Yamashita, Kiyoto; Yokoyama, Aya*; Takagai, Yoshitaka*; Maki, Shota; Yokosuka, Kazuhiro; Fukui, Masahiro; Iemura, Keisuke
JAEA-Technology 2022-020, 106 Pages, 2022/10
Radioactive solid wastes generated by Fukushima Daiichi Nuclear Power Station disaster may contain high levels of salt from the tsunami and seawater deliberately released into the area. It is assumed that polyvinyl chloride (PVC) products may be used for decommissioning work and for containment of radioactive wastes in the future. Among the method of handling them, incineration is one method that needs to be investigated as it is good method for reduction and stabilization of wastes. But in order to dispose of Trans-Uranic (TRU) solid waste containing chlorides, it is necessary to select the structure and materials of the facility based on the information such as the movement of nuclides and chlorides in the waste gas treating system and the corrosion of equipment due to chlorides. Therefore, we decided to get various data necessary to design a study of the incineration facilities. And we decided to examine the transfer behavior of chlorides to the waste gas treatment system, the corrosion-resistance of materials in the incineration facilities, and the distribution survey of plutonium in them obtained using the Plutonium-contaminated Waste Treatment Facility (PWTF), Nuclear Fuel Cycle Engineering Laboratories, which is a unique incinerating facility in Japan. This report describes the transfer behavior of chlorides in the waste gas treatment system, the evaluation of corrosion-resistance materials and the distribution survey of plutonium in the incineration facilities obtained by these tests using the Plutonium-contaminated Waste Treatment Facility, Nuclear Fuel Cycle Engineering Laboratories.
Collaborative Laboratories for Advanced Decommissioning Science; Hokkaido University*
JAEA-Review 2021-070, 98 Pages, 2022/03
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 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 "Study on rational treatment/disposal of contaminated concrete waste considering leaching alteration" conducted in FY2020. The present study aims to understand migration behaviors of radionuclides in relation to the properties of concrete materials altered due to leaching, to develop a model to simulate the migration behaviors based on the experimental findings, and to analyze waste management scenarios for radioactive concrete. The focus of the study is the underground concrete structures of Fukushima Daiichi Nuclear Power Station, which is in contact with contaminated water.
JAEA-Data/Code 2020-020, 164 Pages, 2021/03
Part of JAEA's Thermodynamic Database (JAEA-TDB) for solubility and speciation of radionuclides (JAEA-TDB-RN) for performance assessment of geological disposal of high-level radioactive and TRU wastes has been updated with subsuming the database for geochemical calculations (JAEA-TDB-GC). This report has focused to update JAEA-TDB-RN after selecting change in standard Gibbs free energy of formation (), change in standard enthalpy change of formation (), standard molar entropy () and, heat capacity (), change in standard Gibbs free energy of reaction (), change in standard enthalpy change of reaction () and standard entropy change of reaction () as well as logarithm of equilibrium constant (log) at standard state. The extent of selection of these thermodynamic data enables to evaluate solubility and speciation of radionuclides at temperatures other than 298.15 K. Furthermore, the latest thermodynamic data for iron which have been critically reviewed, selected and compiled by the Nuclear Energy Agency within Organisation for Economic Co-operation and Development (OECD/NEA) have been accepted. Most of previously selected log have been refined to confirm internal consistency with JAEA-TDB-GC. Text files of the updated JAEA-TDB have been provided for geochemical calculation programs of PHREEQC and Geochemist's Workbench.
Kitamura, Akira; Yoshida, Yasushi*; Goto, Takahiro*; Shibutani, Sanae*
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 27(2), p.58 - 71, 2020/12
Evaluation and estimation of solubility values are required for a performance assessment of geological disposal of high-level radioactive and TRU wastes. Selection of solubility-limiting solid phases (SSPs) that control the solubility of radionuclides is necessary for the evaluation and estimation of solubility values. The authors have developed a methodology for selection of the SSP through a calculation of saturation indices (SIs) using thermodynamic database to show a transparent procedure for the selection. Literature survey should be performed to confirm decision of the SSP from candidate SSPs which generally have larger SIs from realistic point of view for precipitation and solubility control. The authors have selected the SSPs for the elements of interest for the latest Japanese performance assessment in bentonite and cement porewaters after grouping various water compositions.
Sugita, Yutaka; Taniguchi, Naoki; Makino, Hitoshi; Kanamaru, Shinichiro*; Okumura, Taisei*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 19(3), p.121 - 135, 2020/09
A series of structural analysis of disposal containers for direct disposal of spent fuel was carried out to provide preliminary estimates of the required pressure resistance thickness of the disposal container. Disposal containers were designed to contain either 2, 3 or 4 spent fuel assemblies in linear, triangular or square arrangements, respectively. The required pressure resistance thickness was evaluated using separation distance of the housing space for each spent fuel assembly as a key model parameter to obtain the required thickness of the body and then the lid of the disposal container. This work also provides additional analytical technical knowledge, such as the validity of the setting of the stress evaluation line and the effect of the model length on the analysis. These can then be referred to and used again in the future as a basis for conducting similar evaluations under different conditions or proceeding with more detailed evaluations.
