The occurrence of intense fires near Ukraine's Zaporizhzhya Nuclear Power Plant (ZNPP) continues to add to the growing challenges facing Europe's largest nuclear power plant (NPP), IAEA Director General Rafael Mariano Grossi said today.
On several occasions over the past week, the IAEA Support and Assistance Mission to Zaporizhzhya (ISAMZ) observed several fires at various distances from the ZNPP and nearby villages. Over the weekend, the IAEA experts observed smoke coming from an area to the north of the ZNPP near the ZTPP inlet channel. The plant confirmed that the fire was underneath the overhead cables of the Dniprovska 750 kilovolt (kV) line and the Ferosplavna 1 330 kV back-up power line - the last two remaining external power lines for the ZNPP.
As the summer heat continues, such fires along the pathways of the two remaining lines place the ZNPP at risk of loss of external power. While there was no disconnection of either line on this occasion, the situation highlighted the fragility of off-site power at the ZNPP.
"The off-site power supply to the ZNPP remains vulnerable, and any threat to the operability of the last two power lines is extremely concerning," said Director General Grossi. "Despite all reactors remaining in a cold shutdown state, the reliability of off-site power is still a major risk to nuclear safety and security at the ZNPP and action must be taken to protect these remaining lines."
This most recent event follows fires that occurred over the past few months. In early July the IAEA experts observed thick smoke and heard explosions coming from near the plant's 750 kilovolt (kV) switchyard which had allegedly been caused by drones hitting an adjacent forest, starting fires in windy conditions. Previously in late May, the IAEA team also reported a wildfire south of the same switchyard. During a walkdown to the 750 kV switchyard last week, the IAEA experts observed burned bushes and trees in the area outside the switchyard's perimeter and reported that there was no other impact from these fires.
This week, a new rotation of experts crossed the frontline to replace colleagues who have been stationed there for the past several weeks. This marks the 22nd IAEA team at the site since Director General Grossi established the mission on 1 September 2022. The IAEA teams continue to hear explosions at various distances from the site.
On Sunday, staff at the ZTPP were allegedly unable to go outside to start the pump that transfers water from the ZTPP inlet channel to the ZTPP discharge channel for some time due to the risk of shelling. The transfer is important as it then provides a supply of water to the sprinkler ponds and other areas. ISAMZ was informed that the pump was later turned back on and there was no impact to nuclear safety at the ZNPP.
On Wednesday, it was confirmed that all four diesel steam generators commissioned in January 2024 to provide the steam required by the ZNPP to process liquid radioactive waste have been put into operation. The ZNPP reported that approximately 1000 cubic metres of accumulated radioactive waste water will be processed over the next 10 to 12 days.
The IAEA experts also continue to monitor crucial maintenance activities across the site. On Friday, the safety train of unit 1 and its emergency diesel generator were placed back into standby mode following the completion of planned maintenance. Maintenance work continues on the safety systems of unit 6, and also on the main transformer of unit 3. Additionally, one of the breakers for the automatic transformer, which connects the ZNPP 750 kV switchyard to the ZTPP 330 kV switchyard, was placed under maintenance.
Last week, the IAEA experts assessed the status of several of the site's 20 emergency diesel generators (EDGs), which serve as the last line of defence in the event of a loss of off-site power at the ZNPP. The IAEA team observed that the EDG for a safety train in unit 5 was started safely during scheduled testing. During a visit to the offsite diesel fuel storage last week, the team was informed by the ZNPP that the reduced storage of diesel fuel is due to upcoming planned maintenance of the storage tanks.
During their regular walkdowns to monitor nuclear safety and security, the IAEA team visited the Dry Spent Fuel Storage Facility and the offsite ZNPP Central Warehouse. They also met with representatives of the ZNPP safety analysis service, who informed them that the focus of the group's work is on decay heat calculation analysis, given that all reactors are in cold shutdown.
Elsewhere in Ukraine, the IAEA experts present at the Khmelnytskyy, Rivne and South Ukraine NPPs and the Chornobyl site reported continued air raid alarms due to ongoing military activity in the regions on several days over the past week. On Friday, the IAEA experts at the Chornobyl NPP successfully rotated with the new team.
The teams at the Khmelnytskyy and Rivne NPPs reported that the operation of these plants continued to be affected by the impacts of the armed conflict on the electrical infrastructure of Ukraine. The IAEA teams were informed that the power levels of some reactor units were temporarily lowered due to grid limitations.
"The vulnerability of the electricity infrastructure across the country remains very concerning. It is essential that the electricity network across all of Ukraine remains stable to help maintain nuclear safety at all nuclear power plants," Director General Grossi said.
Separately this week, as part of the IAEA's efforts to support Ukraine in maintaining nuclear safety and security during the armed conflict, the Agency arranged its 57th delivery of nuclear safety and security related equipment. The delivery consisted of IT equipment for the radiation monitoring network and analytical laboratories of hydrometeorological organizations of the State Emergency Service of Ukraine. The delivery was supported with funding from Sweden.
