CHORNOBYL, Ukraine — After the Chernobyl nuclear disaster, 40 years ago Sunday, more than 300,000 people fled the towns surrounding the destroyed Unit 4 reactor that spewed lethal radiation. In 2019, Nadiia Mudryk-Mochalova fled to Chornobyl, as the Ukrainians spell it, for work — after moving to Kyiv with her daughters to escape the armed men who occupied their town in the eastern Luhansk region near the Russian border.