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Journal Articles

Pressure resistance thickness of disposal containers for spent fuel direct disposal

Sugita, Yutaka; Taniguchi, Naoki; Makino, Hitoshi; Kanamaru, Shinichiro*; Okumura, Taisei*

Nippon 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.

JAEA Reports

Data acquisition for radionuclide sorption on barrier materials for performance assessment of geological disposal of TRU wastes

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$$_{rm d}$$), 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$$_{rm d}$$) 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$$_{rm d}$$ values have been partly reported previously as RAMDA (Radionucldie Migration Datasets) for the performance assessment in the TRU-2 report, these results and addition K$$_{rm d}$$ data are reported with the details of experimental methods and conditions.

Journal Articles

Development of thermodynamic database for performance assessment of geological disposal of high-level radioactive waste and TRU waste

Kitamura, Akira

Nippon Genshiryoku Gakkai-Shi, 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 Reports

Update of JAEA-TDB; Update of thermodynamic data for zirconium and those for isosaccahrinate, tentative selection of thermodynamic data for ternary M$$^{2+}$$-UO$$_{2}$$$$^{2+}$$-CO$$_{3}$$$$^{2-}$$ system and integration with JAEA's thermodynamic database for geochemical calculations

Kitamura, Akira

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.

JAEA Reports

Study of decommissioning cost evaluation technique for nuclear reactor dismantlement; Calculation of decommissioning cost by COSMARD

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.

JAEA Reports

Characterization of the nuclear power plants in decommissioning program and influence evaluation on decommissioning costs

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.

JAEA Reports

Development of elemental components in NDA systems for certifying radioactive wastes with the clearance level

Tsutsumi, Masahiro; Oishi, Tetsuya*; Yamasoto, Kotaro; Yoshida, Makoto

JAERI-Research 2004-021, 43 Pages, 2004/12


We have designed and developed a $$gamma$$ measurement system to certify radioactive wastes below the clearance level. By advancing non-destructive $$gamma$$-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 $$gamma$$-ray measuring instruments (units) with effective improvement of capability against each problem. They are (1) germanium $$gamma$$ spectrometry unit for enhanced peak identification, (2) positioning detection unit for positioning of $$gamma$$ 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.

Journal Articles

High-sensitive detection by direct interrogation of 14 MeV Acc neutrons, 1; Uranium-contained metal matrix in a waste dram

Haruyama, Mitsuo; Takase, Misao*; Tobita, Hiroshi; Mori, Takamasa

Nippon Genshiryoku Gakkai Wabun Rombunshi, 3(2), p.185 - 192, 2004/06

no abstracts in English

JAEA Reports

Reconstruction of CT images by the Bayes-back projection method

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 $$gamma$$-ray CT can widely applied also to, for instance, the Neutron Imaging and the Positron Emission Tomography (PET).

JAEA Reports

Proceedings of the International Symposium NUCEF 2001; Scientific Bases for Criticality Safety, Separation Process and Waste Disposal

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.

JAEA Reports

Development of computer systems for planning and management of reactor decommissioning; A Study on influence of work difficulty factors on project management data and simplification of work breakdown structures (Contract research)

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.

Journal Articles

Implication for long-term behavior of radionuclides in deep underground on the basis of natural analogue phenomena

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.

Journal Articles

PARC process for an advanced PUREX process

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

 Times Cited Count:5 Percentile:60.42

no abstracts in English

Journal Articles

Management of neptunium and technetium in an advanced PUREX process

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

Journal Articles

Effect of activation cross section change on the shallow land burial fraction of low activation materials for fusion reactors

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

Journal Articles

Applicability of insoluble tannin to treatment of waste containing americium

; Usuda, Shigekazu

Journal of Alloys and Compounds, 271-273, p.244 - 247, 1998/00

 Times Cited Count:17 Percentile:28.8(Chemistry, Physical)

no abstracts in English

Journal Articles

The Separation of neptunium and technetium in an advanced purex process

Uchiyama, Gunzo; Asakura, Toshihide; Hotoku, Shinobu; Fujine, Sachio

Solvent Extr. Ion Exch., 16(5), p.1191 - 1213, 1998/00

 Times Cited Count:10 Percentile:48.48(Chemistry, Multidisciplinary)

no abstracts in English

Journal Articles

Development of spent solvent treatment process by submerged combustion technique

Uchiyama, Gunzo; Maeda, Mitsuru; Fujine, Sachio; *; *; *

Journal of Nuclear Science and Technology, 31(3), p.228 - 239, 1994/03

 Times Cited Count:8 Percentile:38.13(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Application of an advanced incineration technique to spent solvent treatment for improving the waste management

Uchiyama, Gunzo; Maeda, Mitsuru; *; Fujine, Sachio; *; *

Proceedings of 4th International Conference on Nuclear Fuel Reprocessing and Waste Management; RECOD '94, Vol.3, 0, p.1 - 15, 1994/00

no abstracts in English

JAEA Reports

Conceptual design study and evaluation of an advanced treatment process applying a submerged combustion technique for spent solvents

Uchiyama, Gunzo; Maeda, Mitsuru; Fujine, Sachio; *; *

JAERI-M 93-213, 204 Pages, 1993/10


no abstracts in English

29 (Records 1-20 displayed on this page)