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Furuno, Akiko; Omori, Ryuta*; Tateoka, Hisanori*; Minakawa, Yuya*; Kurihara, Toshiyuki; Yamamoto, Yoichi; Tomita, Yutaka
Pure and Applied Geophysics, 14 Pages, 2024/00
Times Cited Count：0 Percentile：0.00(Geochemistry & Geophysics)The Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) Okinawa radionuclide monitoring station (JPP37) is located on a hill facing the East China Sea at the center of the main island of Okinawa. It occasionally detects Cs-137, although no nuclear facilities are located on the island. This study focused on the detection of Cs-137 at JPP37 and examined the ratio of simultaneous detections at nearby stations of the International Monitoring System (IMS) of the CTBTO and the relationship with Asian dust from inland East Asia. The detection of Cs-137 in JPP37 from 2020 to 2023, which motivated this study, was high in spring. Among the nine IMS radionuclide stations in East Asia, the detections in Beijing, Lanzhou, and Ulaanbaatar, Mongolia, were also high in spring. This suggested a high association with the detection of Asian dust in East Asia. Thus, we confirmed the detection of Cs-137 at nine nearby IMS stations when Asian dust was observed at any of the sites in Japan. In addition, we observed that the detection rates were high in Takasaki, Beijing, Lanzhou, and Ulaanbaatar. It can be inferred that the Cs-137 observed mainly in spring at the IMS particulate radionuclide stations in the East Asian region around Japan were likely to pick up the effects of global fallout conveyed by Asian dust. Thereafter, we conducted a preliminary source estimation analysis for Asian dust arrival near Japan. Atmospheric dispersion simulations explained the detection of Cs-137 at nearby IMS particulate radionuclide stations, assuming that Cs-137 was emitted from the desert, the source of the Asian dust.
Arai, Yoichi; Watanabe, So; Hasegawa, Kenta; Okamura, Nobuo; Watanabe, Masayuki; Takeda, Keisuke*; Fukumoto, Hiroki*; Ago, Tomohiro*; Hagura, Naoto*; Tsukahara, Takehiko*
Nuclear Instruments and Methods in Physics Research B, 542, p.206 - 213, 2023/09
Times Cited Count：1 Percentile：26.66(Instruments & Instrumentation)Maurer, C.*; Galmarini, S.*; Solazzo, E.*; Ku
mierczyk-Michulec, J.*; Bar
, J.*; Kalinowski, M.*; Schoeppner, M.*; Bourgouin, P.*; Crawford, A.*; Stein, A.*; et al.
Journal of Environmental Radioactivity, 255, p.106968_1 - 106968_27, 2022/12
Times Cited Count：5 Percentile：34.89(Environmental Sciences)After performing multi-model exercises in 2015 and 2016, a comprehensive Xe-133 atmospheric transport modeling challenge was organized in 2019. For evaluation measured samples for the same time frame were gathered from four International Monitoring System stations located in Europe and North America with overall considerable influence of IRE and/or CNL emissions. As a lesion learnt from the 2nd ATM-Challenge participants were prompted to work with controlled and harmonized model set ups to make runs more comparable, but also to increase diversity. Effects of transport errors, not properly characterized remaining emitters and long IMS sampling times (12 to 24 hours) undoubtedly interfere with the effect of high-quality IRE and CNL stack data. An ensemble based on a few arbitrary submissions is good enough to forecast the Xe-133 background at the stations investigated. The effective ensemble size is below five.
aqueous solution system revealed by fluorescence microspectroscopyMiyagawa, Akihisa*; Kusano, Yuka*; Nagatomo, Shigenori*; Sano, Yuichi; Nakatani, Kiyoharu*
Analytical Sciences, 38(7), p.955 - 961, 2022/07
Times Cited Count：1 Percentile：5.86(Chemistry, Analytical)In this study, we reveal an Eu(III) extraction mechanism at the interface between HNO and tributyl phosphate (TBP) solutions using fluorescence microspectroscopy. The mass transfer rate constant at the interface is obtained from the analysis of fluorescence intensity changes during the forward and backward extractions at various HNO and TBP concentrations to investigate the reaction mechanism. This result indicates that one nitrate ion reacts with Eu(III) at the interface, whereas TBP molecules are not involved in the interfacial reaction, which is different from the results obtained using the NaNO solution in our previous study. We demonstrate that the chemical species of Eu(III) complex with nitrate ion and TBP in the aqueous solution play an important role for the extraction mechanism.
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.
