The Trilateral Initiative is preparing for International Atomic Energy Agency (LUiA) verification of excess fissile material released itom the defense programs of the United States and the Russian Federation. Following acceptance of the material using an Attribute Verification System, the IAEA will depend on an Inventory Monitoring System to maintain Continuity of Knowledge of the large inventory of thousands of items. Recovery fiom a total loss of Continuity of Knowledge in such a large storage facility would involve an extremely costly inventory re-verification This paper presents the framework for a Layered and Segmented System Organization that is the basis for a highly reliable IMS with protection-in-depth
