The Zaporozhye Nuclear Power Plant (ZNPP) sits at the edge of the giant reservoir kept full by the Novo Khakovka Dam. When that Dam was blown up three days ago, water levels in the Reservoir began to plummet. This is causing water in the cooling pond that feeds water to the ZNPP to plummet as well.
The graphic below shows the impact of the receding water level at the plant and it's cooling pool:
Without sufficient cooling water, the nuclear reactors at the ZNPP will not be cooled, resulting in a nuclear disaster.
This is like a ticking time bomb. No one knows how long water levels will remain high enough to provide cooling water to the reactors. Disaster could be just DAYS away.