Safeguarding a reprocessing plant with the method of cumulated flux

The basic principles of international safeguards and the roles of accountancy verifications and surveillance measures, especially in large bulk-handling facilities, are recalled. An approach for safeguarding large industrial reprocessing plants can be based on procedures that have been progressively developed since 1966 in the UP2 plant, where 1800 tonnes of light water reactor fuels have been reprocessed since 1976. This approach is now routinely used for management purposes. Such a reprocessing plant is essentially composed of three material balance areas (MBAs): (1) storage of irradiated fuel, (2) process area, and (3) product storage. For the process area MBA, the suggested approach is based on a combination of real-time accountancy verification of all inputs and outputs, and permanent assessment of the cumulated flux of inputs and outputs. This permanent assessment enables international inspectors to know the amount of nuclear material that is declared as being under process daily, and to compare it with the quantity that is supposed to be under process, according to the design information of the plant