Tachi, Yukio; Suyama, Tadahiro*; Mihara, Morihiro
JAEA-Data/Code 2019-021, 101 Pages, 2020/03
Sorption of radionuclides in cement and bentonite as engineered barrier materials, and rocks as natural barrier is the one of key processes in the performance assessment of geological disposal of TRU and high-level waste. The magnitude of sorption, expressed normally by a distribution coefficient (K), needs to be measured and determined taking into account the properties of barrier materials and geochemical conditions and associated uncertainty in the performance assessment. The basic concept for TRU waste disposal contains cementitious materials as an engineered barrier materials, in addition to bentonite and rock. It is therefore needed to consider the effects of the cement degradation and co-existing substances such as nitrates on radionuclide sorption. This report focused on data acquisition of distribution coefficient (K) by batch sorption experiments for the systems coupling barrier material-chemical condition-radionuclides that are needed to consider for the performance assessment of geological disposal of TRU waste. The barrier materials considered are ordinary Portland cement (OPC), degraded OPC and tuff rock. The chemical conditions are distilled water and synthetic seawater equilibrated with OPC and those containing nitrates and ammonium salts, etc. The radionuclides considered are organic carbon, inorganic carbon, Cl, I, Cs, Ni, Se, Sr, Sn, Nb, Am and Th. Although K values have been partly reported previously as RAMDA (Radionuclide Migration Datasets) for the performance assessment in the TRU-2 report, these results and addition K data are reported with the details of experimental methods and conditions.
Nihon Genshiryoku Gakkai-Shi ATOMO, 62(1), p.23 - 28, 2020/01
Thermodynamic databases (TDBs) for performance assessment of geological disposal of high-level waste and TRU waste have been developed to predict solubility and speciation of radionuclides in groundwater in some countries including Japan. The present manuscript briefly describes current status of development of the TDB organized by the Nuclear Energy Agency within the Organisation of Economic Co-operation and Development (OECD/NEA) and the TDBs in some countries including Japan.
JAEA-Data/Code 2018-018, 103 Pages, 2019/03
The latest available thermodynamic data were critically reviewed and the selected values were included into the JAEA-TDB for performance assessment of geological disposal of high-level radioactive and TRU wastes. This critical review specifically addressed thermodynamic data for (1) a zirconium-hydroxide system through comparison of thermodynamic data selected by the Nuclear Energy Agency within the Organisation for Economic Co-operation and Development (OECD/NEA), (2) complexation of metal ions with isosaccharinic acid based on the latest review papers. Furthermore, the author performed (3) tentative selection of thermodynamic data on ternary complexes among alkaline-earth metal, uranyl and carbonate ions, and (4) integration with the latest version of JAEA's thermodynamic database for geochemical calculations. The internal consistency of the selected data was checked by the author. Text files of the updated and integrated thermodynamic database have been prepared for geochemical calculation programs of PHREEQC and Geochemist's Workbench.
Oshima, Soichiro; Shiraishi, Kunio; Shimada, Taro; Sukegawa, Takenori; Yanagihara, Satoshi
JAERI-Tech 2005-046, 46 Pages, 2005/09
A model for estimating decommissioning costs consisting of labor cost, device cost and expense, was developed for items which OECD/NEA had standardized, and was installed into the computer system for planning and management of reactor decommissioning (COSMARD). Input data files and databases for the decommissioning of JPDR were prepared, and the decommissioning cost was calculated with COSMARD. In addition, the decommissioning cost for a large scale BWR power plant was also calculated on the assumption of the advantage of scale. The calculations have shown that it is useful and efficient for studying the decommissioning costs for nuclear reactors to apply the COSMARD with database for cost estimation to the decommissioning cost calculation.
Mizukoshi, Seiji; Oshima, Soichiro; Shimada, Taro
JAERI-Tech 2005-011, 122 Pages, 2005/03
The radiological and physical characteristic on decommissioning, such as component and structure weights and radioactivity of the 1.1 MWe class reference nuclear power plants summarized in the NUREG reports of the US NRC were classified,arranged and compared with the domestic commercial nuclear power plants and JPDR from a view point of dismantling plan and waste management for decommissioning. As the results, it was found that the radioactive component and structure weights was about 28,000ton、and non-radioactive structure weights was about 124,000ton less than the domestic commercial BWR. And it was found that this differences has mainly influenced dismantling costs for decommissioning. Farther, it was found that the concrete element composition rates of B, Ni, Nb and so were differerence of one or more figures btween the reference nuclear power plants and the domestic commercial PWR or JPDR.Also,it was found that the this difference became about two or three times by radioactivity concentration and has mainly influenced transport and disposal costs for decommissioning.
