UN agency warns of ‘discrepancy’ between measurements, but confirms plant safety
An International Atomic Energy Agency (IAEA) expert team should be allowed access to the Russia-occupied Zaporizhzhia nuclear power plant in Ukraine to examine “discrepancies” between measurements of the height of the reservoir that is supplying water to cool the facility’s six reactors and spent fuel storage, said the UN body’s head Rafael Grossi.
Grossi said in a statement that the level of the Kakhovka reservoir has been dropping rapidly since an explosion breached its dam wall on Tuesday last week, but measurements at the local inlet and pond at the Zaporizhzhia plant have remained stable.
According to the IAEA, the plant canal inlet levels have been recorded at 11.27 metres on Sunday, down from nearly 17 metres before the dam collapse. However, the agency said, global levels for the Kakhovka reservoir have continued to decrease, while the Zaporizhzhia readings have remained unchaged, providing for a discrepancy of about two metres.
“It is possible that this discrepancy in the measured levels is caused by an isolated body of water separated from the larger body of the reservoir. But we will only be able to know when we gain access to the thermal power plant,” Grossi said.
The IAEA confirmed that the current height of the Kakhovka reservoir near the Zaporizhzhia plant is enough to keep inlet water pumps operable, but said these have not been in active use since the local pond at the plant holds sufficient water for the facility’s cooling requirements, including reactor and spent fuel cooling.
Currently, five of the six reactor units at Zaporizhzhia are in confirmed cold shutdown, which is the safest of reactor states requiring minimal cooling. On 8 June, Ukraine’s nuclear regulator said Unit 5 should be the last reactor to be transferred to a cold state in the wake of the Kakhovka dam collapse. However, Russian operators are in full control of Zaporizhzhia-5 and its last know status has been that of a hot shutdown.
Last week, the IAEA said there was no immediate need for the six-unit facility, the largest nuclear power station in Europe, to switch to alternative water supplies including a large cooling pond next to the station and its smaller sprinkler cooling ponds, the adjacent channels, and onsite wells, which can provide required cooling water for Zaporizhzhia “for several months”.
“Nevertheless, the general nuclear safety and security situation remains very precarious and potentially dangerous,” said Grossi at the time.
Even though the facility’s six VVER-1000 pressurised water reactor units are all in shutdown mode, they still require cooling water to prevent fuel melt and a possible release of radioactive material, he said.
According to the latest statement by Ukraine’s nuclear power operator Energoatom, the water level of the Kakhaovka reservoir just outside of the Zaporizhzhia plant was 9.04 metres at 20:00 local time on Sunday, while the level at the local cooling pond was 16.67 metres.
Energoatom, which has not been in control of the Zaporizhzhia plant since Russian troops occupied it in early March 2022, said that reactor units at the site have not been operating since September 2022, and therefore active use of water from the cooling pond has not occurred since then.
The measured level of 16.67 metres is enough to meet Zaporizhzhia’s needs, Energoatom said.
Director-general Grossi is scheduled to visit Ukraine later today to speak to government officials and assess conditions after the Kakhovka dam collapse.
The article was updated on 13 June with new information on the status of the six Zaporizhzhia reactor units.
