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| Fig. 1: Rokkasho Reprocessing Plant (Source: Wikimedia Commons) |
After the Fukushima Daiichi nuclear disaster in 2011, Japan shut down its entire fleet of nuclear power plants, pending safety inspections and regulation checks. However, the Japanese government continues to proceed with its previous plans of a closed nuclear fuel cycle, meaning Japan intends to separate plutonium from its spent reactor fuel for reuse. [1] The Rokkasho Reprocessing Plant (Fig. 1) will play a central role in closing the nuclear fuel cycle in Japan - separating plutonium and uranium in spent fuel from highly radioactive fission products so that the plutonium and uranium can be used in nuclear fuel again. [1] Since Japan only manages to produce 4% of its energy domestically, reprocessing would make nuclear fuel a semi-domestic energy source. [2]
The Rokkasho Reprocessing Plant, approximately 3,800,000 square meters in size, is the first commercial plant in Japan, adopting technology developed from over 40 years of operations results in France and the United Kingdom as well as operating experience from the Japan Atomic Energy Agency. [3] Located in Oaza Obuchi, Rokkasho-mura, Kamikita-gun, Aomori Prefecture, the reprocessing plant will be able to process 4.8 tons of spent fuel a day with an annual reprocessing capacity of 800 tons. [3] Therefore, the plant will be able to reprocess the spent fuel produced from about 40 reactors each 1,000 MW in size. It will also be able to store over 3,000 tons of spent fuel for future reprocessing. [3] Construction of the plant started in 1993, and after undergoing water flow operational tests, chemical tests, and uranium tests, the plant is currently undergoing the final stage, "Final Commissioning" tests, and is set to start full operations by the end of 2018. Up to now, the plant has received a total of 3,393 tons of spent fuel.
The International Atomic Energy Agency has learned several lessons from the construction and development of the Rokkasho Reprocessing Plant. In all, the lessons learned from the implementation of safeguards at the plant fall into the following categories: general design and operating features, capabilities for and ease of design examination and verification, designing in a materials control and accountancy system, designing in measurement systems, designing in process monitoring and C/S, designing in sampling and analytical capabilities, and designing in system security and authentication. [4] Specifically, system security and authentication remains a growing concern for nuclear facilities across the globe as the digital age continues to redefine data storage and plant connectivity.
© John Solitario. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] M. Takubo and F. Hippel, "Ending Reprocessing in Japan," International Panel of Fissile Materials, Research Report No. 12, November 2013.
[2] C. Dunn, "Nuclear Reprocessing in Japan," Physics 241, Stanford University, Winter 2011.
[3] "Rokkasho Reprocessing Plant," Japan Nuclear Fuel Limited, October 2014.
[4] S. J. Johnson and M. Ehinger, "Designing and Operating for Safeguards: Lessons Learned from the Rokkasho Reprocessing Plant," Pacific Northwest National Laboratory, PNNL-19626, August 2010.
