APOLLO, Pa.—For Patty Ameno, it is a Kodak moment from childhood that stirs many memories. She is 8 years old, dressed up for Easter in her family home's yard, clutching a doll. Her mom, as she recalls, made the doll; her dad took the photo.

But the most important memory for Ms. Ameno, now 62 and still living near this blue-collar town, is the massive factory in the photo's background. For years, it produced nuclear fuel for U.S. submarines and other customers. With a red pen she has circled drums of unknown material stacked...