"Unprecedented": IAEA head on the current threat of nuclear catastrophe in Ukraine

Europe's biggest nuclear power plant, Zaporizhzhia, is maybe the most dangerous place in the world right now. The plant is in Russian-occupied Ukraine and has been shelled repeatedly since March. The situation is carefully monitored by the International Atomic Energy Agency, the U.N.'s nuclear watchdog agency tasked with making sure nuclear facilities are safe and atomic material is only used for peaceful purposes. Its director general, Rafael Mariano Grossi, recently inspected the site. "Well, it's an unprecedented thing, really, in so many ways," Grossi told Lesley Stahl for this week's 60 Minutes. "This place is at the front line which makes the whole thing so volatile and in need of an urgent action." Before the war the plant supplied 20% of Ukraine's power. It's now largely idle, but the reactors still need to be constantly cooled down with circulating water. If they over-heat it could lead to nuclear catastrophe within hours. "The whole system is being cooled by electricity that'