The first sign of danger came when the dwindling crew of Ukrainian technicians running the Zaporizhzhia nuclear-power station noticed that officers from Russia’s state atomic energy company had left the premises without explanation. It was Aug. 5, and Russian soldiers were patrolling the facility. Then, at 2:40 p.m., explosions rocked an electrical switchboard, triggering the shutdown of one of only two remaining power lines running from the plant into southern Ukraine, according to plant workers. Outside, smoke billowed from a crater a few hundred yards from a substation; inside, technicians raced to check the backup diesel generators that would be needed to cool nuclear fuel at risk of overheating in an accident. It wasn’t […]