Tsutsumi, Masahiro; Oishi, Tetsuya*; Yamasoto, Kotaro; Yoshida, Makoto
JAERI-Research 2004-021, 43 Pages, 2004/12
We have designed and developed a measurement system to certify radioactive wastes below the clearance level. By advancing non-destructive -ray assay technology, it aims at quantitative determination of radionuclides contained in 200 litter drum/container wastes. Unlike the waste from a nuclear power plant, you have to assume that the waste originating from radioisotope usage and nuclear research laboratory have a variety of contents and a complex mixture of radionuclides, and furthermore the uniformity of activity concentration is unknown. To cope with the problems, we have developed the -ray measuring instruments (units) with effective improvement of capability against each problem. They are (1) germanium spectrometry unit for enhanced peak identification, (2) positioning detection unit for positioning of interactions and (3)high-efficiency detection unit for separation of low-energy component. This report summarizes the direction of the clearance level measuring system and the three developed measuring units with their performances.
Haruyama, Mitsuo; Takase, Misao*; Tobita, Hiroshi; Mori, Takamasa
Nihon Genshiryoku Gakkai Wabun Rombunshi, 3(2), p.185 - 192, 2004/06
no abstracts in English
Haruyama, Mitsuo; Takase, Misao*; Iwasaki, Shin*; Tobita, Hiroshi
JAERI-Research 2002-022, 91 Pages, 2002/12
In the course of research on quantitative assay of non-destructive measurement of radioactive waste, the authors have developed a unique program based on the Bayesian theory for reconstruction of transmission computed tomography (TCT) image. The reconstruction of cross-section images in the CT technology usually employs the Filtered Back Projection method. The new imaging reconstruction program reported here is based on the Bayesian Back Projection method, and it has a function of iterative improvement images by every step of measurement. Namely, this method has the capability of prompt display of a cross-section image corresponding to each angled projection data from every measurement. Hence, it is possible to observe an improved cross-section view by reflecting each projection data in almost real time. The present reconstruction program developed here for the -ray CT can widely applied also to, for instance, the Neutron Imaging and the Positron Emission Tomography (PET).
NUCEF 2001 Symposium Working Group
JAERI-Conf 2002-004, 714 Pages, 2002/03
This volume contains 94 papers presented at the 3rd NUCEF International Symposium NUCEF 2001 held on October 31 - November 2, 2001, in Tokai, Japan, following the 1st symposium NUCEF'95 (Proceedings: JAERI-Conf 96-003) and the 2nd symposium NUCEF'98 (Proceedings: JAERI-Conf 99-004). The theme of this symposium was " Scientific Basis for Criticality Safety, Separation Process and Waste Disposal". The papers were presented in oral and poster sessions on following research fields: (1) Separation Process, (2) TRU Chemistry, (3) Radioactive Waste Disposal, (4) Criticality Safety.
Oshima, Soichiro; Sukegawa, Takenori; Shiraishi, Kunio; Yanagihara, Satoshi
JAERI-Tech 2001-086, 83 Pages, 2001/12
Project management data on dismantling the Japan Power Demonstration Reactor (JPDR) was calculated using the Code System for Planning and Management of Reactor Decommissioning (COSMARD), and then its validity was studied by comparing the calculation results with actual data. In addition, work breakdown structure models and database were modified to meet an evaluation with changing work difficulty of preparation and cleanup activities, and calculations were further conducted to analyze feasibility by changing various conditions on cutting and conditioning activities. As the results, COSMARD was verified to be useful by confirming calculation capability on reflection of actual work conditions and relatively good agreement between actual data and calculations. Moreover, it was cleared that main parameters such as work difficulty of preparation and cleanup activities and the cutting speed in demolition work could affect to manpower within 30% in each calculations.
Nagano, Tetsushi; Nakayama, Shinichi
Genshiryoku Bakkuendo Kenkyu, 8(1), p.81 - 88, 2001/09
Japan Atomic Energy Research Institute has studied to predict the long-term migration of radionuclides in geosphere in terms of radioactive waste disposal. The research activity was introduced to junior high and high school students at a seminar of the Mineralogical Society of Japan. The content of the lecture was summarized.
Uchiyama, Gunzo; Mineo, Hideaki; Hotoku, Shinobu; Asakura, Toshihide; Kamei, Kazushige; Watanabe, Makio; Nakano, Yuji*; Kimura, Shigeru; Fujine, Sachio
Progress in Nuclear Energy, 37(1-4), p.151 - 156, 2000/12
no abstracts in English
Uchiyama, Gunzo; Hotoku, Shinobu; Watanabe, Makio; Kamei, Kazushige; Mineo, Hideaki; Nakano, Yuji*; Kimura, Shigeru; Asakura, Toshihide; Fujine, Sachio
Proceedings of 7th International Conference on Radioactive Waste Management and Environmental Remediation (ICEM '99) (CD-ROM), p.5 - 0, 1999/00
no abstracts in English
Seki, Yasushi; Aoki, Isao; Ueda, Shuzo; Nishio, Satoshi; Kurihara, Ryoichi; Tabara, Takashi*
Fusion Technology, 34(3), p.353 - 357, 1998/11
no abstracts in English
; Usuda, Shigekazu
Journal of Alloys and Compounds, 271-273, p.244 - 247, 1998/00
no abstracts in English