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Collaborative Laboratories for Advanced Decommissioning Science; Tokyo Institute of Technology*
JAEA-Review 2024-012, 122 Pages, 2024/09
The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2022. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station (hereafter referred to "1F"), Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2021, this report summarizes the research results of the "Challenge of novel hybrid-waste-solidification of mobile nuclei generated in Fukushima Nuclear Power Station and establishment of rational disposal concept and its safety assessment" conducted in FY2022. The present study aims to establish the rational waste disposal concept of a variety of wastes generated in 1F based on the hybrid-waste-solidification by the Hot Isostatic Press (HIP) method. The ceramics form with target elements, mainly iodine, which is difficult to immobilize, and Minor actinides such as Am, an alphaemitter and heat source, are HIPed with well-studied materials such as SUS and zircaloy, which make the long-term stability evaluation and safety assessment possible.
Vauchy, R.; Sunaoshi, Takeo*; Hirooka, Shun; Nakamichi, Shinya; Murakami, Tatsutoshi; Kato, Masato
Journal of Nuclear Materials, 580, p.154416_1 - 154416_11, 2023/07
Times Cited Count:7 Percentile:94.84(Materials Science, Multidisciplinary)Collaborative Laboratories for Advanced Decommissioning Science; Tokyo Institute of Technology*
JAEA-Review 2022-072, 116 Pages, 2023/03
The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2021. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station (1F), Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2021, this report summarizes the research results of the "Challenge of novel hybrid-waste-solidification of mobile nuclei generated in Fukushima Nuclear Power Station and establishment of rational disposal concept and its safety assessment" conducted in FY2021. The present study aims to establish the rational waste disposal concept of a variety of wastes generated in 1F by the novel hybrid-waste-solidification. The phosphate form of ALPS sediment wastes containing Eu, Ce, Sr and Cs were synthesized as well as radioactive Sr, Cs and I which are both emitters, AREVA sludge and Iodine Calcium apatite were synthesized, and they were processed to the stabilization treatment such as sintering and Spark Plasma ...
Kirishima, Akira*; Akiyama, Daisuke*; Kumagai, Yuta; Kusaka, Ryoji; Nakada, Masami; Watanabe, Masayuki; Sasaki, Takayuki*; Sato, Nobuaki*
Journal of Nuclear Materials, 567, p.153842_1 - 153842_15, 2022/08
Times Cited Count:5 Percentile:72.25(Materials Science, Multidisciplinary)To understand the chemical structure and stability of nuclear fuel debris consisting of UO, Zr, and Stainless Steel (SUS) generated by the Fukushima Daiichi Nuclear Power Plant accident in Japan in 2011, simulated debris of the UO-SUS-Zr system and other fundamental component systems were synthesized and characterized. The simulated debris were synthesized by heat treatment for 1 to 12 h at 1600C, in inert (Ar) or oxidative (Ar + 2% O) atmospheres. Np and Am tracers were doped for the leaching tests of these elements and U from the simulated debris. The characterization of the simulated debris was conducted by XRD, SEM-EDX, Raman spectroscopy, and Mssbauer spectroscopy, which provided the major uranium phase of the UO -SUS-Zr debris was the solid solution of UO (s.s.) with Zr(IV) and Fe(II) regardless of the treatment atmosphere. The long-term immersion test of the simulated debris in pure water and that in seawater revealed the macro scale crystal structure of the simulated debris was chemically very stable in the wet condition for a year or more. Furthermore, the leaching test results showed that the actinide leaching ratios of U, Np, Am from the UO-SUS-Zr debris were very limited and less than 0.08 % for all the experiments in this study.
Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*
JAEA-Review 2022-009, 73 Pages, 2022/06
The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2020. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2018, this report summarizes the research results of the "Basic research on the stability of fuel debris including alloy phase" conducted from FY2018 to FY2021 (this contract was extended to FY2021). Since the final year of this proposal was FY2021, the results for four fiscal years were summarized. The present study focus on fuel debris consisting of oxide phase and alloy phase generated by the high temperature chemical reaction between structure materials (SUS pipes, pressure vessels, etc.) and fuels (melted fuels, claddings components, etc.). We synthesize the simulated debris of UO-SUS system and UO-Zr(ZrO)-SUS system by high-temperature heat treatment, and measure their chemical property and dissolution behavior in water.
Hain, K.*; Martschini, M.*; Glce, F.*; Honda, Maki; Lachner, J.*; Kern, M.*; Pitters, J.*; Quinto, F.*; Sakaguchi, Aya*; Steier, P.*; et al.
