Ukraine’s Zaporizhzhya Nuclear Power Plant (ZNPP) has started pumping water from a new groundwater well and plans to build more at the site in the coming month as part of efforts to ensure sufficient cooling for its six reactors after the destruction of the Kakhovka dam earlier this summer, Director General Rafael Mariano Grossi said today.
The collapse of the downstream dam on 6 June and the subsequent disappearance of much of the water in the Kakhovka reservoir, which the ZNPP had been using for its cooling needs, forced Europe’s largest nuclear power plant (NPP) to take steps to protect the bodies of water still available to it – including a large cooling pond next to the site – and to start looking for alternative sources of water.
The IAEA team of experts at the site has been informed that the new well, whose location close to the plant’s sprinkler ponds was selected after consultations with geological specialists, has already been commissioned and is now providing about 20 m3 of water per hour. The ZNPP intends to build an additional 10-12 wells around the perimeter of the sprinkler ponds.
At the same time, the site’s large cooling pond and its other main supply of water – the discharge channel of the nearby Zaporizhzhya Thermal Power Plant (ZTPP) – remain intact, the IAEA experts said. The height of the ZNPP cooling pond continues to drop by about 1 centimetre per day while water from the ZTPP inlet channel is regularly pumped into its discharge channel to compensate for water used for cooling or lost through natural evaporation. The site has sufficient cooling water for many months.
“The plant continues to take action to address the additional challenges caused by the loss of the Kakhovka dam some ten weeks ago. The fact that more wells will be built should add to the water reserves available for cooling. However, the overall nuclear safety and security situation remains precarious,” Director General Grossi said.
Underlining the potential risks for the plant located on the frontline of the conflict, the IAEA team continues to report about regular indications of military activity in the area, sometimes close to the site, sometimes further away. For example, a strong detonation shook their room windows on 14 August and gunfire was heard two days later. Another explosion near the site occurred on 17 August, five detonations were heard some distance from the ZNPP on 20 August and five more on 21 August.
“In order to prevent a nuclear accident that could affect people and the environment, it continues to be of paramount importance that the five basic principles for the protection of the Zaporizhzhya Nuclear Power Plant are respected and adhered to,” Director General Grossi said.
As part of their monitoring activities at the ZNPP, the IAEA experts are expecting access to the rooftops of reactor buildings 1, 2, 5 and 6 in the coming days. Earlier in August, the team did not observe any mines or explosives on the rooftops or turbine halls of units 3 and 4 after receiving the requested access there.
The IAEA team also continues to conduct regular walkdowns across the site. Over the past ten days, for example, the experts have visited: the cooling pond and cooling towers; the plant perimeter and sprinkler ponds; the main control room, emergency control room and other safety-related rooms of unit 3; the reactor hall, main pumps, steam generators, and safety system rooms of units 3 and 4; the reactor hall, main pumps, steam generators, and safety system rooms of unit 6; the turbine halls of units 3, 4, 5 and 6. In addition, on 14 August, the IAEA team went to the second of the plant’s fresh fuel storage facilities, where they confirmed that the fresh fuel was safely and securely stored. The IAEA experts did not observe any explosives and confirmed that the previously reported landmines remain in the same location in between the perimeter fences.
Reactor unit 6 has been generating steam for various nuclear safety purposes at the plant – including the processing of liquid radioactive waste – since 13 August when it reached a hot shutdown state, replacing the steam previously produced by unit 4. As reported by the IAEA on 10 August, the ZNPP began transferring reactor unit 4 from hot shutdown to cold shutdown following detection of a water leak at one of its four steam generators. There was no radioactivity released to the environment arising from the water leak at the steam generator in unit 4.
The cause of the leak, as later confirmed by the site, was due to a hairline crack in the weld of the steam generator primary header vent pipe. Last week, the site performed welding on the pipe and pressure testing of the steam generator was subsequently conducted, the IAEA team was informed. Final tests involving the primary and secondary circuits are in progress.
The IAEA continues to strongly encourage the installation of an external source of process steam, which, from a nuclear safety perspective, would provide the safest longer-term solution at the site. The IAEA has offered its assistance with this issue. In a possible step in this direction, the IAEA team was informed that the ZNPP has initiated a process to buy an external steam generator by sending technical requirements to possible vendors.
Separately, the IAEA is aware of reports of an explosion, with some injuries, on the morning of 18 August in the nearby city of Enerhodar, where most of the ZNPP’s staff live. The IAEA experts have not heard of any injuries to plant personnel and there was no damage reported at the ZNPP site.
In northern Ukraine, there were reports of a missile attack at the city of Chernihiv on the morning of 19 August with several fatalities and many injuries. The city is located around 40 kilometres from Slavutych where most of the Chornobyl site’s workers live. However, some of them live in Chernihiv itself. The IAEA experts have not heard of any injuries to plant personnel and there was no damage at the Chornobyl site. However, the IAEA team at the Chornobyl was informed that staff were very concerned about family and friends living in the affected area.
Director General Grossi expressed concern as such incidents could affect one of the seven indispensable pillars of nuclear safety and security that he outlined early during the conflict in Ukraine.
“The third pillar states that operating staff must be able to fulfil their safety and security duties and have the capacity to make decisions free of undue pressure,” he said. “It is not just damage to physical structures that puts Ukraine’s nuclear facilities at risk, but also the psychological impact on operating staff. That is why, as this terrible war continues, the Agency is working with Ukraine to provide medical assistance to Ukraine at, and in the vicinity of, nuclear facilities - including counselling services. This is vital work. But the real solution is for the conflict to end.”
In addition to their presence at the ZNPP and the Chornobyl site, IAEA experts maintain a continued presence at Ukraine’s other NPPs. Over the past week, the IAEA conducted rotations of its teams at Rivne, Khmelnitsky, and South Ukraine NPPs and will conduct a rotation at the Chornobyl site this week.