Ukraine’s Zaporizhzhia Nuclear Power Plant (NPP) is continuing to pump cooling water from the Kakhovka reservoir, despite the water level reaching a point at which it was previously estimated that the pumps could no longer operate, Director General of the International Atomic Energy Agency (IAEA) Rafael Mariano Grossi said yesterday (8 June).
The reservoir’s water level has now dropped by around 4.1 metres since the downstream dam was breached early on Tuesday. On Thursday at 6 pm local time, it reached around 12.7 metres, the level at which it was previously estimated that the Zaporizhzhia NPP could no longer access this body of water for cooling the plant’s six reactors and spent fuel, after which the plant would use alternative water sources.
The hourly loss rate remains in the range of between four to seven centimetres per hour, Director General Grossi said, citing data from the IAEA team on the ground in Zaporizhzhia.
The IAEA experts were informed yesterday that the plant had assessed, following a review, that it should be able to pump water from the reservoir also after its level falls below 12.7 metres. Thus far, the results indicate that the pumps can likely still be operated even if the level drops to around 11 metres or possibly lower.
As the ZNPP receives water from the reservoir via the cooling system of the nearby Zaporizhzhia Thermal Power Plant (TPP), the review included interviews with retired ZTPP staff who have experience and expertise in the design of this facility’s cooling systems from the time that the ZTPP was built in the 1970s, prior to the construction of ZNPP in the 1980s.
“In these difficult and challenging circumstances, this is providing some more time before possibly switching to alternative water supplies including the large cooling pond next to the plant as well as its smaller sprinkler cooling ponds, the adjacent channels, and onsite wells, which can provide required cooling water for the Zaporizhzhia Nuclear Power Plant for several months,” Director General Grossi said. “Nevertheless, the general nuclear safety and security situation remains very precarious and potentially dangerous.”
The Director General stressed that the extent of the dam’s damage remained unknown, and it is also not clear when and at what level the reservoir will stabilise.
To better assess the situation, the IAEA experts have requested access to the location where the reservoir’s water level is measured and also to the ZTPP discharge channel adjoining the ZNPP. “It is essential that the ISAMZ team can independently verify the status of the systems that provide cooling water to ZNPP,” Director General Grossi said.