Johan Swahn, PhD, is the head of the Swedish NGO Office for Nuclear Waste Review, MKG. The ongoing projects to establish a permanent disposal site for high level nuclear waste in Finland and Sweden have run into severe problems as science has progressed. The plan is to pack the waste in copper canisters that have recently been shown to be prone to failure already during the first thousands or even hundreds of years. The intention is to surround the waste with bentonite clay, the behavior of which over the course of centuries is also a question mark.