Analysis procedure for halogen elements (bromine and iodine) in powder pellets using a sequential wavelength dispersive X-ray fluorescence spectrometry system at the Tono Geoscience Center, JAEA

Watanabe, Takahiro; Kida, Fukuka; Nara, Fumiko; Yamasaki, Shinichi*; Tsuchiya, Noriyoshi*

JAEA-Testing 2025-006, 52 Pages, 2025/12

JAEA-Testing-2025-006.pdf:6.72MB

Total bromine and iodine concentrations in geological samples serve as valuable geochemical proxies for reconstructing past environmental changes, including relative sea-level changes and marine incursions into an inland area. These halogens have also been used in previous studies to identify past tsunami and storm surge deposits in geological records. Such information contributes to the evaluation of long-term geosphere stability, which is an essential aspect in the geological disposal of high-level radioactive waste. At the Tono Geoscience Center, a sequential wavelength dispersive X-ray fluorescence spectrometry system (WDXRF) has been installed for the major and trace element measurements. However, the application of WDXRF analyses to bromine and iodine has not been established. In this study, we developed analytical methods of total bromine and iodine contents using powdered pellets of standard reference materials. Additionally, evaluation tests of calibration curves were performed using the WDXRF. The validated method was then applied to sediment samples to examine its utility in determination of halogen concentrations.

Research plan on geosphere stability for long-term isolation of radioactive waste (Scientific program for fiscal year 2025)

Asamori, Koichi; Sueoka, Shigeru; Komatsu, Tetsuya; Ogata, Manabu; Uchida, Mao; Nishiyama, Nariaki; Tanaka, Kiriha; Kobayashi, Tomoharu; Mitsuguchi, Takehiro; Murakami, Osamu; et al.

JAEA-Review 2025-035, 29 Pages, 2025/10

JAEA-Review-2025-035.pdf:1.12MB

This report is a plan of research and development (R&D) on geosphere stability for long-term isolation of high-level radioactive waste (HLW) in Japan Atomic Energy Agency (JAEA), in fiscal year 2025. The objectives and contents of this research are described in detail based on the JAEA 4th Medium- and Long-term Plan (fiscal years 2022-2028). In addition, the background of this research is described from the necessity and the significance for site investigation and safety assessment, and the past progress. The plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques.

Bromine and iodine analyses of geological samples by wavelength dispersive X-ray fluorescence spectrometry

Watanabe, Takahiro; Kida, Fukuka; Yamasaki, Shinichi*; Yamagishi, Hiroyuki*; Ochiai, Shinya*; Matsunaka, Tetsuya*; Nara, Fumiko; Tsuchiya, Noriyoshi*

Bunseki Kagaku, 74(10-11), p.611 - 619, 2025/10

https://doi.org/10.2116/bunsekikagaku.74.611

Bromine and iodine contents in geological samples can be used as useful tools to understand various environmental phenomena such as past sea-level changes, geological uplift and subsidence, as well as marine incursion to the inland due to paleo tsunami and storm surges. In this study, we measured bromine and iodine contents in possible standard materials and lake sediment samples using the WDXRF at Tono Geoscience Center and polarizing EDXRF at Tohoku University. We compared both results and confirmed that the WDXRF method for Bromine and iodine content determinations can provide the reliable results.

Whole-rock geochemical analysis of geological samples using wavelength dispersive X-ray fluorescence (WDXRF) spectrometer with glass beads

