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Nuclear Science Research Institute, Sector of Nuclear Science Research
JAEA-Review 2023-050, 178 Pages, 2024/03
JAEA-Review-2023-050.pdf:7.06MB
Nuclear Science Research Institute (NSRI) is composed of Planning and Management Department and six departments, namely Department of Operational Safety Administration, Department of Radiation Protection, Engineering Services Department, Department of Research Reactor and Tandem Accelerator, Department of Criticality and Hot Examination Technology and Department of Decommissioning and Waste Management, and each department manages facilities and develops related technologies to achieve the "Medium- to Long- term Plan" successfully and effectively. And, four research centers which are Advanced Science Research Center, Nuclear Science and Engineering Center, Nuclear Engineering Research Collaboration Center and Materials Sciences Research Center, belong to NSRI. In order to contribute the future research and development and to promote management business, this annual report summarizes information on the activities of NSRI of JFY 2021 as well as the activity on research and development carried out by Collaborative Laboratories for Advanced Decommissioning Science, Nuclear Safety Research Center and activities of Nuclear Human Resource Development Center, using facilities of NSRI.
-hexaoctyl nitrilotriacetamide (HONTA) using mixer-settler extractors in a hot cellBan, Yasutoshi; Suzuki, Hideya*; Hotoku, Shinobu; Tsubata, Yasuhiro
Solvent Extraction Research and Development, Japan, 31(1), p.1 - 11, 2024/00
A demonstration test was performed to separate minor actinides (MA; Am and Cm) by -hexaoctyl nitrilotriacetamide (HONTA) as an extractant using mixer-settler extractors installed in a hot cell. A high-level liquid waste containing MA, and rare earths (RE; Y, La, Nd, and Eu) was used as the feed. HONTA diluted to 0.05 mol/dm
in 
-dodecane was fed as the organic phase, and a part of the organic phase was reused without solvent regeneration. HONTA effectively extracted MA, whereas RE were less extractable. Consequently, the Y, La, Nd, and Eu ratios distributed to a RE fraction were 
99.9%, 99.2%, 61.8%, and 81.4%, respectively. The Am and Cm ratios distributed to an MA fraction were 86.8% and 74.7%, respectively, and a substantial amount of MA (0.12 g) was recovered in the MA fraction by the end of the cumulative duration of 40 h.
Tsuchiya, Harufumi; Toh, Yosuke; Ozu, Akira; Furutaka, Kazuyoshi; Kitatani, Fumito; Maeda, Makoto; Komeda, Masao
Journal of Nuclear Science and Technology, 60(11), p.1301 - 1312, 2023/11
Times Cited Count：1 Percentile：72.91(Nuclear Science & Technology)Furutaka, Kazuyoshi; Ozu, Akira; Toh, Yosuke
Nuclear Engineering and Technology, 55(11), p.4002 - 4018, 2023/11
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)Suyama, Kenya; Ueki, Taro; Gunji, Satoshi; Watanabe, Tomoaki; Araki, Shohei; Fukuda, Kodai; Yamane, Yuichi; Izawa, Kazuhiko; Nagaya, Yasunobu; Kikuchi, Takeo; et al.
Proceedings of 12th International Conference on Nuclear Criticality Safety (ICNC2023) (Internet), 6 Pages, 2023/10
To remove and store safely the fuel debris generated by the severe accident of the Fukushima Daiichi Nuclear Power Station in 2011 is one of the most important and challenging topics for decommissioning of the damaged reactors in Fukushima. To validate the adopted method for the evaluation of criticality safety control of the fuel debris through comparison with the experimental data obtained by the criticality experiments, the Nuclear Regulation Authority (NRA) of Japan funds a research and development project which was entrusted to the Nuclear Safety Research Center (NSRC) of Japan Atomic Energy Agency (JAEA) from 2014. In this project, JAEA has been conducting such activities as i) comprehensive computation of the criticality characteristics of the fuel debris and making database (criticality map of the fuel debris), ii) development of new continuous energy Monte Carlo code, iii) evaluation of criticality accident and iv) modification of the critical assembly STACY for the experiments for validation of criticality safety control methodology. After the last ICNC2019, the project has the substantial progress in the modification of STACY which will start officially operation from May 2024 and the development of the Monte Carlo Code "Solomon" suitable for the criticality calculation for materials having spatially random distribution complies with the power spectrum. We present the whole picture of this research and development project and status of each technical topics in the session.
