That plant is a PWR, the water/steam in the turbine loop never contacts the fun stuff in the reactor core, there's a heat exchanger in between.
Hydrogen cooled turbogenerators are a thing, although I don't know if this plant used them, probably did. Nice and cool, high efficiency. The press release claims an alternator cooling fan overheated or whatever and that caused symptoms that sound like a hydrogen cooled turbogenerator having a nice leak and subsequent fire. Doesn't mention a steam leak. So that's like one more heat exchanger away from the fun stuff.
Explosions and fires and fire fighting can cause disruption and raise dust in theory, but the isotope detected has a very short half life so this wasn't a leak from a decade ago getting washed into the environment by a fire hose.
This incident was not located in a nuclear area and it hasn't been classified as a nuclear incident. Can't be responsible for iodine emission in the atmosphere.
