continuing to receive power directly from the plant’s off-site power line that was restored the previous week. Work is under way to repair the damaged cables of unit 6, IAEA said, as are efforts to restore this unit’s direct connection to the ZNPP’s external power line. The ZNPP’s six reactors are all in a cold shutdown state but still require power for maintaining cooling and other vital safety functions.

Director General Rafael Mariano Grossi – who was at the United Nations in New York for high-level consultations regarding his proposal to establish a nuclear safety and security protection zone around the ZNPP – said he was gravely concerned about the latest shelling at the site. He stressed the importance of the IAEA’s presence at the site to observe and report about such incidents in an impartial and independent manner. Grossi reiterated that the IAEA team present at the site for the past three weeks were able to transmit information directly to Agency headquarters in Vienna and conduct their activities without any impediment, restriction or interruption.

IAEA said the latest incident came after another shelling episode on 20 September, at one of the ZNPP site’s spray cooling ponds, which are part of the plant’s heat removal system. The pipe was damaged, taking the pond out of service pending repairs. There were also reports of shelling at the industrial site around the thermal power station, located a few kilometres from ZNPP.

“This once again demonstrates the urgent necessity to establish such a zone around the ZNPP. Until yesterday, there seemed to be less shelling at or near the plant, but this latest episode shows that the danger remains very real. It hasn’t gone away, and we can’t afford to lose any more time,” Grossi said. “I’m determined to do everything I can so that the nuclear safety and security protection zone around ZNPP becomes reality very soon. My high-level meetings at the United Nations this week are crucial to achieve this objective that is of paramount importance in preventing a severe nuclear accident from happening.”

On 21 September, Grossi discussed the situation around ZNPP with Russian Foreign Minister Sergey Lavrov in New York, during the 77th session of the UN General Assembly. Following the meeting, Grossi said the nuclear power plant must be protected, regardless of a planned referendum in the Zaporizhzhia region to determine whether it should become part of the Russian Federation.

He told journalists: "There are many factors involved. We hope that we will get from him [the President of the Russian Federation] and from everyone the support that is needed to ensure security at this station. A nuclear incident is not in anyone's interest. Regardless of whether there will be a referendum or not, we must protect the station. Now it is not protected." However, he added that the IAEA had started negotiations with Russia and Ukraine on the parameters of a safety zone around the plant.

"I am working here to create a security zone around the NPP. We are working very hard. I have already met with [Russian] Foreign Minister Sergey Lavrov, [Ukrainian] Foreign Minister Dmytro Kuleba, and [French] President Emmanuel Macron and the foreign ministers of the G7 countries, " he told journalists.

Following his meeting with Grossi, Lavrov said that Russia confirms its intention to continue cooperating with the IAEA. "Sergey Lavrov confirmed the Russian side's intention to continue close cooperation with the IAEA in order to force the Kiev regime to immediately stop shelling the nuclear power plant and its adjacent territories, including the city of Energodar, where ZNPP employees and their families live," the Russian Foreign Ministry's Telegram channel reported.

"I am working here to create a security zone around the NPP. We work very hard. I have already met with [Russian] Foreign Minister Sergey] Lavrov, [Ukrainian] Foreign Minister Dmytro] Kuleba, and [French] President Emmanuel Macron. Macron and the foreign ministers of the G7 countries," he said at a briefing for journalists.

Both Russia’s Defence Ministry and the (pro Russian) civil-military administration in Energodar reported especially heavy shelling of ZNPP in 20 and 21 September. The ministry noted that shelling by the Armed Forces of Ukraine was conducted from firing positions near the village of Marganets. According to the Energodar administration, a special building, a cooling system and a canteen on the territory of ZNPP were damaged by Ukrainian shelling. It noted that there were no casualties among the employees of the station or the Rosgvardiya military personnel guarding the perimeter.

Commenting on the damage sustained by the NPP, the adviser to the head of Russian nuclear utility Rosenergoatom, Renat Karchaa, told Interfax: “A pipe in one of the reactor cooling pools is damaged. But when the reactor is in a cold state, regulations stipulate the need for the operation of only two pools. Therefore, the hit, of course, is extremely unpleasant, but there are still two cooling pools, and this fully complies with the regulations, so it is impossible to call the situation critical." However, if the reactor were in operation, then, according to the regulations, specialists would have 72 hours either to repair the damage or to stop the power unit, he explained.

Ukrainian nuclear utility Energoatom said Russia was responsible for the shelling. Energoatom said in a statement that as a result equipment linking the ZNPP unit. 6 to the open switchgear was damaged. “Due to the loss of power, there was an emergency start of two diesel generators of the safety systems to ensure the operation of the fuel cooling pumps.” However, after the damage was repaired, “the diesel generators of unit 6 were turned off and put into standby mode”.

ZNPP is the largest nuclear power plant in Europe with six VVER-1000 units. Since February it has been controlled by the Russian army but continues to be operated by Ukrainian staff supported by experts from Russia’s Rosenergoatom. An IAEA mission led by Grossi visited the plant on 1 September and the Agency has maintained a presence there ever since. On 11 September, the last working reactor was stopped because of intense shelling and the plant has since been in cold shutdown.

Image: Renewed shelling has caused more damage to Zaporizhzhia NPP (courtesy of IAEA)