BATAAN, Philippines — They’d grown old together, the nuclear plant and its caretaker.

Willie Torres had been there at the start in the 1970s, when the plant was still being built, a $2.3 billion project set to become Asia’s first venture into nuclear energy. He stayed on as a technician when the plant became dogged by scandal. And he remained as one of a handful of staff when, in the wake of the Chernobyl disaster, the government ordered it mothballed.