[pcm81]

Here is the google mapm link to the power plant. Looks like it has 6 reactors.
https://www.google.com/maps/@47.5150482,34.6012032,911a,35y,250.65h,44.67t/data=!3m1!1e3!5m1!1e4
Here is an MSNBC video to get you caught up on the news: https://www.youtube.com/watch?v=zZO2x2o-rHg

Can't find exact match of the building from the video that is on fire. Closest thing i can find is this angle: https://www.google.com/maps/@47.5138694,34.5943625,3a,60y,221.54h,91.12t/data=!3m6!1e1!3m4!1s5T_IedBxGUuT0mbm0luFJw!2e0!7i13312!8i6656!5m1!1e4

[chworld]

It's good that everything worked out, at the moment there is no reason to worry. The Zaporizhzhia Nuclear Power Station is the largest nuclear power plant in Europe and among the 10 largest in the world.

[Enthalpy]

Again fights at Zaporizhzhia yesterday, including shelling and some damage. One reactor shut off automatically, the others run still.

Some days ago, the Russian army installed weapons at the nuclear power plant, supposedly to fire from them without being shelled.

[Enthalpy]

"Experts" downplayed in several newspapers last week the pollution risk by shelling the nuclear power plant. Example:
  20minutes.fr
claiming that the confinement resists shelling.

The dry storage of spent fuel is outside the reactor building and resists no shell
  uatom.org
If it's hit, the radioactivity is released. After the initial storage in the spent fuel pools, radioiodine has decayed, but radiocaesium, radiostrontium and others persist.

The VVER-1000 reactors have 1.1m concrete at the dome, as resistant as 25cm steel. Just the flechettes and the shaped charged fired by the old T-72 battletank pierce 25-45cm steel, and that's no big weapon. Already WWII howitzers could pierce 3.5m concrete.

[Enthalpy]

Despite the war in Ukraine demonstrates the hideous danger of nuclear power plants, the Japanese and British prime ministers, and now the French president, tell "we need new nuclear power plants". Does the need for tritium, an ingredient of nuclear bombs, explain rationally this apparent foolish?

I say no. Cyclotrons can provide enough tritium to maintain France's or Britain's nuclear bombs. They are cheaper than nuclear power plants and not vulnerable. Both countries have more than enough plutonium, which doesn't disappear in a lifetime.

Tritium and deuterium make the booster of plutonium bombs (or of primaries in a multistage bomb). Each bomb is said to contain 2.5g tritium, according to
  nuke.fas.org - nuclearweaponarchive.org
which decays by 5.5%/year due to radioactivity and must be replenished.

France has 300 bombs if believing then-president François Hollande, Britain is said to be in the same ballpark. Maintenance needs 42g/year = 14mol/year.

I estimated that a 200MeV cyclotron of moderate size produces 1mol/year neutrons, which lithium converts to tritium
  chemicalforums
so just 14 cyclotrons suffice, or even five 500MeV cyclotrons.

They produce far less radioactivity, so a direct hit leaves the country habitable. They need little cooling and can be buried. Their loss has no swift consequence so they are no targets. Several sites can host them.

Or could just deuterium make the booster, without tritium? I don't know. After I suggested it, Pres. Trump considered conducting new tests of nuclear bombs.

[Enthalpy]

[...] The dry storage of spent fuel is outside the reactor building and resists no shell
  uatom.org
If it's hit, the radioactivity is released. [...]

Keep some hope. Rosenergoatom finishes "additional protection" for Zaporizhzhya's spent fuel
  n-tv.de search for 10:22

The VVER-1000 reactors have 1.1m concrete at the dome, as resistant as 25cm steel. Just the flechettes and the shaped charges fired by the old T-72 battletank pierce 25-45cm steel, and that's no big weapon. Already WWII howitzers could pierce 3.5m concrete.

But no hope exists to protect against serious munition. In a conflict, nuclear power plants are sitting ducks waiting to make a province uninhabitable like Chernobyl did.

[Enthalpy]

The Zaporizhzhja nuclear power plant lost its only operating high voltage line in a missile attack yesterday. Already repaired, but this time the reactors 5 and 6 were in operation. As IAEA's Rafael Grossi told: it's the sixth time, one day our luck will run out.
  aljazeera

==========

Without the power line, the alternators have no electric load, they don't brake the turbines, all accelerate. A typical speed safety factor is only 1.2× before turbines break. Such machines are about 40m long, and they leave little time to react.

That accident wouldn't be nuclear... except if the spinning rotor of a turbine or alternator punches through the stator and accelerates on the ground, which did happen with series-connected electric motors. At older French nuclear power plants, some rotors would accelerate towards the next reactor.

==========

As the turbines stop and absorb no more heat power, so must the reactors, and quickly. Problem: the radioactivity still produces some 10% (100MW!) of the fission power, and at the VVER-1000 and most designs it must be evacuated actively with pumps.

Future concepts seek passive removal of the radioactivity heat by natural convection, or a small engine that converts this heat into enough power for the pumps. Others would offer enough capacity to absorb this heat. Very few operating power plants have such features.

That's why a nuclear reactor needs power after shutdown. They aren't safer when unplugged. At Zaporizhzhja the Diesel generators have started every time. At Fukushima they didn't.

Without cooling power, the pressure vessel would vent the vapor or burst. Unlike Chernobyl, the VVER-1000 at Zaporizhzhja have a confinement dome. Alas, it resists only if helped by sprinklers that condensate the vapor if they have power.
  irsn.fr - de.wikipedia
That's more or less what failed at Fukushima.

[wildfyr]

I cannot believe how the Russians gamble with this plant. How are they not equally terrified of a meltdown?

[Enthalpy]

Err, I have no excellent reason to suspect one side rather than the other... In this case, the power line was damaged. Earlier, the NPP itself was bombed, when Russian soldiers occupied it.

I didn't find in the Press where Zaporijja's electricity goes. Over the Ukrainian network yes, but to Kiev or to Crimea? Since the Russians operate the NPP and let two reactors run while they try to destroy the Ukrainian electricity network, it's conceivable that the electricity goes to Crimea.

Terrifying, yes. But not more than the ongoing war, which kills more people than a meltdown and lets abandon vast territories too. And, well, some people may gamble that the redundant Diesels will start.

[wildfyr]

It is generally clear that the Ukranians have taken pains to try to avoid damaging the plant, and Russians have used it as a shield from which to stage attacks and shoot artillery, at best.

The single power line, who knows.

[Enthalpy]

For some years I keep writing things like: don't build any because nuclear power plants are targets for ballistic missiles, a hit lets them release the radioactivity as in Chernobyl, and for instance Iran can build such missiles.

Here we are, Iran claims to have a hypersonic glider, a technology younger than ballistic missiles.
  aljazeera
Less detectable and more agile than a ballistic missile, not as fast at the impact but it would burst through all concrete and metal at a nuclear power plant. The range is a mere matter of tinkering.

To the very least, all fast neutron reactors should be stopped, because a hypersonic impact puts them more likely into prompt criticality and they contain 100t plutonium, not 5kg like a bomb. PhD Angela Merkel stopped all German fast neutron reactors after I wrote that, maybe some study report still exists at the Government?