A consideration about Solution Monitoring application

A large scale reprocessing facility such as the Rokkasho Reprocessing Plant(RRP) should introduce the Near Real Time Material Accountancy(NR T A) as an accountancy measures for achieving the timeliness goal of safeguards. It is expected that the NRTA could detect an abrupt loss of 8kgPu during one month operation, but generally, there is some doubt in it's capability to detect a protracted loss. Due to increase of uncertainties for material balance of the NRTA, small loss may disappear in the magnitude of uncertainty. The inspectorate intends to apply some additional approaches such as the solution monitoring or the process monitoring to the chemical process of a large scale reprocessing facility for increasing of detection capability to the small loss. In this stage, those definition and function are not always clear, but it is hopefully considered that some monitoring system, which have possibilities to sense the unusual phenomenon related to the material loss, could be established by increasing of the transparency of process data. If it could be defined that the solution monitoring system monitors a rise or fall of liquid levels(L), temperatures(T) and densities(D) of subjected vessels continuously, the system may be useful for conforming validity of data used for the NRTA. However, in the process such as an extraction and an evaporation, in which the chemical component or density is variable, the solution monitoring system is impossible to apply. We would like to discuss the application possibility of solution monitoring system to the large scale reprocessing facility.