The elevator display reads "433", the number of meters below ground. The doors slide open, revealing the entrance to what is expected to be the world's first permanent repository for radioactive spent nuclear fuel. Blasted into 1.9 billion-year-old stable bedrock in Eurajoki, southwest Finland, the geological repository for spent nuclear waste – dubbed Onkalo, which means "cave" in Finnish – is nearly ready to start operations. Countries have been wrestling with what to do with dangerous