Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 136

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

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

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.

JAEA Reports

Upgrading of recovery method for radioactive microparticles by heavy liquid separation aiming to volume reduction of contaminated soil (Contract research); FY2020 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; University of Tsukuba*

JAEA-Review 2021-023, 49 Pages, 2021/12

JAEA-Review-2021-023.pdf:2.39MB

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 FY2018, this report summarizes the research results of the "Upgrading of recovery method for radioactive microparticles by heavy liquid separation aiming to volume reduction of contaminated soil" conducted from FY2018 to FY2020. Since the final year of this proposal was FY2020, the results for three fiscal years were summarized. The present study aims to develop a novel method to reduce the volume of contaminated soil caused by an accident at the Fukushima Daiichi Nuclear Power Station. The heavy liquid separation method, which was optimized in the previous year, was applied to nine soils collected in Fukushima Prefecture. As a result, radioactivity concentration and weight of the contaminated soils were reduced by half at six sites by separating the soils into two fractions u

Journal Articles

Additive-free hydrothermal leaching method with low environmental burden for screening of strontium in soil

Kato, Takuma*; Nagaoka, Mika; Guo, H.*; Fujita, Hiroki; Aida, Taku*; Smith, R. L. Jr.*

Environmental Science and Pollution Research, 28(39), p.55725 - 55735, 2021/10

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

In this work, hydrothermal leaching was applied to simulated soils (clay minerals vermiculite, montmorillonite, kaolinite) and actual soils (Terunuma, Japan) to generate organic acids with the objective to develop an additive-free screening method for determination of Sr in soil. Stable strontium (SrCl$$_{2}$$) was adsorbed onto soils for study and ten organic acids were evaluated for leaching Sr from simulated soils under hydrothermal conditions (120 to 200$$^{circ}$$C) at concentrations up to 0.3 M. For strontium-adsorbed vermiculite (Sr-V), 0.1 M citric acid was found to be effective for leaching Sr at 150$$^{circ}$$C and 1 h treatment time. Based on these results, the formation of organic acids from organic matter in Terunuma soil was studied. Hydrothermal treatment of Terunuma soil produced a maximum amount of organic acids at 200$$^{circ}$$C and 0.5 h reaction time. To confirm the possibility for leaching of Sr from Terunuma soil, strontium-adsorbed Terunuma soil (Sr-S) was studied. For Sr-S, hydrothermal treatment at 200$$^{circ}$$C for 0.5 h reaction time allowed 40% of the Sr to be leached at room temperature, thus demonstrating an additive-free method for screening of Sr in soil. The additive-free hydrothermal leaching method avoids calcination of solids in the first step of chemical analysis and has application to both routine monitoring of metals in soils and to emergency situations.

JAEA Reports

Development of the Sintering Solidification Method for Spent Zeolite to Long-term Stabilization (Contract research); FY2019 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Shibaura Institute of Technology*

JAEA-Review 2020-049, 78 Pages, 2021/01

JAEA-Review-2020-049.pdf:5.85MB

JAEA/CLADS had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project. Among the adopted proposals in FY2018, this report summarizes the research results of the "Development of the Sintering Solidification Method for Spent Zeolite to Long-term Stabilization" conducted in FY2019.

JAEA Reports

Upgrading of recovery method for radioactive microparticles by heavy liquid separation aiming to volume reduction of contaminated soil (Contract research); FY2019 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; University of Tsukuba*

JAEA-Review 2020-037, 53 Pages, 2020/12

JAEA-Review-2020-037.pdf:3.46MB

JAEA/CLADS had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project in FY2019. Among the adopted proposals in FY2018, this report summarizes the research results of the "Upgrading of Recovery Method for Radioactive Microparticles by Heavy Liquid Separation Aiming to Volume Reduction of Contaminated Soil" conducted in FY2019.

JAEA Reports

Annual report for FY2018 on the activities of Department of Decommissioning and Waste Management (April 1, 2018 - March 31, 2019)

Department of Decommissioning and Waste Management

JAEA-Review 2020-012, 103 Pages, 2020/08

JAEA-Review-2020-012.pdf:8.17MB

This report describes the activities of Department of Decommissioning and Waste Management (DDWM) in Nuclear Science Research Institute (NSRI) in the period from April 1, 2018 to March 31, 2019. The report covers organization and missions of DDWM, outline and operation/maintenance of facilities which belong to DDWM, treatment and management of radioactive wastes, decommissioning activities, and related research and development activities which were conducted in DDWM.

