On 21-27 October 2024, a team of experts from the International Atomic Energy Agency continued the work started in September to assess the condition of energy infrastructure facilities important for the safe operation of Ukrainian NPPs. The expanded monitoring mission at the power substations was carried out as part of the practical implementation of the agreements reached during the meeting of IAEA Director General Rafael Mariano Grossi with President of Ukraine Volodymyr Zelenskyy on 3 September 2024 in Kyiv and in accordance with the request of the Government of Ukraine.

Last week, the IAEA experts, together with experts from NPC «Ukrenergo», SE «NNEGC «Energoatom» and the SNRIU, visited the power substations identified by the Ministry of Energy of Ukraine as priority ones and reviewed the operational consequences of actual damage to the energy infrastructure that delivers power from nuclear power plants to consumers and ensures power supply for the power units' own needs.

As part of the mission, the IAEA experts assessed and documented:

• damage to electrical substations caused by missile and combined attacks by the russian federation;
• the results of the restoration work carried out to date and plans for the restoration and modernisation of substations in the future;
• the state of the capacity of electrical substations in their current configuration.

In addition, the IAEA experts had the opportunity to communicate with the managers and staff of the substations, Khmelnytskyy and South Ukraine NPPs, representatives of the SE «NNEGC «Energoatom» Directorate and discuss issues related to:

• interaction between power grid operators and NPPs in response to external influences;
• application of measures to ensure the reliability of external power supply to plants during transient processes in the grid;
• implementation of additional actions to improve NPP safety and security of electrical substations;
• expanding cooperation and potential capabilities of the IAEA to support nuclear safety, security and prevention of nuclear accidents in the context of a full-scale war unleashed by the russian federation against Ukraine.

It should be stressed that a reliable external power supply is crucial for the operation of nuclear power plants. The failure of electrical substation equipment poses significant challenges to NPP safety due to rapid transients characterised by sudden severe fluctuations in the power grid, which require operators to respond immediately and may lead to negative consequences for nuclear and radiation safety.

These understandable axioms are well known to the leadership of the aggressor country, which imitates its commitment to nuclear safety principles when promoting projects for the construction of new NPPs around the world, but conceals the facts of a significant increase in the cost and even the impossibility of successful implementation of such projects without stable operation of the relevant power systems.

Given Ukraine's experience, member states planning to develop their nuclear programmes in cooperation with russia should take into account that the protection of energy infrastructure elements in the event of hostilities requires significant financial and technical resources, which significantly increases the cost of building new facilities and does not guarantee their proper stability if the designer and general designer is an aggressor country that knows in advance the vulnerabilities of the facilities and ways to disable them.

“The russian federation irresponsibly directs various means of destruction at open switchgear, transformers, control panels, relay devices and substation backup power supplies, which increases the criticality of the Ukrainian power system, creates risks of accidents at NPPs, and is a deliberate crime of the nuclear power, which can be stopped only by joint efforts of the IAEA and its member states”, Head of SNRIU - Chief State Inspector for Nuclear and Radiation Safety of Ukraine Oleh Korikov said.

He added that the Government of Ukraine, the Ministry of Energy, the nuclear and radiation safety regulator, power system operators and NPPs are working to continue and expand the format of cooperation with the IAEA based on international safety standards, technical potential and political capabilities of the Agency to ensure nuclear safety and security of NPPs in the conditions of military aggression and at the recovery stage.

For reference:

At a special meeting of the IAEA’s Board of Governors on 2 March 2022, the IAEA Director General identified seven safety pillars that must be ensured under all conditions and stressed the need for a reliable and stable power supply for NPP safety (Pillar 4).

The availability of a reliable and stable power supply is also prescribed by IAEA Specific Safety Requirements SSR-2/1 (Rev. 1) “Safety of Nuclear Power Plants: Design” Requirement 41, and in more details described in IAEA Specific Safety Guide SSG-34 Design of Electrical Power Systems for Nuclear Power Plants and IAEA-TECDOC-1770 Design Provisions for Withstanding Station Blackout at Nuclear Power Plants.

According to the IAEA Report by the Director General on The Fukushima Daiichi Accident: The earthquake on 11 March 2011 caused major damage to the infrastructure in the region, including the loss of connections from the off-site power grid to the Fukushima Daiichi NPP. This resulted in a deviation from the normal operation of the plant (defence in depth Level 1).

According to the IAEA INSAG-10 Defence in Depth in Nuclear Safety, the ancillary and support systems such as electrical sources, are recognized as safety related and are subjected to appropriate surveillance.