Gunji, Satoshi; Araki, Shohei; Arakaki, Yu; Izawa, Kazuhiko; Suyama, Kenya
Proceedings of 12th International Conference on Nuclear Criticality Safety (ICNC2023) (Internet), 9 Pages, 2023/10
JAEA has been modifying a critical assembly called STACY from a solution system to a light-water moderated heterogeneous system to validate computation results of criticality characteristics of fuel debris generated in the accident at TEPCO's Fukushima Daiichi Nuclear Power Station. To experimentally simulate the composition and characteristics of fuel debris, we will prepare several grid plates which make particular neutron moderation conditions and a number of rod-shaped concrete and stainless-steel materials. Experiments to evaluate fuel debris's criticality characteristics are scheduled using these devices and materials. This series of STACY experiments are planned to measure the reactivity of fuel debris-simulated samples, measure the critical mass of core configurations containing structural materials such as concrete and stainless steels, and the change in critical mass when their arrangement becomes non-uniform. Furthermore, two divided cores experiments are scheduled that statically simulate fuel debris falling, and also scheduled that subcriticality measurement experiments with partially different neutron moderation conditions. The experimental plans have been considered taking into account some experimental constraints. This paper shows the schedule of these experiments, as well as the computation results of the optimized core configurations and expected results for each experiment.
Suzuki, Hideya*; Ban, Yasutoshi
Analytical Sciences, 39(8), p.1341 - 1348, 2023/08
Times Cited Count：2 Percentile：76.52(Chemistry, Analytical)The Japan Atomic Energy Agency (JAEA) has proposed the Solvent Extraction from Liquid waste using Extractants of CHON-type for Transmutation (SELECT) process by solvent extraction as a new separation technology to recover minor actinides (MA) from high-level liquid waste (HLLW) produced by spent fuel reprocessing. The MA separation in the SELECT process comprises the batch recovery of MA and rare earths (RE) from HLLW, MA/RE separation, and Am/Cm separation. Three highly practical extractants are used in the MA separation. Furthermore, this flow configuration facilitates the preparation of nitric acid concentrations in the aqueous phase. However, the separation factor between Cm and Nd in the MA/RE separation is small (
= 2.5), requiring many extraction stages for continuous extraction in a mixer-settler. Therefore, this study investigated the separation of only Am from an aqueous nitric acid solution containing MA (Am and Cm) and RE using an organic phase mixed with two extractants alkyl diamideamine with 2-ethylhexyl alkyl chains (ADAAM(EH)) and hexa-n-octylnitrilotriacetamide (HONTA) used in the SELECT process. Under high-concentration nitric acid conditions, Am and La, Ce, Pr, Nd (light lanthanides) were extracted in the ADAAM(EH) + HONTA mixed solvent, whereas Cm, medium, and heavy lanthanides, and Y were partitioned in the aqueous phase. Subsequently, only light lanthanides could be back extracted from the ADAAM(EH) + HONTA mixture solvent containing Am and light lanthanides in low nitric acid concentrations. Furthermore, Am could be easily stripped with 0.2 M or 5 M nitric acid. This method does not require the mutual separation of Cm and Nd, which have low separation factors. Am can be efficiently separated by one extraction and two back-extractions, reducing the number of steps in the SELECT process.
Ohira, Saki; Abe, Takeyasu; Iida, Yoshihisa
Radiochimica Acta, 111(7), p.525 - 531, 2023/07
Times Cited Count：0 Percentile：0.01(Chemistry, Inorganic & Nuclear)The solubility of 
Nb in calcium alkaline solutions is one of the important parameters in safety assessment of intermediate-depth disposal which are assumed to use cementitious materials. Nb solubility and solubility-limiting solid phases of Nb in these systems remain unclear. The oversaturation solubility experiments were performed systematically in the 0.001-0.1 M CaCl
solutions under alkali conditions, and the characterization of precipitated solid phase controlling Nb solubility was conducted. The negative dependence of Nb solubilities on pH and Ca concentration was observed in solubility experiments, the molar ratio of Nb to Ca of precipitated solid phase was 0.66. The pH and Ca dependence of Nb solubilities was reproduced by the reaction with Nb aqueous species Nb(OH)
and Ca-Nb oxide with the molar ratio of Nb to Ca 0.66, e.g., Ca
NbO
(am).
Nuclear Science Research Institute, Sector of Nuclear Science Research
JAEA-Review 2023-009, 165 Pages, 2023/06
JAEA-Review-2023-009.pdf:5.76MB
Nuclear Science Research Institute (NSRI) is composed of Planning and Management Department and six departments, namely Department of Operational Safety Administration, Department of Radiation Protection, Engineering Services Department, Department of Research Reactor and Tandem Accelerator, Department of Criticality and Hot Examination Technology and Department of Decommissioning and Waste Management, and each department manages facilities and develops related technologies to achieve the "Medium- to Long-term Plan" successfully and effectively. And, four research centers which are Advanced Science Research Center, Nuclear Science and Engineering Center, Nuclear Engineering Research Collaboration Center and Materials Sciences Research Center, belong to NSRI. In order to contribute the future research and development and to promote management business, this annual report summarizes information on the activities of NSRI of JFY 2020 as well as the activity on research and development carried out by Collaborative Laboratories for Advanced Decommissioning Science, Nuclear Safety Research Center and activities of Nuclear Human Resource Development Center, using facilities of NSRI.