Frontiers in Marine Science (Internet), 9, p.837515_1 - 837515_17, 2022/03
Times Cited Count:12 Percentile:91.90(Environmental Sciences)Recent major advances in accelerator mass spectrometry (AMS) at the Vienna Environmental Research Accelerator (VERA) regarding detection efficiency and isobar suppression have opened possibilities for the analysis of additional long-lived radionuclides at ultra-low environmental concentrations. These radionuclides, including U, Cs, Tc and Sr, will become important for oceanographic tracer application due to their generally conservative behavior in ocean water. In particular, the isotope ratios U/U and Cs/Cs have proven to be powerful fingerprints for emission source identification as they are not affected by elemental fractionation. Improved detection efficiencies allowed us to analyze all major long-lived actinides, i.e. U, Np, Pu, Am as well as the very rare U, in the same 10 L water samples of an exemplary depth profile from the northwest Pacific Ocean. Especially for Sr analysis, our new approach has already been validated for selected reference materials (e.g. IAEA-A-12) and is ready for application in oceanographic studies. We estimate that a sample volume of only (1-3) L ocean water is sufficient for Sr as well as Cs analysis, respectively.
Ochs, M.*; Dolder, F.*; Tachi, Yukio
Applied Geochemistry, 136, p.105161_1 - 105161_11, 2022/01
Times Cited Count:6 Percentile:58.07(Geochemistry & Geophysics)Various types of radioactive wastes and environments contain organic substances that can stabilize the aqueous complexes with radionuclides and therefore lead to a decrease of sorption. The present study focuses on testing a methodology to quantify sorption reduction factors (SRFs) in the presence of organic ligands for cement systems. Three approaches for the estimation of SRFs; (1) analogy with solubility enhancement factors, (2) radionuclide speciation based on the thermodynamic calculations, and (3) experimental sorption data in ternary systems, were coupled and tested for the representative organic ligands (ISA and EDTA) and selected key radionuclides (actinides). Our approach allows to critically evaluate the dependence of SRFs for various systems on the chosen method of quantification, in accordance with the data availability for a given systems. The reliable SRFs can only be derived from the sorption measurements in ternary systems. SRF often need to be derived in the absence of such direct evidence, and estimations need to be made based on analogies and speciation information. However, such estimates may be subject to substantial uncertainties.
Fichter, S.*; Radoske, T.*; Ikeda, Atsushi
Acta Crystallographica Section E; Crystallographic Communications (Internet), 77(8), p.847 - 852, 2021/08
Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*
JAEA-Review 2020-032, 97 Pages, 2021/01
The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2019. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2018, this report summarizes the research results of the "Basic Research on the Stability of Fuel Debris Including Alloy Phase" conducted in FY2019. In the present study, we focus on fuel debris consisting of oxide phase and alloy phase generated by the high-temperature chemical reaction between structure materials (SUS pipes, pressure vessels, etc.) and fuels (melted fuels, claddings components, etc.). We synthesize the simulated debris of UO-SUS system and UO-Zr(ZrO)-SUS system by high-temperature heat treatment, and measure their chemical property and dissolution behavior in water. Also, we will conduct research and development to spectroscopically analyze secular changes of oxide phase and alloy phase in the simulated debris.
Toigawa, Tomohiro; Murayama, Rin*; Kumagai, Yuta; Yamashita, Shinichi*; Suzuki, Hideya; Ban, Yasutoshi; Matsumura, Tatsuro
UTNL-R-0501, p.24 - 25, 2020/12
This report summarizes the results obtained in FY2019 at Electron Linac Facility of University of Tokyo. The radiolysis process of a diglycolamide extractant, which is expected to be used in the separation process of minor actinides (MA), in dodecane and octanol solutions was investigated by pulse radiolysis. As a result, it was suggested that by adding alcohol, the decomposition process of the diglycolamide extractant was different from the decomposition processes in the single solvent of dodecane considered that the decomposition occurred via a radical cation species of the extractant.
Morita, Yasuji; Fukushima, Masahiro; Kashima, Takao*; Tsubata, Yasuhiro
JAEA-Data/Code 2020-013, 38 Pages, 2020/09
Critical Masses of Cm, Am and the mixture were calculated in metal-water mixtures with water reflector as a basic data for criticality safety assessment of minor actinide separation process. In the mixture of Cm-244 and Cm-245, higher ratio of Cm-245 gives smaller critical mass, but the amount of Cm-245 in the critical mass can be obtained by concentration of Cm-245 in the Cm mixture without depending on the Cm-245 ratio. Critical mass of Cm isotope mixture with 30% Cm-245 was smaller than that of Pu isotope mixture in the practical reprocessing (71% Pu-239 + 17% Pu-240 + 12% Pu-241). When Cm is separated from other element including Am and the solution is concentrated, measure for the critical accident has to be taken. Critical mass of Am-242m is smaller than that of Cm-245, but the ratio of Am-242m in the Am contained in practical spent fuel is small enough, about several percent, and therefore the critical accident by Am does not have to be considered. That by the mixture of Am and Cm does not either.
Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*
JAEA-Review 2019-035, 61 Pages, 2020/03
JAEA/CLADS, had been conducting the Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development (hereafter referred to "the Project") in FY2018. The Project aims to contribute to solving problems in nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2018, this report summarizes the research results of the "Basic Research on the Stability of Fuel Debris Including Alloy Phase". In the present study, we focus on fuel debris consisting of oxide phase and alloy phase generated by the high-temperature chemical reaction between structure materials (SUS pipes, pressure vessels, etc.) and fuels (melted fuels, claddings components, etc.). We synthesize the simulated debris of UO-SUS system and UO-Zr(ZrO)-SUS system by high-temperature heat treatment, and measure their chemical property and dissolution behavior in water. Also, we will conduct research and development to spectroscopically analyze secular changes of oxide phase and alloy phase in the simulated debris.
Watanabe, So; Senzaki, Tatsuya; Shibata, Atsuhiro; Nomura, Kazunori; Takeuchi, Masayuki; Nakatani, Kiyoharu*; Matsuura, Haruaki*; Horiuchi, Yusuke*; Arai, Tsuyoshi*
Journal of Radioanalytical and Nuclear Chemistry, 322(3), p.1273 - 1277, 2019/12
Times Cited Count:5 Percentile:44.57(Chemistry, Analytical)Kofuji, Hirohide; Watanabe, So; Takeuchi, Masayuki; Suzuki, Hideya; Matsumura, Tatsuro; Shiwaku, Hideaki; Yaita, Tsuyoshi
Progress in Nuclear Science and Technology (Internet), 5, p.61 - 65, 2018/11
Haga, Yoshinori; Yamamura, Tomoo*
Nihon Genshiryoku Gakkai-Shi ATOMO, 60(3), P. 181, 2018/03
no abstracts in English
Rai, D.*; Kitamura, Akira
Journal of Chemical Thermodynamics, 114, p.135 - 143, 2017/11
Times Cited Count:11 Percentile:20.39(Thermodynamics)Isosaccharinic acid is a cellulose degradation product that can form in low-level nuclear waste repositories and is known to form strong complexes with many elements, including actinides, disposed of in these repositories. We (1) reviewed the available data for deprotonation and lactonisation constants of isosaccharinic acid, and the isosaccharinate binding constants for Ca, Fe(III), Th, U(IV), U(VI), Np(IV), Pu(IV), and Am(III), (2) summarized complexation constant values for predicting actinide behavior in geologic repositories in the presence of isosaccharinate, and (3) outlined additional studies to acquire reliable thermodynamic data where the available data are inadequate.
Harada, Hideo; Iwamoto, Osamu; Iwamoto, Nobuyuki; Kimura, Atsushi; Terada, Kazushi; Nakao, Taro; Nakamura, Shoji; Mizuyama, Kazuhito; Igashira, Masayuki*; Katabuchi, Tatsuya*; et al.
EPJ Web of Conferences, 146, p.11001_1 - 11001_6, 2017/09
Times Cited Count:2 Percentile:76.51(Nuclear Science & Technology)Takeuchi, Masayuki; Sano, Yuichi; Watanabe, So; Nakahara, Masaumi; Aihara, Haruka; Kofuji, Hirohide; Koizumi, Tsutomu; Mizuno, Tomoyasu
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 6 Pages, 2017/04
Sasaki, Shinji; Tanno, Takashi; Maeda, Koji
Proceedings of 54th Annual Meeting of Hot Laboratories and Remote Handling (HOTLAB 2017) (Internet), 6 Pages, 2017/00
During irradiation in a fast reactor, the microstructure change of the mixed oxide fuels and the changes of element distributions occur because of a radial temperature gradient. Therefore, it is important to study the irradiation behavior of MA-MOX for advancement of fast reactor fuels. In order to make detailed observations of microstructure and elemental analyses of MA-MOX, irradiated MA-MOX specimens were carried out PIE by using a FE-SEM equipped with WDX. Because fuel samples have high radio activities and emit alpha-particles, the instrument was modified. the instrument was installed in a lead shield box and the control unit was separately located outside the box. The microstructure changes were observed in irradiated MA-MOX specimen. The characteristic X-rays peaks were detected successfully. By measuring the intensities of characteristic X-rays, it was tried quantitative analysis of U, Pu, Am along radial direction of irradiated specimen.
Watanabe, So; Nomura, Kazunori; Kitawaki, Shinichi; Shibata, Atsuhiro; Kofuji, Hirohide; Sano, Yuichi; Takeuchi, Masayuki
Procedia Chemistry, 21, p.101 - 108, 2016/12
Times Cited Count:14 Percentile:99.08(Chemistry, Inorganic & Nuclear)