July 31, 2019 — There’s a small red hammer and sickle flag of the old Soviet Union on my dresser at home. I found it years ago on the floor of a primary school in Pripyat, the town built for workers at the doomed Chernobyl nuclear plant in what is now Ukraine. Perhaps it had been waved by a child at a state occasion, or had been left behind in the rush to evacuate Pripyat after the world’s worst nuclear disaster in April 1986.
Less than 2 miles (3 kilometers) away, the stricken, crumbling Reactor No. 4 was one of the most dangerous places on Earth. Everything for miles around, from the mushrooms in the woods to the trucks left in the parking lots to the toys in the nursery and the hospital beds, was radioactive to some degree.
Even though a dosimeter showed that after being washed down, the little flag was barely …