Small and advanced nuclear technologies are viewed as key to meeting future low-carbon dioxide energy demands. Big Tech companies are even planning to build their own nuclear reactors to power the digital revolution, including those that are yet to leave the drawing board. Building disposal solutions for the radioactive waste that these mainly novel reactors, which come with novel fuel, is essential too. Experience from 70 years of nuclear energy generation tells us that focusing on the cradle, and not adequately considering the grave of nuclear reactors, leads to significant and unconstrained costs that investors and governments might prefer to avoid.