How safe is the release of Fukushima nuclear wastewater? The IAEA, and the governments of Japan and South Korea have declared the releases safe. People all around the Pacific Ocean are protesting the releases however. Where does the nuclear wastewater come from? What is in it?Because the melted nuclear cores (corium) of reactors 1, 2 & 3 at Fukushima Dai'ichi are somewhere underneath the three reactor buildings, having melted out, workers at TEPCO have been pouring cold water on the corium