Journal Articles

Selective removal of radiocesium from micaceous clay for post-accident soil decontamination by temperature-controlled Mg-leaching in a column

Yin, X.; Zhang, L.*; Meng, C.*; Inaba, Yusuke*; Wang, X.*; Nitta, Ayako; Koma, Yoshikazu; Takeshita, Kenji*

Journal of Hazardous Materials, 387, p.121677_1 - 121677_10, 2020/04

JAEA Reports

Development of the sintering solidification method for spent zeolite to long-term stabilization (Contract research); FY2018 Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development

Collaborative Laboratories for Advanced Decommissioning Science; Shibaura Institute of Technology*

JAEA-Review 2019-028, 71 Pages, 2020/03

JAEA-Review-2019-028.pdf:6.46MB

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. Among the adopted proposals in FY2018, this report summarizes the research results of the "Development of the Sintering Solidification Method for Spent Zeolite to Long-term Stabilization". The present study aims to develop the sintering solidification method for zeolites (spent zeolites) that adsorbs continuously generated radionuclides such as cesium. The sintering solidification method is able to stabilize adsorbed radionuclides such as cesium in zeolites by adding a glass as a binder to spent zeolite and sintered it. It is expected that the sintering solidification method is significantly reduce the volume of the solidified body compare with the glass solidification method and to form a stable solidified body equivalent to the calcination solidification method. In this project, we planned to select a glass suitable for the sintering solidification method and optimize the sintering temperature, etc. using non-radioactive nuclides (cold tests), and verify it by using radioactive nuclides (hot tests). In FY2018, we investigated the thermal properties of candidate glasses for binder and the effect of heating atmosphere on the sintering solidification method. Irradiated fuel for preparing simulated contaminated water containing radionuclides was selected and the condition of it was observed. In addition, we surveyed existing research results and latest research trends about solidification of zeolite, calcination solidification and so on.

JAEA Reports

Upgrading of recovery method for radioactive microparticles by heavy liquid separation aiming to volume reduction of contaminated soil (Contract research); FY2018 Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development

Collaborative Laboratories for Advanced Decommissioning Science; University of Tsukuba*

JAEA-Review 2019-023, 33 Pages, 2020/01

JAEA-Review-2019-023.pdf:1.97MB

CLADS, JAEA, 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 'Upgrading of Recovery Method for Radioactive Microparticles by Heavy Liquid Separation Aiming to Volume Reduction of Contaminated Soil'. After the accident of the Fukushima Daiichi Nuclear Power Station, radioactive cesium has been heterogeneously distributed in surface soil due to the existence of radioactive microparticles and clay minerals. Therefore, the selective removal of these microparticles will lead to the volume reduction of contaminated soil. The present study examines methods for selectively removing radioactive microparticles from soil. Also, in order to reduce the volume of contaminated soil, we search a possibility to practically apply the separation method that uses the difference in specific gravity of particles (heavy liquid separation method).

JAEA Reports

Annual report for FY2017 on the activities of Department of Decommissioning and Waste Management (April 1, 2017 - March 31, 2018)

Department of Decommissioning and Waste Management

JAEA-Review 2019-011, 91 Pages, 2019/10

JAEA-Review-2019-011.pdf:5.25MB

This report describes the activities of Department of Decommissioning and Waste Management (DDWM) in Nuclear Science Research Institute (NSRI) in the period from April 1, 2017 to March 31, 2018. The report covers organization and missions of DDWM, outline and operation/maintenance of facilities which belong to DDWM, treatment and management of radioactive wastes, decommissioning activities, and related research and development activities which were conducted in DDWM.

Journal Articles

Investigation on the influence of additional protective measures on sheltering effectiveness for internal exposure

Hirouchi, Jun; Takahara, Shogo; Komagamine, Hiroshi*; Munakata, Masahiro

Proceedings of Asian Symposium on Risk Assessment and Management 2019 (ASRAM 2019) (USB Flash Drive), 7 Pages, 2019/09

no abstracts in English

Journal Articles

Sorption parameter setting approaches for radioactive waste disposal considering perturbation effects; Sorption reduction factors for organics

Tachi, Yukio; Ochs, M.*

Progress in Nuclear Science and Technology (Internet), 5, p.229 - 232, 2018/11

Various types of post-accident radioactive waste have been generated from cleanup and decommissioning activities at the Fukushima Daiichi Nuclear Power Plant. For the disposal of these wastes, perturbation effects resulting from co-existing substances (e.g., organic substances, boron, and salts) are needed to be considered. Such co-existing substances may influence on the radionuclide sorption parameters for the safety assessment of the disposal systems. The present study focuses on developing the methodology to quantify sorption parameters by considering such perturbation effects and illustrating example calculations regarding the sorption reduction factors (SRFs) due to the presence of organic ligands (ISA) for cement systems. Three approaches for the derivations of SRFs for cement-Am-ISA case were compared. These options should be applied as a stepwise manner according to the data availability for the perturbation effects resulting from the co-existing substances.

