Vol.9 No.3 2017
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Research paper−139−Synthesiology - English edition Vol.9 No.3 pp.139 –154 (Feb. 2017) decontamination and measurement technologies using PB nanoparticles having high adsorption capacities for radioactive cesium.Decontamination technology is an extremely urgent topic. Therefore, R&D has been conducted more rapidly than a regular schedule might allow. Our core material is PB nanoparticles. Although R&D activities are mainly conducted from the standpoint of materials science, for the practical application of decontamination technology, it has also been necessary to combine diverse specialties such as chemical engineering, geo-engineering, and agriculture. Because AIST is a research institute, it cannot engage in final commercial projects. Therefore, the developed technologies must be transferred to a company to carry out commercial tasks. It is also necessary to pursue coordination with the national government and local governments, particularly with efforts of coordination with the local area in which the pilot plant tests would be done.As described in this paper, we address the example of the decontamination technology of incinerated ash using PB nanoparticles. Details of the R&D are presented in Chapter 2. The strategy and management for conducting this technological development are presented in Chapter 3.2 Development of incinerated ash decontamination technology2.1 Technological backgroundThe radioactive cesium adsorbent, our core technology, 1 Background: Radiation leakage accident and AIST effortsAs a consequence of the great earthquake which occurred on March 11, 2011, a giant tsunami struck the Fukushima Daiichi Nuclear Power Plant operated by Tokyo Electric Power Company. In the aftermath, the nuclear reactors, which could not be cooled, leaked radioactive materials. Most of those leaked materials had a low boiling point, which exacerbated their release: an estimated 1.6 × 1017 Bq of iodine−131 and 1.5 × 1017 Bq of cesium−137 were ejected into the environment.[1] Because iodine and cesium exist as salt compounds at room temperature, they fell on the ground to contaminate the soil, or dissolved in river and sea waters. The respective half-lives of cesium−134 and cesium−137 are approximately two years and 30 years. Therefore, their effects are expected to persist for a long time. The Japanese government has held the decontamination of radioactive cesium from the environment as an urgent task, and has concentrated on research and development to achieve that objective.Great efforts for decontamination have been undertaken at AIST for various developments, such as those of decontamination technology for contaminated water, soil, and incinerated ash using Prussian blue (PB) nanoparticles,[2]–[6] of a concentrator for analyzing ultra-trace radioactive materials in environmental water,[7][8] of reference materials to evaluate brown rice contamination,[9] of dynamic evaluation methods for radioactive cesium in the environment,[10][11] and of decontamination cost estimation.[12] We specifically examined the development of - Utilization and application of nanoparticles as an adsorbent-The accident at the Fukushima Daiichi Nuclear Power Station in 2011 spurred rapid research and development at AIST for radioactive cesium decontamination systems. In this paper, we introduce the development of an ash-decontamination technology that uses Prussian blue (PB) nanoparticles. We developed all aspects of the system using a combination of fundamental technologies, which included optimization of the PB nanoparticle structure for use as a cesium adsorbent, composite fabrication as granules for use as an adsorbent, and extraction of radioactive cesium from contaminated ash. All aspects of development were achieved rapidly through close collaboration among materials science, computational science, and geology researchers. Collaboration with private companies was also effective.Radioactive cesium decontamination technology for ashKeywords : Prussian blue, nanoparticle, radioactive cesium, decontamination, ash [Translation from Synthesiology, Vol.9, No.3, p.139–153 (2016)]Tohru Kawamoto1*, Hisashi Tanaka1, Yukiya Hakuta1, Akira Takahashi1, Durga Parajuli1, Kimitaka Minami1, Tetsuo Yasutaka2 and Tatsuya Uchida11. Nanomaterials Research Institute, AIST Tsukuba Central 5, 1-1-1 Higashi, Tsukuba 305-8565, Japan * E-mail: , 2. Research Institute for Geo-Resources and Environment, AIST Tsukuba Central 7, 1-1-1 Higashi, Tsukuba 305-8567, JapanOriginal manuscript received March 29, 2016, Revisions received May 16, 2016, Accepted June 6, 2016

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