Abstract
Due to a large plutonium (Pu) throughput and high burn-up fuel in an advanced reprocessing plant, we have the responsibility to undertake the inevitable burden of nuclear material accountancy (NMA) to meet the International Atomic Energy Agency (IAEA) safeguards criteria. A large amount of sampling analysis and inspectors' activities result in a great cost in facility operation to verify no concealment and undeclared use of Pu. In addition to NMA, containment and surveillance (C/S), process monitoring (PM), and curium (Cm) balance have been used for the safeguards activities to complement NMA. However, except for NMA, any mathematical or regulatory formalism in the safeguards measures have not been presented so far, therefore it is difficult to evaluate the cost-effective performance of the safeguards system. In order to design an advanced safeguards system for the fast reactor fuel cycle, the JAEA has started to develop a safeguards system simulator. A NMA core in the simulator is composed of a near-real-time accounting (NRTA) code which had been already developed and applied to investigate the NMA characteristics of JAEA facilities. A "multivariate and multi-scale core" is based on a multivariate mathematical analysis combined with a multi-scale statistical process analysis making use of a wavelet decomposition forms safeguards envelope, which provides a control and monitoring system logic. Multi-scale principle component analysis of the core had been applied to "material unaccounted for" (MUF). A concept of multiple optimization core is proposed as the safeguards formalism, with probabilistic risk analysis and cost-performance characteristics of the safeguards system, is discussed in the presentation. Flow meter and non-destructive analysis can be more broadly applied to the system in a cost-effective manner. A virtual design and objective-driven model will be developed in the simulator in the future to support an effective safeguards design and to develop a "walk-through" virtual plant model.
