In his latest update on the situation at the Zaporizhia Nuclear Power Plant (ZNPP), International Atomic Energy Agency (IAEA) Director General Rafael Mariano Grossi said the plant has begun pumping water from a new groundwater well. It also plans to build more at the site in the coming month as part of efforts to ensure sufficient cooling for the six reactors after the destruction of the Kakhovka dam in June.
The collapse of the downstream dam led to the disappearance of much of the water in the Kakhovka reservoir, which the ZNPP had been using for its cooling needs. This forced the plant to take steps to protect the bodies of water still available – including a large cooling pond next to the site – and to start looking for alternative sources.
The IAEA team of experts present at the site has been informed that the new well, located close to the plant’s sprinkler ponds, was selected after consultations with geological specialists. It has already been commissioned and is now providing about 20 cubic metres of water per hour. 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 Zaporizhia Thermal Power Plant (ZTPP) – remain intact. IAEA said the height of the ZNPP cooling pond continues to drop by about 1 centimetre a 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,” Grossi said.
Underlining the potential risks for the plant, which is 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 ZNPP on 20 August and five more on 21 August.
As part of their monitoring activities at the ZNPP, the IAEA experts are expecting access to the rooftops of reactor buildings 1, 2, 5&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&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.
Image: Zaporizhia nuclear units 1&2