EXPLAINER: How dangerous was Russia's nuclear plant strike?

Russian shelling of Europe’s largest nuclear power plant that sparked a fire at one of its six reactors has raised fears of a disaster that could affect all of central Europe for decades, like the 1986 Chernobyl meltdown

BANGKOK -- Europe's largest nuclear power plant was hit by Russian shelling early Friday, sparking a fire at one of its six reactors and raising fears of a disaster that could affect all of central Europe for decades, like the 1986 Chernobyl meltdown.

Concerns faded after Ukrainian authorities announced that the fire had been extinguished, and while there was damage to the reactor compartment, the safety of the unit was not affected.

But even though the Zaporizhzhia nuclear plant is of a different design than Chernobyl and is protected from fire, nuclear safety experts and the International Atomic Energy Agency warn that waging war in and around such facilities presents extreme risks.

One major concern, raised by Ukraine's state nuclear regulator, is that if fighting interrupts power supply to the nuclear plant, it would be forced to use less-reliable diesel generators to provide emergency power to operating cooling systems. A failure of those systems could lead to a disaster similar to that of Japan's Fukushima plant, when a massive earthquake and tsunami in 2011 destroyed cooling systems, triggering meltdowns in three reactors.