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There is a long history of collaborative safeguards development between the United States and Japan. Japan has built, and continues to expand, the largest civil nuclear fuel cycle under full-scope IAEA safeguards in world. This development has posed unique challenges to the international safeguards system. Safeguards developments made through the US-Japan cooperation to address these unique challenges have significantly impacted the technologies deployed for international safeguards applications around the world. [ABSTRACT FROM AUTHOR]

The current safeguards approach for fast reactors relies exclusively on maintenance of continuity of knowledge to track the movement of fuel assemblies through these facilities. The remote handling of fuel assemblies, the visual opacity of the liquid metal coolant, and the chemical reactivity of sodium all combine and result in significant limitations on the available options to verify fuel assembly identification numbers or the integrity of these assemblies. These limitations also serve to frustrate attempts to restore the continuity-of-knowledge in instances where the information is under a variety of scenarios. The technology of ultrasonic under-sodium viewing offers new options to the safeguards community for recovering continuity-of-knowledge and applying more traditional item accountancy to fast reactor facilities. We have performed a literature review to investigate the development of under-sodium viewing technologies. In this paper we will summarize our findings and report the state of development of this technology and we will present possible applications to the fast reactor system to improve the existing safeguards approach at these reactors and in future fast reactors. [ABSTRACT FROM AUTHOR]

Remote monitoring is being applied by the International Atomic Energy Agency (IAEA) at nuclear facilities around the world. At the Monju Reactor in Japan we have designed, developed and implemented a remote monitoring approach that can serve as a model for applying remote monitoring to facilities that are already under full-scope safeguards using unattended instrumentation. Remote monitoring implementations have historically relied upon the use of specialized data collection hardware and system design features that integrate remote monitoring into the safeguards data collection system. The integration of remote monitoring and unattended data collection increases the complexity of safeguards data collection systems. This increase in complexity necessarily produces a corresponding reduction of system reliability compared to less-complex unattended monitoring systems. At the Monju facility we have implemented a remote monitoring system that is decoupled from the activity of safeguards data collection. In the completed system the function of remote data transfer is separated from the function of safeguards data collection. As such, a failure of the remote monitoring function cannot produce an associated loss of safeguards data, as is possible with integrated remote-monitoring implementations. Currently, all safeguards data from this facility is available to the IAEA on a 24/7 basis. This facility employs five radiation-based unattended systems, video surveillance and numerous optical seal systems. The implementation of remote monitoring at this facility, while increasing the complexity of the safeguards system, is designed to avoid any corresponding reduction in reliability of the safeguards data collection systems by having decoupled these functions. This design and implementation can serve as a model for implementation of remote monitoring at nuclear facilities that currently employ unattended safeguards systems. [ABSTRACT FROM AUTHOR]

Advanced fuel-cycle developments around the world currently under development are exploring the possibility of disposing of 241Am from spent fuel recycle processes by burning this material in fast reactors. For safeguards practitioners, this approach could potentially complicate both fresh- and spent-fuel safeguards measurements. The increased (α,n) production in oxide fuels from the 241Am increases the uncertainty in coincidence assay of Pu in MOX assemblies and will require additional information to make use of totals-based neutron assay of these assemblies. We have studied the behavior of 241Am-bearing MOX fuel in the fast reactor system and the effect on neutron and gamma-ray source-terms for safeguards measurements. In this paper, we will present the results of simulations of the behavior of 241Am in a fast breeder reactor system. [ABSTRACT FROM AUTHOR]