In public discussion, high-level nuclear waste is often referred to as an exceptional environmental problem. It is indeed an exceptional problem, but not primarily because of the permanent threat that nuclear waste poses to future generations, as is usually argued. Its exceptionality rather stems from socio-technical factors that create deadlocks and dilemmas, thus hampering and delaying decision-making. This article provides an overview of major socio-technical issues pertaining to nuclear waste, including some that have been neglected in previous literature, and thus contributes to technology assessment in this field.