This is the third nuclear plant destroyed in a few weeks by a typhoon (after Brunswick in North Carolina and Sendai in Kyushu).
Here the proof is indirect as I could not follow through webcams the plant as I did in Satsumasendai (being able to record from the livestream the impressive light of the blast).
But there is a good level of evidence. I am assuming it happened in Kori and not Wolsong.
All the clocks are at my computer time (France).
1. Geiger spike matching the wind streams :
Korea depends on thermal for most of its electricity and it is EASY to start reserve thermal plants to conceal the loss of a nuclear plant. Compare the headlines :