Ukraine's Zaporizhzhya Nuclear Power Plant (ZNPP) has once again lost the connection to its only remaining back-up power line, underlining the continued fragility of the electrical grid during the military conflict, Director General Rafael Mariano Grossi of the International Atomic Energy Agency (IAEA) said today.
The latest disconnection of the 330 kilovolt (kV) power line - which occurred just before noon local time on Wednesday - left the plant entirely dependent on its last functional 750 kV power line for the electricity it needs to cool its reactors and for other essential nuclear safety and security functions. According to Ukraine's Ministry of Energy, the disconnection occurred as a result of military activities.
"A secure supply of off-site power from the grid for all nuclear sites is one of the seven indispensable pillars of nuclear safety and security that we outlined early in the war. It is obvious that this supply is far from being secure. The vulnerability of the grid remains a deep source of concern for nuclear safety at the Zaporizhzhya Nuclear Power Plant as well as elsewhere in Ukraine," Director General Grossi said.
Before the conflict, the ZNPP had access to a total of ten external power lines, both 750 and 330 kV. The site has lost all off-site power eight times during the conflict.
The IAEA team based at the ZNPP continued to hear explosions at distances far away from the site on several days over the past week.
The team has continued to monitor and assess nuclear safety and security at the plant, in recent days conducting a site walkdown, confirming the water levels in the sprinkler ponds, and observing the testing of an emergency diesel generator. The team also visited the nuclear safety related electrical breakers and instrumentation, and control cabinets of units 3 and 4.
Director General Grossi said he was in daily contact with both sides to organize the next rotation of IAEA experts at the ZNPP. The current team, ISAMZ27, has been at the plant for more than two months now. The previous rotation, conducted in early March, was also delayed because of difficult conditions on the ground.
"The IAEA's continuous presence at the Zaporizhzhya Nuclear Power Plant, since September 2022, has been of vital importance for our efforts to help prevent a nuclear accident during the war. However, getting our staff to and from the site - located on the frontline - has become more complicated in recent months. In the coming days, I will continue to engage intensively with both sides to find a solution, which is urgently needed. My overarching priorities are the safety of my staff and the Zaporizhzhya Nuclear Power Plant," Director General Grossi said.
At the Chornobyl site, investigations to determine the extent of damage sustained by the New Safe Confinement (NSC) arch are ongoing following the drone attack in mid-February.
It took several weeks to completely extinguish the fires caused by the strike. The emergency work resulted in approximately 330 openings in the outer cladding of the NSC arch, each with an average size of 30-50 cm.
According to information provided to the IAEA team at the site, a preliminary assessment of the physical integrity of the large arch-shaped building identified extensive damage, for example to the stainless-steel panels of the outer cladding, insulation materials as well as to a large part of the membrane - located between the layers of insulation materials - that keep out water, moisture and air.
In addition, the IAEA team was informed that the NSC's main crane system (MCS), which includes the crane north maintenance garage area, was damaged by the drone strike and is currently not operational. The MCS is one of the building's main systems. The crane maintenance garage area houses several electrical cabinets for various systems, most of which were affected by the drone incident and by the water used to put out the resulting fires.
The NSC's other systems - providing relevant safety functions such as radiation monitoring, seismic monitoring, decontamination and radioactive waste management, power supply, and fire protection - remain functional, the IAEA team was informed.
While the heating, ventilation, and air conditioning systems remain functional, they are not in service after the drone incident, the Chornobyl site added.
"We are gradually getting a more complete picture of the severe damage caused by the drone strike. It will take both considerable time and money to repair all of it," Director General Grossi said.
On a more re-assuring note, there still has been no increase in radiation levels measured at the Chornobyl site, indicating there was no release of radioactive materials as a result of the strike.
At Ukraine's three operating nuclear power plants (NPPs) - Khmelnytskyy, Rivne and South Ukraine - five out of their total of nine units are currently operating and generating electricity. The four other reactors are in various stages of shutdown for planned maintenance and refueling, of which two are expected to restart soon.
The IAEA teams based at the three operating NPPs and the Chornobyl site have continued to report about air raid alarms on most days over the past week. The team at the Khmelnytskyy NPP had to shelter on the site in the morning of 30 April.
As part of the IAEA's assistance programme to support nuclear safety and security in Ukraine, the Khmelnytskyy NPP and Energoatom's Centralized Spent Fuel Storage Facility received radio-communication systems, procured with funding from the European Union. In addition, USIE Izotop - a Ukrainian state enterprise involved in the management of radioactive material intended for medical, industrial and other purposes - received software for dose assessments and related calculations, funded by New Zealand. This brings the total number of deliveries to 135 since the start of the conflict.
