The evolution of legal approaches to controlling nuclear and radiological weapons and combating the threat of nuclear terrorism

This chapter traces the evolution of international law related to the weaponization of nuclear and other radioactive materials, focusing in particular on the law pertaining to preventing acts of nuclear terrorism. International efforts to control atomic energy have evolved substantially since the only use of nuclear weapons, against Japan, in 1945. Unlike for chemical and biological weapons, whose legal regimes are centred on total bans of such weapons, the legal regime for nuclear weapons founded in the Treaty on the Non-Proliferation of Nuclear Weapons codifies a situation in which certain States retain weapons, pledging to negotiate toward disarmament, while others forego them and submit to a system of verification to ensure no diversion of nuclear energy from peaceful uses to nuclear weapons or other nuclear explosive devices. The recognition that physical protection of nuclear material and nuclear facilities from acts such as theft and sabotage was also highly important to both non-proliferation and radiation safety, but was not provided for under the safeguards system set up to detect and deter diversion by States of nuclear material to non-peaceful purposes, precipitated the nuclear security framework, starting with physical protection recommendations developed under the auspices of the International Atomic Energy Agency and the Convention on the Physical Protection of Nuclear Material. Subsequent developments related to nuclear security have been driven primarily by two issues: first, concerns regarding vulnerability of a significant amount of nuclear and other radioactive material, not necessarily part of weapons programmes, particularly following the end of the Cold War; and second, the threat that terrorists would obtain and use such materials. The latter issue came to the fore in the wake of the terrorist attacks on 11 September 2001, displaying a new strain of mass-casualty international terrorism. These attacks were a transformative event for the area of nuclear security, leading to a number of actions aimed at strengthening the international legal framework. However, from the beginning, nuclear security has been formulated as fundamentally a national responsibility of States pursuant, where applicable, to certain international obligations. National sensitivities continue to affect the extent to which States are willing to enter into legally binding agreements. With that in mind, the present chapter looks at methods by which the law evolves and considers how they have been put into practice with respect to nuclear security in light of said national sensitivities and in response to perceived threats