Journal Articles

Investigation of reduction factor of internal exposure for sheltering in Japan

Hirouchi, Jun; Takahara, Shogo; Komagamine, Hiroshi*; Munakata, Masahiro

Proceedings of Asian Symposium on Risk Assessment and Management 2018 (ASRAM 2018) (USB Flash Drive), 8 Pages, 2018/10

no abstracts in English

Journal Articles

Application of Bayesian optimal experimental design to reduce parameter uncertainty in the fracture boundary of a fuel cladding tube under LOCA conditions

Narukawa, Takafumi; Yamaguchi, Akira*; Jang, S.*; Amaya, Masaki

Proceedings of 14th International Conference on Probabilistic Safety Assessment and Management (PSAM-14) (USB Flash Drive), 10 Pages, 2018/09

JAEA Reports

Annual report for FY2016 on the activities of Department of Decommissioning and Waste Management (April 1, 2016 - March 31, 2017)

Department of Decommissioning and Waste Management

JAEA-Review 2018-008, 87 Pages, 2018/07

JAEA-Review-2018-008.pdf:2.67MB

This report describes the activities of Department of Decommissioning and Waste Management (DDWM) in Nuclear Science Research Institute (NSRI) in the period from April 1, 2016 to March 31, 2017. The report covers organization and missions of DDWM, outline and operation/maintenance of facilities which belong to DDWM, treatment and management of radioactive wastes, decommissioning activities, and related research and development activities which were conducted in DDWM.

Journal Articles

Reduction of water content in calcium aluminate cement with/out phosphate modification for alternative cementation technique

Garcia-Lodeiro, I.*; Irisawa, Keita; Jin, F.*; Meguro, Yoshihiro; Kinoshita, Hajime*

Cement and Concrete Research, 109, p.243 - 253, 2018/07

 Times Cited Count:10 Percentile:57.69(Construction & Building Technology)

Journal Articles

Review of reduction factors by buildings for gamma radiation from radiocaesium deposited on the ground due to fallout

Yoshida-Ouchi, Hiroko*; Matsuda, Norihiro; Saito, Kimiaki

Journal of Environmental Radioactivity, 187, p.32 - 39, 2018/07

 Times Cited Count:9 Percentile:22.62(Environmental Sciences)

Journal Articles

Dimension-reduced cross-section adjustment method based on minimum variance unbiased estimation

Yokoyama, Kenji; Yamamoto, Akio*; Kitada, Takanori*

Journal of Nuclear Science and Technology, 55(3), p.319 - 334, 2018/03

 Times Cited Count:5 Percentile:64.98(Nuclear Science & Technology)

A new formulation of the cross-section adjustment methodology with the dimensionality reduction technique has been derived. This new formulation is proposed as the dimension reduced cross-section adjustment method (DRCA). Since the derivation of DRCA is based on the minimum variance unbiased estimation (MVUE), an assumption of normal distribution is not required. The result of DRCA depends on a user-defined matrix that determines the dimension reduced feature subspace. We have examine three variations of DRCA, namely DRCA1, DRCA2, and DRCA3. Mathematical investigation and numerical verification have revealed that DRCA2 is equivalent to the currently widely used cross-section adjustment method. Moreover, DRCA3 is found to be identical to the cross-section adjustment method based on MVUE, which has been proposed in the previous study.

Journal Articles

Identification of penetration path and deposition distribution of radionuclides in houses by experiments and numerical model

Hirouchi, Jun; Takahara, Shogo; Iijima, Masashi; Watanabe, Masatoshi; Munakata, Masahiro

Radiation Physics and Chemistry, 140, p.127 - 131, 2017/11

BB2016-0282.pdf:0.39MB

 Times Cited Count:2 Percentile:28.88(Chemistry, Physical)

Journal Articles

Activities for environmental restoration in Fukushima Environmental Safety Center of JAEA; Miharu-town and Minamisoma-city

Shobu, Nobuhiro

Enerugi Rebyu, 37(10), p.21 - 22, 2017/10

After the Fukushima-Daiichi Nuclear Power Plant Accident, Japan Atomic Energy Agency (JAEA) has been carrying out research and development activities towards the environmental restoration of Fukushima. This paper describes the following representative activities in Fukushima Environmental Safety Center of JAEA, such as the development of environmental monitoring and mapping technologies, the long-term assessment of transport of radio-cesium in the environment of Fukushima, and the technology development for advancing decontamination and volume reduction technologies.

136 (Records 1-20 displayed on this page)