Ukraine's nuclear plant has lost power supply: IAEA

BREAKING: Ukraine's nuclear plant has lost its external power supply, the IAEA says.

Ukraine's nuclear plant has lost its external power supply. That's from the IAEA, the UN's nuclear watchdog, and it's the kind of alert that makes everyone in Vienna sit up straight.

This is the plant we're talking about, the biggest nuclear station in Europe, sitting in a war zone. External power is what keeps the cooling systems running, and cooling is the whole game with a reactor. When the grid connection goes down, the plant falls back on emergency diesel generators, and generators are a stopgap, not a solution.

The agency, headquartered here in Vienna, has been warning about exactly this scenario since the early days of the war. Every time the lines get cut, the margin for error gets thinner.

No word yet on how long restoration will take. But a nuclear plant running on backup power in the middle of a war is not a situation anyone gets to relax about.

This is Liu Yang, reporting for HIT.