Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 194

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Structure, stability, and actinide leaching of simulated nuclear fuel debris synthesized from UO$$_{2}$$, Zr, and stainless-steel

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:0

To understand the chemical structure and stability of nuclear fuel debris consisting of UO$$_{2}$$, Zr, and Stainless Steel (SUS) generated by the Fukushima Daiichi Nuclear Power Plant accident in Japan in 2011, simulated debris of the UO$$_{2}$$-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 1600$$^{circ}$$C, in inert (Ar) or oxidative (Ar + 2% O$$_{2}$$) atmospheres. $$^{237}$$Np and $$^{241}$$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 M$"o$ssbauer spectroscopy, which provided the major uranium phase of the UO $$_{2}$$-SUS-Zr debris was the solid solution of U$$^{mathrm{IV}}$$O$$_{2}$$ (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$$_{2}$$-SUS-Zr debris were very limited and less than 0.08 % for all the experiments in this study.

JAEA Reports

Basic research on the stability of fuel debris including alloy phase (Contract research); FY2020 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*

JAEA-Review 2022-009, 73 Pages, 2022/06

JAEA-Review-2022-009.pdf:2.08MB

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$$_{2}$$-SUS system and UO$$_{2}$$-Zr(ZrO$$_{2}$$)-SUS system by high-temperature heat treatment, and measure their chemical property and dissolution behavior in water. Also, we will conduct

JAEA Reports

Development of a new corrosion mitigation technology using nanobubbles toward corrosion mitigation in PCV system under the influence of $$alpha$$/$$beta$$/$$gamma$$-rays radiolysis (Contract research); FY2020 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*

JAEA-Review 2022-002, 85 Pages, 2022/06

JAEA-Review-2022-002.pdf:3.39MB

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 FY2020, this report summarizes the research results of the "Development of a new corrosion mitigation technology using nanobubbles toward corrosion mitigation in PCV system under the influence of $$alpha$$/$$beta$$/$$gamma$$-rays radiolysis" conducted in FY2020. In this work, in order to ensure the long-term reliability of steel structures that ensure important confinement functions in the debris removal process, such as existing PCVs and newly constructed negative pressure maintenance systems and piping, corrosion phenomena in wet environments where $$alpha$$- and $$beta$$-ray emitting nuclides come into contact with steel are clarified for the first time. At the same time, we will develop a new corrosion prevention technology that has excellent basic applicability to PCVs and has

Journal Articles

Marking actinides for separation; Resonance-enhanced multiphoton charge transfer in actinide complexes

Matsuda, Shohei; Yokoyama, Keiichi; Yaita, Tsuyoshi; Kobayashi, Toru; Kaneta, Yui; Simonnet, M.; Sekiguchi, Tetsuhiro; Honda, Mitsunori; Shimojo, Kojiro; Doi, Reisuke; et al.

Science Advances (Internet), 8(20), p.eabn1991_1 - eabn1991_11, 2022/05

 Times Cited Count:0 Percentile:0(Multidisciplinary Sciences)

no abstracts in English

Journal Articles

Deep groundwater physicochemical components affecting actinide migration

Kirishima, Akira*; Terasaki, Mariko*; Miyakawa, Kazuya; Okamoto, Yoshihiro; Akiyama, Daisuke*

Chemosphere, 289, p.133181_1 - 133181_12, 2022/04

 Times Cited Count:0 Percentile:0(Environmental Sciences)

no abstracts in English

Journal Articles

Developing accelerator mass spectrometry capabilities for anthropogenic radionuclide analysis to extend the set of oceanographic tracers

Hain, K.*; Martschini, M.*; G$"u$lce, 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:1 Percentile:0.02(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 $$^{233}$$U, $$^{135}$$Cs, $$^{99}$$Tc and $$^{90}$$Sr, will become important for oceanographic tracer application due to their generally conservative behavior in ocean water. In particular, the isotope ratios $$^{233}$$U/$$^{236}$$U and $$^{137}$$Cs/$$^{135}$$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. $$^{236}$$U, $$^{237}$$Np, $$^{239, 240}$$Pu, $$^{241}$$Am as well as the very rare $$^{233}$$U, in the same 10 L water samples of an exemplary depth profile from the northwest Pacific Ocean. Especially for $$^{90}$$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 $$^{90}$$Sr as well as $$^{135}$$Cs analysis, respectively.

JAEA Reports

Development of extremely small amount analysis technology for fuel debris analysis (Contract research); FY2020 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*

JAEA-Review 2021-056, 98 Pages, 2022/02

JAEA-Review-2021-056.pdf:9.08MB

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 FY2019, this report summarizes the research results of the "Development of extremely small amount analysis technology for fuel debris analysis" conducted in FY2020. The fuel debris retrieved from the Fukushima Daiichi Nuclear Power Station (1F) is analyzed in the second building of the Okuma Analysis and Research Center. The characteristics of fuel debris, such as the mixture of nuclear fuel, reactor components, and concrete, are not clear, and its analysis will be the first attempt in the world. Understanding the properties of fuel debris is necessary for handling, criticality control, storage control, etc. A key technique is the chemical analysis of actinide nuclides. We develop sample pretreatment technology and separation/analysis process required for chemical analysis.

Journal Articles

Decrease of radionuclide sorption in hydrated cement systems by organic ligands; Comparative evaluation using experimental data and thermodynamic calculations for ISA/EDTA-actinide-cement systems

Ochs, M.*; Dolder, F.*; Tachi, Yukio

Applied Geochemistry, 136, p.105161_1 - 105161_11, 2022/01

 Times Cited Count:0 Percentile:0.01(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.

