Reliable offsite power vital for maintenance and operation of safety functions, IAEA warns
Two Ukrainian nuclear power stations have been operating at reduced capacity for the past 10 days after a military attack damaged an electrical substation critical for nuclear safety and security, International Atomic Energy Agency (IAEA) director-general Rafael Grossi said on 17 November.
Substations are critical nodes in a country’s electrical grid, serving as facilities where voltage levels are transformed and controlled to ensure reliable power transmission.
The IAEA said that for nuclear power plants, they are indispensable for maintaining offsite power supplies that support safety systems and cooling functions, making their integrity vital for nuclear safety and security.
Following the latest military activity targeting a substation, during the night of 7 November, the Khmelnitski and Rivne nuclear stations were each disconnected from one of their two 750 kilovolt (kV) power lines. In addition, the grid operator ordered a reduction in electricity output of some of their reactors.
The IAEA said on Monday that although one of the affected lines has since been restored, the other remains out of service. Three reactors continue to operate at limited power, at the request of the grid operator.
According to the IAEA, Khmelnitski, in the west of the country, has two units in operations and two under construction. Rivne, in the north of the country about 100 km from the border with Belarus, has four units in operation,
“Reliable offsite power is vital for the maintenance and operation of nuclear safety functions,” Grossi said. “To this end, agency experts will, through dedicated expert missions, continue to assess the functionality of substations critical for nuclear safety and security.”
The Zaporizhzhia nuclear power station, which is near the frontline of fighting in southeast Ukraine and has been occupied by Russia since soon after its invasion in February 2022, remains connected to the grid after repairs carried out under the protection of IAEA-brokered localised ceasefires in late October and 10 days ago.
Ending a month-long outage of offsite power, this has allowed the resumption of maintenance of the plant’s safety systems.
However, one of the two offsite power lines that were re-connected thanks to the recent repairs – the 750 kilovolt (kV) Dniprovska line – was again disconnected on the evening of 14 November after the actuation of a protection system. The cause is still being investigated. The IAEA is engaging with both sides to assist in the timely restoration of the line, Grossi said.
IAEA’s ‘Comprehensive Programme Of Assistance’
The IAEA continues to implement its comprehensive programme of assistance to Ukraine in nuclear safety and security.
As part of the programme, the IAEA completed partial deliveries of items to the joint stock company Mykolaivoblenergo, which maintains substations, consisting of electrical cabinets, circuit breakers surge arresters and similar items needed to maintain a reliable power supply for the safe operation of Ukraine’s NPPs.
Additional items, that are still in production, will be delivered in the coming months.
In addition, the South Ukraine nuclear power station received 12 gamma dose rate monitoring stations intended to improve its radiation monitoring capability.
Ukraine’s Central Enterprise for the Management of Radioactive Waste received IT equipment and the Chernobyl nuclear power station received an off-road vehicle. Both deliveries were funded by the UK and aimed at increasing nuclear security measures at the two sites.
These deliveries brought the total organised during the conflict by the IAEA to 174, amounting to over €20.5m ($23.7m).
Cooling towers at the Rivne nuclear power station in northern Ulraine. Courtesy Wikipedia/Creative Common Licence.