Nuclear Science Research Institute, Sector of Nuclear Science Research
JAEA-Review 2023-006, 153 Pages, 2023/06
JAEA-Review-2023-006.pdf:5.74MB
Nuclear Science Research Institute (NSRI) is composed of Planning and Management Department and six departments, namely Department of Operational Safety Administration, Department of Radiation Protection, Engineering Services Department, Department of Research Reactor and Tandem Accelerator, Department of Criticality and Hot Examination Technology and Department of Decommissioning and Waste Management, and each department manages facilities and develops related technologies to achieve the "Medium- to Long term Plan" successfully and effectively. And, four research centers which are Advanced Science Research Center, Nuclear Science and Engineering Center, Nuclear Engineering Research Collaboration Center and Materials Sciences Research Center, are transferred to NSRI newly. In order to contribute the future research and development and to promote management business, this annual report summarizes information on the activities of NSRI of JFY 2019 as well as the activity on research and development carried out by Collaborative Laboratories for Advanced Decommissioning Science, Nuclear Safety Research Center and activities of Nuclear Human Resource Development Center, using facilities of NSRI.
(M = Gd, Np) by the reaction of MN with Pd and chlorination of MPd using cadmium chlorideHayashi, Hirokazu; Shibata, Hiroki; Sato, Takumi; Otobe, Haruyoshi
Journal of Radioanalytical and Nuclear Chemistry, 332(2), p.503 - 510, 2023/02
Times Cited Count：0 Percentile：0.01(Chemistry, Analytical)The formation of MPd (M = Gd, Np) by the reaction of MN with Pd at 1323 K in Ar gas flow was observed. Cubic AuCu
-type GdPd
(
= 0.4081 
0.0001 nm) and NpPd ( = 0.4081 0.0001 nm) were identified, respectively. The product obtained from the reaction of NpN with Pd contained additional phases including the hexagonal TiNi-type NpPd. Chlorination of the MPd (M = Gd, Np) samples was accomplished by the solid-state reaction using cadmium chloride at 673 K in a dynamic vacuum. Pd-rich solid solution phase saturated with Cd and an intermetallic compound PdCd were obtained as by-products of MCl formation.
Ohira, Saki; Iida, Yoshihisa
Proceedings of Waste Management Symposia 2023 (WM2023) (Internet), 10 Pages, 2023/02
The sorption distribution coefficient (
d) of niobium-94 (Nb-94) on minerals is one of the important parameters in safety assessment of radioactive waste disposal. In a previous study, the d values of Nb under alkali condition in the presence of Ca, were two orders of magnitude higher than those in the presence of Na. In this study, Nb sorption experiments were performed to reexamine the effect of Ca on Nb sorption on clay minerals, and blank tests were performed to check for precipitation formation. The results showed that the Nb sorption onto montmorillonite and illite, did not depend on the Ca concentration, and d values obtained in the presence of Ca were the same as those in the absence of Ca. A sorption model assuming sorption by complexation on the mineral surface was developed and then calculated using the geochemical calculation code. The model with the surface species X_ONb(OH) and X_ONb(OH)
represented trends in the data obtained.
Ikeuchi, Hirotomo; Koyama, Shinichi; Osaka, Masahiko; Takano, Masahide; Nakamura, Satoshi; Onozawa, Atsushi; Sasaki, Shinji; Onishi, Takashi; Maeda, Koji; Kirishima, Akira*; et al.
JAEA-Technology 2022-021, 224 Pages, 2022/10
JAEA-Technology-2022-021.pdf:12.32MB
A set of technology, including acid dissolving, has to be established for the analysis of content of elements/nuclides in the fuel debris samples. In this project, a blind test was performed for the purpose of clarifying the current level of analytical accuracy and establishing the alternative methods in case that the insoluble residue remains. Overall composition of the simulated fuel debris (homogenized powder having a specific composition) were quantitatively determined in the four analytical institutions in Japan by using their own dissolving and analytical techniques. The merit and drawback for each technique were then evaluated, based on which a tentative flow of the analyses of fuel debris was constructed.
Komeda, Masao; Toh, Yosuke
Applied Radiation and Isotopes, 188, p.110391_1 - 110391_6, 2022/10
Times Cited Count：0 Percentile：0.01(Chemistry, Inorganic & Nuclear)Sano, Yuichi; Sakamoto, Atsushi; Miyazaki, Yasunori; Watanabe, So; Morita, Keisuke; Emori, Tatsuya; Ban, Yasutoshi; Arai, Tsuyoshi*; Nakatani, Kiyoharu*; Matsuura, Haruaki*; et al.
