Finland’s markerless nuclear-waste vault aims to outlive civilizations

Finland is advancing Onkalo, a 430-meter-deep geological repository on Olkiluoto Island intended to contain spent nuclear fuel for about 100,000 years, using copper canisters, bentonite clay, and granite as barriers. The project’s provocative plan is to seal the tunnel and restore the surface, leaving no markers, based on the belief that any warning would draw attention rather than deter curiosity. While it is the furthest along such programs globally, it addresses only Finland’s spent fuel and does not resolve global waste or nuclear-power politics; emplacement of canisters is imminent but the marker decision remains decades away.