Journal Articles

Structure of the {U$$_{13}$$} polyoxo cluster U$$_{13}$$O$$_{8}$$Cl$$_{x}$$(MeO)$$_{38-x}$$ (x = 2.3, MeO = methoxide)

Fichter, S.*; Radoske, T.*; Ikeda, Atsushi

Acta Crystallographica Section E; Crystallographic Communications (Internet), 77(8), p.847 - 852, 2021/08

Journal Articles

Neutron capture cross sections of curium isotopes measured with ANNRI at J-PARC

Kawase, Shoichiro*; Kimura, Atsushi; Harada, Hideo; Iwamoto, Nobuyuki; Iwamoto, Osamu; Nakamura, Shoji; Segawa, Mariko; Toh, Yosuke

Journal of Nuclear Science and Technology, 58(7), p.764 - 786, 2021/07

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

JAEA Reports

Development of extremely small amount analysis technology for fuel debris analysis (Contract research); FY2019 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*

JAEA-Review 2020-064, 95 Pages, 2021/02

JAEA-Review-2020-064.pdf:9.48MB

JAEA/CLADS had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project in FY2019. Among the adopted proposals in FY2019, this report summarizes the research results of the "Development of extremely small amount analysis technology for fuel debris analysis" conducted in FY2019.

JAEA Reports

Basic research on the stability of fuel debris including alloy phase (Contract research); FY2019 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*

JAEA-Review 2020-032, 97 Pages, 2021/01

JAEA-Review-2020-032.pdf:4.16MB

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$$_{2}$$-SUS system and UO$$_{2}$$-Zr(ZrO$$_{2}$$)-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.

Journal Articles

Re-evaluation of radiation-energy transfer to an extraction solvent in a minor-actinide-separation process based on consideration of radiation permeability

Toigawa, Tomohiro; Tsubata, Yasuhiro; Kai, Takeshi; Furuta, Takuya; Kumagai, Yuta; Matsumura, Tatsuro

Solvent Extraction and Ion Exchange, 39(1), p.74 - 89, 2021/00

 Times Cited Count:0 Percentile:0(Chemistry, Multidisciplinary)

Absorbed-dose estimation is essential for evaluation of the radiation feasibility of minor-actinide-separation processes. We propose a dose-evaluation method based on radiation permeability, with comparisons of heterogeneous structures seen in the solvent-extraction process, such as emulsions forming in the mixture of the organic and aqueous phases. A demonstration of radiation-energy-transfer simulation is performed with a focus on the minor-actinide-recovery process from high-level liquid waste with the aid of the Monte Carlo radiation-transport code PHITS. The simulation results indicate that the dose absorbed by the extraction solvent from alpha ray depends upon the emulsion structure, and that from beta and gamma ray depends upon the mixer-settler-apparatus size. Non-negligible contributions of well-permeable gamma rays were indicated in terms of the plant operation of the minor-actinide-separation process.

Journal Articles

Study on the mechanism of radiolytic degradation of an extractant for minor actinides separation

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.

JAEA Reports

Critical mass evaluation of minor actinides in aqueous solution; Data for criticality safety assessment of separation process

Morita, Yasuji; Fukushima, Masahiro; Kashima, Takao*; Tsubata, Yasuhiro

JAEA-Data/Code 2020-013, 38 Pages, 2020/09

JAEA-Data-Code-2020-013.pdf:1.94MB

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.

Journal Articles

Thermodynamic and thermophysical properties of the actinide nitrides

Uno, Masayoshi*; Nishi, Tsuyoshi*; Takano, Masahide

Comprehensive Nuclear Materials, 2nd Edition, Vol.7, p.202 - 231, 2020/08

On the thermodynamic and thermophysical properties of the actinide nitrides in Comprehensive Nuclear Materials published by Elsevier as the first edition in 2012, we have revised them by adding some brand-new data. The main topics added are the solid solubility of the actinide nitrides into the zirconium nitride matrix for transmutation fuel, the lattice expansion of actinide nitrides induced by self-irradiation damage, the influence of defects accumulation on thermal conductivity, and the thermal expansion in curium nitride lattice.

Journal Articles

Role of the hydroxo group in the coordination of citric acid to trivalent americium

Tamain, C.*; Bonato, L.*; Aupiais, J.*; Dumas, T.*; Guillaumont, D.*; Barkleit, A.*; Berthon, C.*; Solari, P. L.*; Ikeda, Atsushi; Guilbard, P.*; et al.

European Journal of Inorganic Chemistry, 2020(14), p.1331 - 1344, 2020/04

 Times Cited Count:1 Percentile:14.43(Chemistry, Inorganic & Nuclear)

The molecular characterization based on multi-technique approach has led to major highlights on revealing the coordination environment of americium (Am) surrounded by citric acid (H$$_{3}$$CitH). The structure of the different complexes at pH 1 and 3 are described. These characterizations are made possible by the comparison of the americium-citric acid system with the americium-tricarballylic acid (one analogue of the citric acid without the alpha-hydroxo group).

JAEA Reports

Basic research on the stability of fuel debris including alloy phase (Contract research); FY2018 Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development

Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*

JAEA-Review 2019-035, 61 Pages, 2020/03

JAEA-Review-2019-035.pdf:2.9MB

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$$_{2}$$-SUS system and UO$$_{2}$$-Zr(ZrO$$_{2}$$)-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.

Journal Articles

Improvement in flow-sheet of extraction chromatography for trivalent minor actinides recovery

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:0 Percentile:0.01(Chemistry, Analytical)

Journal Articles

Characteristics of TPDN/SiO$$_{2}$$-P adsorbent for MA(III) recovery

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

194 (Records 1-20 displayed on this page)