Standing in a 1960s industrial building by the German Baltic Sea coast, Florian Grose, holds a dosimeter as he moves towards a corner of the room. It starts beeping furiously. "That's around 10 microsieverts," he says, dressed in protective overalls. A normal dose rate is under 0.2 microsieverts. "This is an area where I'd say we maybe should move a meter away. You shouldn't stand or lie here for an hour," Grose, a radiation protection worker, warns in a disarmingly jovial tone. Inside special building one of the former nuclear power plant, parts of the wall are uneven and pockmarked — the result of workers hammering off layers of concrete, hunting for radioactive contamination. It's been one of the "most difficult buildings to decontaminate and dismantle," explains Kurt Radlof, who handles communications for the plant.…