Safeguards measures are methods available to the IAEA under safeguards agreements and additional protocols to achieve the applicable safeguards objectives. INFCIRC 153* provides for the use of nuclear material accountancy as the safeguards measure of fundamental importance, with containment and surveillance as important complementary measures. These measures are applied for verifying that nuclear material inventories and flows are as declared by the State (and, under INFCIRC/66-type safeguards agreements, that non-nuclear material, services, equipment, facilities and information specified and placed under safeguards are not being used to further any proscribed purpose). Additional measures aimed at strengthening the effectiveness and improving the efficiency of safeguards were approved by the IAEA Board of Governors during 1992-1997. From a legal perspective, these measures may be categorized as follows:

• Measures that can be implemented under the existing legal authority of safeguards agreements (e.g., environmental sampling at locations to which IAEA inspectors have access during inspections)
• Measures that can only be implemented under the legal authority of additional protocols (e.g., complementary access)