Nuclear material safeguards are applied by the International Atomic Energy Agency (IAEA) world-wide in partial fulfillment of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT); see IAEA (1981a). This is the verification regime for which the most experience has been accumulated and for which the most intensive research and development has been carried out. Correspondingly, there exist many qualitative descriptions and analyses of IAEA safeguards (see for example IAEA (1981a), (1985a), (1985b), (1987)) and it is not our intention to add to them here. We'll restrict ourselves to saying that the fundamental technical basis of the IAEA's control measures is material accountancy (IAEA (1972)). This involves first and foremost the verification of reported data on material movements and inventories, either by means of independent physical measurement during on-site inspection or with the aid of tamper-proof sealing and electronic surveillance equipment, and the closing of material balances.

Like nuclear energy production itself, and notwithstanding revelations in the aftermath of the Gulf War, nuclear safeguards are presently not the issue of central importance that they once were. New verification problems and proposals for their solution now dominate international discussion.