Sasaki, Yuji
Bunri Gijutsu, 52(2), p.103 - 107, 2022/03
We develop all-inclusive partitioning method for actinides and fission products in high-level radioactive waste. This process is based on the sequential solvent extraction. In order to recover Cs and Sr for the management by interim storage, crown ether compounds are employed. For the removal of Pd and Mo due to production of a stable vitrified object, methylimino-dioctylacetamide (MIDOA) is taken as an extractant. DGA can extract both actinides and trivalent lanthanides. In order to separate each other, dietylenetriamine-triacetic-diamide (DTBA) for the stripping reagent of MA. For the mutual separation of Am/Cm, DGA and DOODA extraction system is taken into consideration.
Sasaki, Yuji; Kaneko, Masashi; Ban, Yasutoshi; Matsumiya, Masahiko*; Nakase, Masahiko*; Takeshita, Kenji*
Separation Science and Technology, 57(16), p.2543 - 2553, 2022/00
Times Cited Count：4 Percentile：29.12(Chemistry, Multidisciplinary)The mutual separation of actinides (An) from lanthanides (Ln) using the masking agent of DTPA (diethylenetriamine-pentaacetic acid) or DTBA (diethylenetriamine-triacetic acid-bis(diethylacetamide)) in the aqueous phase through DGA extraction, referring TALSPEAK method, is focused. We investigate to obtain the same separation performance using commercially available DTPA on that using DTBA. In this work, we select lactic acid (LA) of pH buffer from 10 organic acids and ethylenediamine (ED) for the pH adjustment. Almost the same D and SF values are obtained among the conditions: TODGA-DTPA-LA-NaOH, TODGA-DTPA-LA-ED, and TODGA-DTBA-LA. The experimental results using batchwise multi-stage extractions show the average yields of Ln (La to Gd) and Am to be 3.73 and 98.1% in the aqueous phase using DGA-DTPA-LA-ED, to be 3.1 and 97.0% using DGA-DTPA-LA-NaOH, and to be 1.61 and 98.7% using DGA-DTBA-LA.
Sasaki, Yuji; Kaneko, Masashi; Matsumiya, Masahiko*; Nakase, Masahiko*; Takeshita, Kenji*
Solvent Extraction and Ion Exchange, 40(6), p.620 - 640, 2022/00
Times Cited Count：2 Percentile：13.50(Chemistry, Multidisciplinary)Owing to the chemical behavior of trivalent lanthanide and actinide ions with similar ionic radii, realizing this separation is still challenging. All lanthanides, Am, and Cm can be extracted using diglycolamide (DGA), and relatively high An/Ln separation efficiencies have been obtained using diethylenetriamine-triacetic-bisamide (DTBA). To improve the previous results as well as the separation conditions, we used organic acids for pH adjustment. The advantages of this modification included low HNO, DTBA concentrations and pH stability owing to the addition of lactic acid. Under these modified conditions, the recovery rates observed were as follows: 97.1% for Nd with the co-existence of 1.59% Am in organic phase, and 98.4% for Am with the co-existence of 2.95% Nd in aqueous phase.
Sasaki, Yuji; Morita, Keisuke; Kitatsuji, Yoshihiro; Ito, Keisuke*; Yoshizuka, Kazuharu*
Solvent Extraction Research and Development, Japan, 28(2), p.121 - 131, 2021/00
Times Cited Count：2 Percentile：9.00(Chemistry, Multidisciplinary)High concentration of Cs is present in high-level radioactive waste. It is well-known that Cs is an alkali element and difficult to extract completely into an organic phase. Crown ether compounds are widely available for Cs extractants; DtBuDB18C6 (di-
-butyl-dibenzo-18crown6), was used in this study. Organic solvents used for the industrial applications, such as 
-dodecane and 1-octanol, have low solubility concerning the compound; other solvents were employed and tested. In this study, ketone-, ether-, and ester-type solvents showed high solubility for DtBuDB18C6 and DtBuDB18C6, when dissolved in ketones and alcohols, exhibited relatively high Cs distribution ratios (
(Cs)), closely to 10.
Manabe, Seiya*; Watanabe, Yukinobu*; Liao, W.*; Hashimoto, Masanori*; Abe, Shinichiro
IEEE Transactions on Nuclear Science, 66(7), p.1398 - 1403, 2019/07
Times Cited Count：10 Percentile：66.83(Engineering, Electrical & Electronic)Cosmic ray-induced soft errors have been recognized as a major threat for electronics used at ground level. Recently, cosmic-ray muon-induced soft errors have received much attention due to the reduction of soft error immunity on SRAMs. In the previous studies, muon-induced soft error rates (SERs) for various technology devices were predicted with only the positive muon irradiation tests and simulation. In this paper, the muon-induced SEU rates for the 65-nm bulk and UTBB-SOI SRAMs are estimated by using the experimental data of both negative and positive muons. The experimental results showed that the negative muon SEU cross sections for the bulk SRAM are significantly larger than those for the UTBB-SOI. Estimation of muon-induced SEU rates at ground level was performed using PHITS with the experimental results. The muon-induced SER on the first floor of the building was estimated to be at most 10% of the neutron-induced SER on the same floor.
