International Atomic Energy Agency (IAEA) experts have carried out additional inspections and walkdowns at Ukraine's Zaporizhzhya Nuclear Power Plant (ZNPP) over the past week - so far without observing any heavy military equipment, explosives or mines - but they are still awaiting access to the rooftops of the reactor buildings, Director General Rafael Mariano Grossi said today.
Following their visits to units 1 and 3 earlier in July, the IAEA experts went to the reactor building of unit 2 on 17 July and unit 4 the following day. In each case, the team checked the main control room, reactor hall, spent fuel pool, emergency control room, rooms where electrical cabinets of the safety systems are located, and the turbine hall.
While the IAEA experts saw transport trucks in the turbine halls of units 1, 2, and 4, there was no visible indication of explosives or mines. The team has not yet been granted requested access to the roofs of the reactors and their turbine halls, including units 3 and 4 which are of particular interest. The Agency continues to request such access.
The five basic principles that Director General Grossi established on 30 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.
The IAEA team did not report hearing any explosions over the past week, in contrast to the preceding week when it was almost a daily occurrence, underlining the volatile security situation in the region located on the frontline of the conflict.
The IAEA experts are continuing to closely monitor the situation regarding 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 reported that the available water supply remains relatively stable, with the water level decreasing by around 1 centimetre per day due to usage and evaporation. The site continues to have sufficient water for some months.
On 13 July, the experts went to the site's large cooling pond - one of the main bodies of water still available for the plant's cooling needs - and confirmed the integrity of its isolation gate and the absence of leaks. They also observed the plant's work to further strengthen the isolation gate by placing additional reinforcement barriers on the outer side.
Over the past week, the team has also been at the site's other main body of available water - the discharge channel of the Zaporizhzhya Thermal Power Plant (ZTPP) - and also there confirmed the integrity of its isolation gate and witnessed ongoing activities to strengthen the walls of the smaller channel transferring water from the discharge channel to the cooling pond.
Since the destruction of the dam some six weeks ago, the ZNPP has been relying on water from the site's cooling pond, the ZTPP discharge channel and underground water from the drainage system for its needs. The plant is still making efforts, using submersible pumps, to obtain additional water for the ZNPP from the ZTPP inlet channel, which used to be fed by the Kakhovka reservoir. However, the remaining water in this channel appears to be limited to the ingress of groundwater.
In addition, water from existing wells can be used to replenish the site's smaller sprinkler ponds. The IAEA team was informed that drilling of a test hole had been conducted at a location outside the site perimeter as part of work to find a suitable spot to build another well as an alternative source of water. The plant is now testing the quantity and quality of the water to determine the location is suitable.
"Since the Kakhovka dam was destroyed - leading to the disappearance of the huge reservoir as a reliable source of water - the Zaporizhzhya Nuclear Power Plant has been conducting a range of activities to both secure the remaining bodies of water and find new ones," said Director General Grossi.
The plant is separately continuing its preparations to move reactor unit 4 from cold shutdown to hot shutdown, informing the IAEA experts that all scheduled tests on this unit were successfully completed prior to commencing the transition. Once that is done, reactor unit 5 - now 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 have been encouraging the ZNPP to investigate 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.
With respect to external electricity supplies - needed to pump the cooling water and for other essential nuclear safety and security functions - the ZNPP continues to have access to one main 750 kilovolt (kV) off-site power line as well as one 330 kV line used for back-up supplies. That, however, is not sufficient for sustainable safe operations, Director General Grossi said, noting that the site had access to four 750 kV power lines before the conflict.
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. The IAEA teams report that the sites are continuing to maintain their operating and refuelling schedules despite the challenges. They also confirm that there are no nuclear safety or security related issues at the four sites. The IAEA carried out a rotation of staff at Chornobyl this week, and rotations at the other sites will take place soon.
Next week, the IAEA will send a fact-finding mission to Kyiv and Kharkiv as part of activities to assist Ukraine in ensuring the safety and security of radioactive sources, which are commonly used in a wide range of peaceful activities, for example in hospitals and industry.
"The IAEA Support and Assistance Mission on the Safety and Security of Radioactive Sources in Ukraine - ISAMRAD - will assess the radiation safety and nuclear security situation regarding radioactive sources in the country and also identify equipment and other requirements. This is another important area of assistance provided by the IAEA at the request of Ukraine," Director General Grossi said.
