"The State Nuclear Regulatory Inspectorate of Ukraine said technicians in the Zaporozhye facility, about 342 miles southeast of Kyiv, were still at work, and local authorities confirmed that the fire was extinguished around 6:20 a.m. local time.

The International Atomic Energy Agency (IAEA) said the fire had not affected essential equipment and that Ukraine’s regulator reported no change in surrounding radiation levels. U.S. Energy Secretary Jennifer Granholm tweetedthat the Energy Department has also seen no elevated radiation readings.

'The plant’s reactors are protected by robust containment structures, and the reactors are being safely shut down,' Granholm said.

Ukrainian officials immediately raised the possibility of another disaster echoing the deadly 1986 catastrophe at the Chernobyl nuclear plant in northern Ukraine Ukrainian President Volodymyr Zelensky warned in a video message that an explosion at the six-reactor, 5,700-megawatt Zaporozhye plant could spell the “end of Europe.” 

Just a bit of hyperbole as this could not possibly happen, since Chernobyl itself didn’t do that much damage (see below) and the reactors are about as different as they could be. Chernobyl was an RBMK dual-purpose weapons reactor with no containment structure, with graphite as its moderator, and operated with a positive void coefficient, the combination of which, together with human stupidity and hubris, cause the meltdown and explosion. It was designed to make a lot of plutonium for weapons, thus the graphite."