FILE – A man walks past a shelter covering the exploded reactor at the Chernobyl nuclear plant, in Chernobyl, Ukraine, Thursday, April 15, 2021. When fighting from Russia’s invasion of Ukraine resulted in power cuts to the critical cooling system at the closed Chernobyl nuclear power plant, some feared that spent nuclear fuel would overheat. But nuclear experts say there’s no imminent danger because time and physics are on safety’s side