Kusaka, Ryoji; Watanabe, Masayuki
Physical Chemistry Chemical Physics, 20(47), p.29588 - 29590, 2018/12
Times Cited Count：20 Percentile：68.11(Chemistry, Physical)Mechanistic understanding of solvent extraction of uranyl ions (UO
) by tributyl phosphate (TBP) will help improve the technology for the treatment and disposal of spent nuclear fuels. So far, it has been believed that uranyl ions in the aqueous phase are adsorbed to a TBP-enriched organic/aqueous interface, form complexes with TBP at the interface, and are extracted into the organic phase. Here we show that uranyl-TBP complex formation does not take place at the interface using vibrational sum frequency generation (VSFG) spectroscopy and propose an alternative extraction mechanism that uranyl nitrate, UO(NO), passes through the interface and forms the uranyl-TBP complex, UO(NO)(TBP), in the organic phase.
Manabe, Seiya*; Watanabe, Yukinobu*; Liao, W.*; Hashimoto, Masanori*; Nakano, Keita*; Sato, Hikaru*; Kin, Tadahiro*; Abe, Shinichiro; Hamada, Koji*; Tampo, Motonobu*; et al.
IEEE Transactions on Nuclear Science, 65(8), p.1742 - 1749, 2018/08
Times Cited Count：13 Percentile：73.85(Engineering, Electrical & Electronic)Recently, the malfunction of microelectronics caused by secondary cosmic-ray muon is concerned as semiconductor devices become sensitive to radiation. In this study, we have performed muon irradiation testing for 65-nm ultra-thin body and thin buried oxide (UTBB-SOI) SRAMs in the Japan Proton Accelerator Research Complex (J-PARC), in order to investigate dependencies of single event upset (SEU) cross section on incident muon momentum and supply voltage. It was found that the SEU cross section by negative muon are approximately two to four times larger than those by positive muon in the momentum range from 35 MeV/c to 39 MeV/c. The supply voltage dependence of muon-induced SEU cross section was measured with the momentum of 38 MeV/c. SEU cross sections decrease with increasing supply voltage, but the decreasing of SEU cross section by negative muon is gentler than that by positive muon. Experimental data of positive and negative muon irradiation with the momentum of 38 MeV/c were analyzed by PHITS. It was clarified that the negative muon capture causes the difference between the SEU cross section by negative muon and that by positive muon.
Amano, Yuki; Watanabe, Koji; Masaki, Tomoo; Tashiro, Shinsuke; Abe, Hitoshi
JAEA-Technology 2016-012, 21 Pages, 2016/06
JAEA-Technology-2016-012.pdf:1.81MB
To contribute to safety evaluation of fire accident in fuel reprocessing plants, solvent extraction behavior of ruthenium, which could form volatile species, was investigated. Distribution ratios of ruthenium at fire accident conditions were obtained by extraction experiments with several solvent composition at different temperature as parameters. In order to investigate release behavior of ruthenium and europium at fire accident, release ratios of ruthenium and europium were also obtained by solvent combustion experiments.
Yamamoto, Yoichi
Isotope News, (736), p.31 - 33, 2015/08
The Takasaki radionuclide (RN) station for the Comprehensive Nuclear-Test-Ban Treaty (CTBT) has been in operation for monitoring of radioactive noble gases (radioxenon) by the Japan Atomic Energy Agency (JAEA) since 2007, first as a test run prior to receiving the certification. The noble gas system in the station was certified by the CTBT Organization (CTBTO) on December 19, 2014. Monitoring of radioxenon is expected to have a particularly valuable role in detection of an underground nuclear test. The Takasaki RN station detected radioxenon isotopes simultaneously with radioactive concentration exceeding normal background range in April, 2013. This abnormal event was identified as being associated with the nuclear test declared by North Korea in February, 2013. Since the Takasaki RN station is located at the east end of Asia, it is receiving widespread international attention as the station for radionuclides dispersed by the westerlies.
