New nuclear fuel bears no threat of a terrorist attack in any realistic scenario. This is due to the fact that its inherent radiation hazard is negligible, and chemical toxicity is relatively low. Spent nuclear fuel (SNF) like any highly radioactive material represents potential hazard in the case of attempted theft – above all, to the attacker.
However, an attempt of this kind has no chance of success. Firstly, all the facilities dealing with SNF (as with a nuclear power plant, special trains for transportation, storage and processing plants) are under increased security guard with special authorisation powers. Secondly, the technology of SNF handling fully eliminates human contact with it. And thirdly the bulk, weight and other physical characteristics of spent fuel (a massive structure weighing several hundred kilograms with a high level of radioactivity) make SNF very unattractive for attempts of theft even for terrorist purposes.