The first underground warren for disposing of spent nuclear fuel

Nearly half a kilometre underground, in the Precambrian bedrock of Olkiluoto, an island off the south-western coast of Finland, a rough-hewn gallery a few metres wide and similarly high runs dead-straight through the granite. Underfoot, the floor is a bit muddy, though mostly rocky. Overhead, steel meshing stops any fragments that might have been loosened by the drilling falling onto people’s heads. Neither hard-hat-mounted torches nor the headlights of an electric van can reach far enough into the stygian darkness to pick out the gallery’s end, some 350 metres away in the distance.