International Atomic Energy Agency (IAEA) experts have in recent days continued to inspect parts of Ukraine’s Zaporizhia NPP (ZNPP), without seeing any mines or explosives. They are still waiting to gain the necessary access to the rooftops of reactor units 3 & 4 following recent reports that explosives may have been placed there, Director General Rafael Mariano Grossi said, adding that the nuclear safety and security situation remains very precarious.

The five basic principles established by Grossi in May at the United Nations Security Council state that there should be no attack from or against the plant and that it should not be used as storage or a base for heavy weapons – multiple rocket launchers, artillery systems and munitions, and tanks. In recent days, the IAEA experts have heard a series of explosions apparently taking place some distance away from the ZNPP but still a stark reminder of potential nuclear safety and security risks facing the facility during the military conflict in the country.

Since Russia took control of ZNPP in March 2022 as part of its special military operation in Ukraine, the Russian national guard, Rosgvardiya, has been protecting the station. In October 2022, Russian President Vladimir Putin signed a decree formally transferring ZNPP to Russian jurisdiction under nuclear utility Rosenergoatom (part of Rosatom). A Russian Federal State Unitary Enterprise. Zaporizhia NPP was established by Rosenergoatom to operate the plant. However, Ukrainian nuclear utility Energoatom still claims ownership of the plant.

Reports by Russian military have in recent months suggested that retaking control of ZNPP is one of the main objectives of the Ukrainian counter-offensive. There have been four unsuccessful attempts by Ukrainian forces to storm the plant since September 2022. However, that risk now seems to have abated. Russia and Ukraine have blamed each other for shelling that has repeatedly downed power lines vital to cooling the reactors, which are shut down but which need a constant supply of electricity to keep the nuclear fuel inside cool and prevent a possible meltdown. Russia and Ukraine also accused each other of destroying the Nova Kakhovka dam, drastically reducing levels in the Kakhovka reservoir, which provides cooling water for the plant.

IAEA said one blast occurred in the morning of 8 July, several in the evening of 10 July, one on 11 July morning and five in the evening. While it was not possible to determine the exact locations of the explosions, the IAEA experts were able to confirm that the site had not been impacted.

On 9 July, the IAEA team went to areas just inside the site perimeter and around the sprinkler cooling ponds. On 10 July, the experts went to the main control room, emergency control room, rooms where electrical cabinets of the safety systems are located and to the turbine hall of reactor unit 1, and on 12 July they visited the corresponding areas in unit 3. On 11 July the team also visited the unit 1 reactor hall, coolant pumps and safety system pumps. The experts reported that they had unrestricted access to these areas.

The IAEA continues to closely follow developments related to the availability of water for cooling the ZNPP’s six reactors and other essential nuclear safety and security functions, following the destruction of the downstream Kakhovka dam in early June and the subsequent depletion of the huge reservoir near the plant.

The IAEA team said the two main bodies of water – the ZNPP’s cooling pond and the discharge channel of the nearby Zaporizhzhya Thermal Power Plant (ZTPP) – had been relatively stable, with the water level decreasing by 1-2 centimetres per day due to usage and evaporation. The site continues to have sufficient water for some months.

As part of ongoing efforts to explore back-up options, the plant is planning to construct additional wells that could be used to replenish essential cooling water for the sprinkler ponds, which are currently utilizing underground water pumped from the site’s drainage system.

During the past week, a submersible pump was used to transfer some of the residual water in the ZTPP inlet channel into the ZTPP discharge channel, slightly increasing the height of the water in this channel.

The plant is separately preparing to move reactor unit 4 from cold shutdown to hot shutdown – after which unit 5, currently in hot shutdown, will be placed in cold shutdown in order to carry out preventive maintenance activities that are only possible in cold shutdown. The other units remain in cold shutdown.

The site uses the steam generated from one reactor unit in hot shutdown for various nuclear safety purposes including the processing of liquid radioactive waste collected in storage tanks. However, the IAEA experts are strongly encouraging the ZNPP to investigate all possible options to install an external boiler to generate the steam required, which would enable the site to bring all units into a cold shutdown state. The Ukraine national regulator – SNRIU – has issued regulatory orders to limit the operation of all six units to a cold shutdown state.

IAEA said it is continuing to ask ZNPP to improve the conditions on site for Agency staff, including better accommodation, living and working conditions.

The previous week, ZNPP was visited by Sergey Kirienko, First Deputy of the Russian Presidential Administration and Chairman of Rosatom’s Supervisory Board, and Yevgeny Balitsky the [Russian appointed] Governor of the Zaporozhye region. They investigated the site of the dry storage for used nuclear fuel and verified its safety. Balitsky noted that safety had been strengthened with an additional protective wall and a layer of concrete.

ZNPP said the design of this storage facility includes ventilated concrete containers for storing used fuel assemblies in a vertical position. The storage area is an open area designed for the safe storage of containers for at least 50 years. The storage is designed for 380 containers with containing more than 9,000 assemblies with used nuclear fuel. The system is passive and does not require significant maintenance.

Each container consists of two components – an internal multi-seat sealed basket, and an external concrete container and made of high-strength materials. The containers are constantly monitored.

All work at the storage site is carried out under the constant supervision of the IAEA mission.

Meanwhile, Ria Novosti and Tass reported conversation with the director of the Russian Foreign Intelligence Service (SVR), Sergey Naryshkin. He told them that the SVR is permanently monitoring the situation at ZNPP and constantly receives data on the situation at the plant. Naryshkin added that he had held an hour-long telephone conversation with William Burns, the head of the US CIA, at the end of June,. They had discussed the situation in Ukraine and "thought about what to do with it”. It seems this may have been a factor which contributed to averting the anticipated attack on the NPP.

As to the other NPPs in Ukraine, IAEA said that, since January this year, the IAEA also has a permanent presence at Ukraine’s other nuclear power plants – the Khmelnitsky (KhNPP), Rivne (RNPP), South Ukraine (SUNPP) and the Chornobyl (ChNPP) sites – where the most recent rotations of experts took place last week.

The IAEA teams report that the sites are continuing to maintain their operating and refuelling schedules despite the challenges faced by the conflict. They also confirm that there are no nuclear safety or security related issues at the four sites. Among other activities, these IAEA experts help facilitate the delivery of assistance to Ukraine’s NPPs, organised by IAEA staff in Vienna, by discussing the technical specifications of safety and security equipment requested with their counterparts at the sites.

In the last two weeks, two deliveries of equipment to Ukraine took place, bringing the total to 21 since the conflict began in February 2022. With the most recent deliveries, the KhNPP, SUNPP and RNPP received medical equipment and supplies that are essential for providing medical care and support, both to Ukrainian operating staff as well as to IAEA personnel at the sites.

In addition, the RNPP, SNRIU and State Enterprise Eastern Mining and Processing Plant, SE VostokGOK, received IT equipment, power supply systems, infrared sensors and portable tritium detectors. This equipment was procured with funds provided by Australia, the Republic of Korea and the USA as well as with support of the European Union.