Suzuki, Satoshi; Enoeda, Mikio; Hatano, Toshihisa; Hirose, Takanori; Hayashi, Kimio; Tanigawa, Hisashi; Ochiai, Kentaro; Nishitani, Takeo; Tobita, Kenji; Akiba, Masato
Nuclear Fusion, 46(2), p.285 - 290, 2006/02
Times Cited Count：3 Percentile：10.32(Physics, Fluids & Plasmas)This paper presents significant progress in R&D of key technologies on the water-cooled solid breeder blanket for the ITER-TBM in JAERI. By the improvement of heat treatment process for blanket module fabrication, a fine-grained microstructure of F82H, can be obtained by homogenizing it at 1150 
C followed by normalizing at 930 C after the HIP process. Moreover, a promising bonding process for a tungsten armor and an F82H structural material was developed by using a uniaxial hot compression without any artificial compliant layer. Also, it has been confirmed that a fatigue lifetime correlation, which was developed for ITER divertor, can be applicable for F82H first wall mock-up. As for R&D on a breeder material, LiTiO, the effect of compression loads on thermal conductivity of pebble beds has been clarified. JAERI have extensively developed key technologies for ITER-TBM, and now steps up into an engineering R&D stage, where integrated performance of TBM structures will be demonstrated by scalable mock-ups.
Asakura, Toshihide; Hotoku, Shinobu; Ban, Yasutoshi; Matsumura, Masakazu; Morita, Yasuji
Journal of Nuclear and Radiochemical Sciences, 6(3), p.271 - 274, 2005/12
Tc extraction and separation experiments were performed basing on PUREX technique with using spent UO fuel with burn-up of 44 GWd/t. The experimental results were examined with performing calculations by a simulation code ESSCAR (Extraction System Simulation Code for Advanced Reprocessing). It was demonstrated that Tc can be almost quantitatively extracted from a dissolver solution and that Tc can also be almost quantitatively recovered by scrubbing. Further, it was clearly presented from the calculation results of ESSCAR that the extraction mechanism of Tc is dominated by the synergistic effect of Zr and U.
Shinohara, Nobuo; Asano, Yoshie; Hirota, Naoki*; Hokida, Takanori; Inoue, Yoji; Kumata, Masahiro; Nakahara, Yoshinori*; Oda, Tetsuzo*; Uchikoshi, Takako*; Yamamoto, Yoichi
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 3 Pages, 2005/10
Research activities of JAERI related to the CTBT verification regime are presented in the International Conference. The subjects of this presentation are (1) an overview of the CTBT verification regime, (2) construction and operation of the radionuclide monitoring stations of Okinawa (RN37) and Takasaki (RN38) and the certified radionuclide laboratory (RL11), and (3) preparation of the National Data Center at Tokai (JAERI NDC) for radionuclide data. The RN38 station has been certified by the CTBTO/PrepCom and sending the measured data every day. The infrastructures and operational manuals for RN37 and RL11 are now preparing for their operations. The JAERI NDC has experimentally analyzed and evaluated the radionuclide data from all over the world through International Data Center (IDC). As an example of the JAERI NDC works, atmospheric dispersion backtracking system has been developing by using WSPEEDI (Worldwide Version of System for Prediction of Environmental Emergency Dose Information) code to estimate a source location of radionuclide release by nuclear explosion/accident.
Sugikawa, Susumu; Umeda, Miki; Kobayashi, Fuyumi; Nagata, Masanobu*; Dojiri, Shigeru; Amano, Masae*
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 4 Pages, 2005/10
The mineralization of radioactive contaminated organic wastes by mediated electrochemical oxidation process has some attractive features as alternative to incineration process: The process operates safely at low temperatures and ambient pressures. JAERI has been investigated the process since 1996 and confirmed complete mineralization of this organic solvent. In order to greatly improve current efficiency for the oxidation reaction, further experiments were performed under condition of strong mixing of organic solvent and anolyte with an aide of ultrasonic wave. The current efficiencies for the oxidation reaction by ultrasonic agitation between organic solvent and anolyte were twice to that by mechanical agitation. On the basis of these results, two processes, one for destruction of a small amount of TBP/dodecane and the other for destruction of intermediate compounds following alkaline hydrolysis of a large amount of TBP/dodecane, were proposed.
Center for Promotion of Computational Science and Engineering
JAERI-Review 2005-044, 44 Pages, 2005/09
JAERI-Review-2005-044.pdf:8.2MB
This report provides an overview of research and development activities in Center for Promotion of Computational Science and Engineering.
Center for Promotion of Computational Science and Engineering
JAERI-Review 2005-014, 70 Pages, 2005/08
JAERI-Review-2005-014.pdf:3.6MB
This report provides an overview of research and development activities in Center for Promotion of Computational Science and Engineering (CCSE), JAERI, in the fiscal year 2003 (April 1, 2003 - March 31, 2004).
