Today the Nova Kakhovka dam was severely damaged leading to a significant reduction in the level of the reservoir used to supply cooling water to the ZNPP.
The water is required for the essential cooling water system which provides cooling (among other) to the following:
- residual heat removal from the reactors (spent or partially spent fuel there);
- residual heat removal from the spent fuel ponds; and
- cooling of the emergency diesel generators (when they are running).
Absence of cooling water in the essential cooling water systems for an extended period of time would cause fuel melt and inoperability of the emergency diesel generators.
However, our current assessment is that there is no immediate risk to the safety of the plant.
The IAEA staff on the site have been informed that the damage to the Nova Kakhovka dam is currently leading to about 5 cm/hour reduction in the height of the reservoir. The team continues to monitor this rate and all other matters on the site.
The main line of cooling water is fed from the reservoir and pumped up through channels near the thermal power plant to the site. It is estimated that the water through this route should last for a few days.
Water in the reservoir was at around 16.4 m at 8 am. If drops below 12.7 m then it can no longer be pumped.
ISAMZ reported that ZNPP is making all efforts to pump as much water into its cooling channels and related systems as possible. In addition, non-essential consumers of water are being stopped at ZNPP to reduce the consumption of water.
ZNPP management is discussing further measures to be implemented.
There are a number of alternative sources of water.
A main one is the large cooling pond next to the site that by design is kept above the height of the reservoir. As the reactors have been shut down for many months it is estimated that this pond will be sufficient to provide water for cooling for some months. The Agency will confirm this very shortly.
It is therefore vital that this cooling pond remains intact. Nothing must be done to potentially undermine its integrity.
I call on all sides to ensure nothing is done to undermine that.
My trip to ZNPP next week was planned and now it is essential. I will go.
I will keep the Board informed as developments unfold.