Proceedings of International Conference on Nuclear Fuel Cycle; Sustainable Energy Beyond the Pandemic (GLOBAL 2022) (Internet), 4 Pages, 2022/07
We developed a hybrid MA(III) recovery process combining MA(III)+Ln(III) co-recovery flowsheet by solvent extraction with TBP and MA(III)/Ln(III) separation flowsheet by simulated moving bed chromatography using HONTA impregnated adsorbents with large particle size porous silica support.
Nuclear Science Research Institute, Sector of Nuclear Science Research
JAEA-Review 2021-072, 141 Pages, 2022/03
JAEA-Review-2021-072.pdf:7.14MB
Nuclear Science Research Institute (NSRI) is composed of Planning and Management Department and six departments, namely Department of Operational Safety Administration, Department of Radiation Protection, Engineering Services Department, Department of Research Reactor and Tandem Accelerator, Department of Criticality and Hot Examination Technology and Department of Decommissioning and Waste Management, and each department manages facilities and develops related technologies to achieve the "Medium- to Long-term Plan" successfully and effectively. In order to contribute the future research and development and to promote management business, this annual report summarizes information on the activities of NSRI of JFY 2018 as well as the activity on research and development carried out by Collaborative Laboratories for Advanced Decommissioning Science, Nuclear Safety Research Center, Advanced Science Research Center, Nuclear Science and Engineering Center and Materials Science Research Center, and activities of Nuclear Human Resource Development Center, using facilities of NSRI.
Nuclear Science Research Institute, Sector of Nuclear Science Research
JAEA-Review 2021-067, 135 Pages, 2022/03
JAEA-Review-2021-067.pdf:7.31MB
Nuclear Science Research Institute (NSRI) is composed of Planning and Coordination Office and six departments, namely Department of Operational Safety Administration, Department of Radiation Protection, Engineering Services Department, Department of Research Reactor and Tandem Accelerator, Department of Fukushima Technology Development and Department of Decommissioning and Waste Management, and each departments manage facilities and develop related technologies to achieve the "Middle-term Plan" successfully and effectively. In order to contribute the future research and development and to promote management business, this annual report summarizes information on the activities of NSRI of JFY 2017 as well as the activity on research and development carried out by the Nuclear Safety Research Center, Advanced Science Research Center, Nuclear Science and Engineering Center, Materials Sciences Research Center, and development activities of Nuclear Human Resources Development Center, using facilities of NSRI.
Shimada, Asako; Taniguchi, Yoshinori; Kakiuchi, Kazuo; Ohira, Saki; Iida, Yoshihisa; Sugiyama, Tomoyuki; Amaya, Masaki; Maruyama, Yu
Scientific Reports (Internet), 12(1), p.2086_1 - 2086_11, 2022/02
Times Cited Count：1 Percentile：31.61(Multidisciplinary Sciences)no abstracts in English
Nuclear Science Research Institute
JAEA-Review 2021-006, 248 Pages, 2021/12
JAEA-Review-2021-006.pdf:7.17MB
Nuclear Science Research Institute (NSRI) is composed of Planning and Coordination Office and six departments, namely Department of Operational Safety Administration, Department of Radiation Protection, Engineering Services Department, Department of Research Reactor and Tandem Accelerator, Department of Fukushima Technology Development and Department of Decommissioning and Waste Management, and each department manages facilities and develops related technologies to achieve the "Middle and long-term Plan" successfully and effectively. In order to contribute the future research and development and to promote management business, this annual report summarizes information on the activities of NSRI of JFY 2015 and 2016 as well as the activity on research and development carried out by Nuclear Safety Research Center, Advanced Science Research Center, Nuclear Science and Engineering Center, Material Science Research Center, and development activities of Nuclear Human Resources Development Center, using facilities of NSRI.
Inagawa, Jun; Kitatsuji, Yoshihiro; Otobe, Haruyoshi; Nakada, Masami; Takano, Masahide; Akie, Hiroshi; Shimizu, Osamu; Komuro, Michiyasu; Oura, Hirofumi*; Nagai, Isao*; et al.
JAEA-Technology 2021-001, 144 Pages, 2021/08
JAEA-Technology-2021-001.pdf:12.98MB
Plutonium Research Building No.1 (Pu1) was qualified as a facility to decommission, and preparatory operations for decommission were worked by the research groups users and the facility managers of Pu1. The operation of transportation of whole nuclear materials in Pu1 to Back-end Cycle Key Element Research Facility (BECKY) completed at Dec. 2020. In the operation included evaluation of criticality safety for changing permission of the license for use nuclear fuel materials in BECKY, cask of the transportation, the registration request of the cask at the institute, the test transportation, formulation of plan for whole nuclear materials transportation, and the main transportation. This report circumstantially shows all of those process to help prospective decommission.
