The head of the United Nations nuclear watchdog said on Thursday he worried the world was becoming complacent about the considerable dangers posed by the Russian-controlled Zaporizhzhia atomic plant in Ukraine. Russian forces captured the plant, Europe’s largest, in March and it has repeatedly come under fire in recent months, raising fears of a nuclear disaster. Rafael Grossi, director general of the International Atomic Energy Agency (IAEA), is working to set up a safe zone around the facility.