Argentesi,-T.; Casilli,-T. (Christian Rovsing International, Copenhagen (Denmark)); Costantini,-L.; Dondi,-M.G.; Franklin,-M. (General Systems, SpA (Italy)). This document describes a nuclear material accountancy system which has been developed using the ADABAS data base management system and is implemented on the JRC-Ispra computer. Throughout the report, the data base system is referred to as ''ISADAM'', i.e. International Safeguards Data Management System. The system provides tools for a safeguards authority to decide whether an operators MUF (Material Unaccounted For) can be accounted for as an accumulation of operator measurement errors. The principle objective of the applications programs described here is to provide a variance analysis of MUF in which the variance of MUF is computed as a function of the accounting declarations and the error characteristics of the operator measurement system. A overview of ISADAM is presented; then, a detailed description of the processing applied by the system is given. A description of the parameter information required by the four autonomous programs ISADAM is presented. In developing ISADAM, one of the prime factors taken into consideration was the ease with which it could be used.
