The Evolution of Safeguards Technology for Bulk Handling Facilities for Nuclear Fuel Cycle in Japan: from Ningyo-toge Tokai to Rokkasho

摘要

Japan is the only non-nuclear-weapon country with a full nuclear fuel cycle including uranium enrichment and reprocessing facilities. The evolution of technologies has been instrumental in improving facility and safeguards efficiency. Older facilities with small material throughput operated almost manually. In contrast, more modern facilities with large material throughput were designed for improved throughput and accountancy and introduced state-of-art technologies, e.g. remote monitoring, unattended measurements. Japan has the experience of a series of new types of nuclear facilities which are pilot scale through commercial size. This paper presents the efforts and evolutions of the safeguards technology development in Japan, through international cooperation. This paper will look at a number of different plants which have been and will be required technology developments. The first to be addressed is the pilot scale enrichment plant in Ningyo-toge, (started operation in 1979) and the impact of the Hexapartite Safeguards Project (HSP) which was formed by the international community. Some of the technologies developed under this project were later introduced at the Rokkasho Enrichment Plant. The implementation of international safeguards at the Tokai Reprocessing Plant (TRP) (started operation in 1981) was promoted by the Tokai Advanced Safeguards Technology Exercise (TASTEX) following the US-Japan joint statement for the reprocessing in 1977. These safeguards experiences and developed technologies at TRP contributed to the Large Scale Reprocessing Safeguards (LASCAR) forum from 1988-1992, which turned to be a fundamental concept for safeguards approach and instrumentation for the Rokkasho Reprocessing Plant. The first MOX fuel fabrication facility was constructed in 1966 in Tokai. Then, the more modern facility with a lot of automated fuel fabrication apparatuses was constructed to supply MOX fuel for the Fast Breeder Reactor in Tokai. The various unattended nondestructive assay (NDA) systems and data acquisition systems were developed through the JAEA-USDOE cooperation program. The technologies developed for safeguarding these types of facilities have continued to develop and will be applied to the Rokkasho J-MOX plant. As mentioned above, continuous R&D has been conducted in Japan from the pilot scale through commercial size plant. This evolution of technologies has benefited both the operator and IAEA.