Design Basis Threat: Innovation by the Enemy

The threats and their capabilities articulated in a State’s Design Basis Threat (DBT) provide a baseline against which operating nuclear facilities’ security systems can be designed, maintained, tested, and regulated. This paper seeks to understand the origins of the DBT, its relationship to broader national security arrangements, and whether it continues to be best relevant practice for determining the potential realistic threats to nuclear infrastructure.A conceptual filter model is proposed, which attempts to delineate the responsibilities of the State and those of the nuclear site license holder (the Duty Holder) and assist in bounding the conceptual ‘problem space’ for determining what should be considered a credible threat, and therefore what must be credibly defended against. If the model is accurate, then the DBT depends explicitly on the State’s ability to predict and define threats – something which is increasingly challenging as threats broaden and manifest in new ways. This challenge needs to be discussed and explored, taking account of previously proposed alternatives to the DBT. Finally, once a DBT is established there is a further question of how best to implement it such that appropriate and proportionate risk management can be enacted by those responsible for risk.This paper summarises findings to date of an MSc thesis.