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.
"Iodine-131 is a radionuclide with a short half-life (T1/2 = 8.04 day)."
Short half life, a nuclear event of some sort happened recently and nothing has been reported. I-131 is an isotope of Iodine and the source could be natural gas related, medical diagnostic OR a product of uranium and plutonium used in nuclear fission. [0]
Which countries have access to plutonium?
"only particulate iodine was reported."
What is the source of the particles?
"first found during week 2 of January 2017 in northern Norway."
What countries have access to plutonium that are active near Norway?
Iodine has a short half-life (8 days) which is the time for half of the material to decay. This means that somewhere in europe, recently, someone is creating / releasing radioactive iodine. However, the levels are extremely low, so it isn't dangerous.
I guess something happened in the eastern part of Europe, possibly Ukraine, Belarus, Russia, Poland etc. The event was small, yet it was certainly nuclear due to a sudden increase of iodine, even if within range considered still healthy. Obviously nobody reported anything before it was picked up by detectors.