Kida, Fukuka; Watanabe, Takahiro; Nara, Fumiko

JAEA-Testing 2025-002, 62 Pages, 2025/08

JAEA-Testing-2025-002.pdf:2.97MB

Whole-rock geochemical analysis is one of the basic approaches in petrology or geochemistry to characterize various types of rocks and to investigate their origins, particularly by combining the data on mineral compositions and isotopic ratios. This approach is regarded as an essential technique for providing the fundamental information of the geological sites. X-ray fluorescence (XRF) spectrometry on glass beads is widely used for whole-rock geochemical analysis due to its ability to analyze multiple samples rapidly and efficiently. In this study, we present a quantitative method for analyzing major elements (SiO, TiO, AlO, FeO, MnO, MgO, CaO, NaO, KO, PO) and trace elements (V, Cr, Ni, Rb, Sr, Y, Zr, Nb, Ba, Pb, Th), using wavelength dispersive X-ray fluorescence (WDXRF, Rigaku ZSX Primus II) spectrometer installed in Tono Geoscience Center. We also evaluate the analytical uncertainty through repeated measurements of geochemical standards. Furthermore, this report provides detailed instructions on glass bead sample preparation and the operation of ZSX Primus II, including precaution points, making it a useful reference for XRF analytical procedures.

Linking combustion-derived magnetite and black carbon; Insights from magnetic characterization of PM in downwind East Asia

Nozomu, Tsuchiya*; Ikemori, Fumikazu*; Kawasaki, Kazuo*; Yamada, Rena*; Hata, Mitsuhiko*; Furuuchi, Masami*; Iwamoto, Yoko*; Kaneyasu, Naoki*; Sadanaga, Yasuhiro*; Watanabe, Takahiro; et al.

Environmental Science & Technology, 59(21), p.10400 - 10410, 2025/05

https://doi.org/10.1021/acs.est.4c14187

Black carbon (BC) is a typical primary aerosol emitted from combustion. While its co-existence with iron oxides (FeO) has recently been reported, the extent of bias caused by FeO mixing to the BC observations is largely unknown. To identify the dominant FeO emission sources and associated overestimation of BC, magnetics properties of PM collected at a remote site in East Asia was investigated in combination with detailed isotopic and chemical analyses. Consequently, biomass burning events did not enhance aerosol magnetism as they did for the mass concentration of BC, whereas coal burning events coincided with periods of high magnetization. Therefore, magnetization/BC ratio is proposed as a highly selective indicator for identifying combustion sources (i.e. coal, oil or biomass burning).

Alternative radiocarbon age-depth model from Lake Baikal sediment; Implication for past hydrological changes for last glacial to the Holocene

Nara, Fumiko*; Watanabe, Takahiro; Lougheed, B.*; Obrochta, S.*

Radiocarbon, 66(6), p.1940 - 1957, 2024/12

https://doi.org/10.1017/RDC.2023.63

We present an updated radiocarbon age model using IntCal20 to calibrated new AMS data applied to a Lake Baikal sediment core in south Siberia. Radiocarbon measurements showed that the core extends to 32 cal kaBP. To take into account uncertainties in radiocarbon age and sedimentation depth in the core, a new age-depth modeling routine, undatable, was used in this study. Undatable revealed that the significant changes in the sedimentation rate correspond to global climate events, either warm or cold, which are the Meltwater pulses (MWP) at 19 and 14 cal kaBP and the Last glacial maximum (LGM) at 21-20 cal kaBP. Since the Selenga River accounts for 50 % of the total river inflow to Lake Baikal, we interpret that these changes in sedimentation rate could be signals of significant increase in Selenga River discharge to the lake, which is expected to be affected by global climate change.

Research plan on geosphere stability for long-term isolation of radioactive waste (Scientific program for fiscal year 2024)

Niwa, Masakazu; Shimada, Akiomi; Asamori, Koichi; Sueoka, Shigeru; Komatsu, Tetsuya; Nakajima, Toru; Ogata, Manabu; Uchida, Mao; Nishiyama, Nariaki; Tanaka, Kiriha; et al.

JAEA-Review 2024-035, 29 Pages, 2024/09

JAEA-Review-2024-035.pdf:1.24MB

This report is a plan of research and development (R&D) on geosphere stability for long-term isolation of high-level radioactive waste (HLW) in Japan Atomic Energy Agency (JAEA), in fiscal year 2024. The objectives and contents of this research are described in detail based on the JAEA 4th Medium- and Long-term Plan (fiscal years 2022-2028). In addition, the background of this research is described from the necessity and the significance for site investigation and safety assessment, and the past progress. The plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques.

Holocene paleolimnological changes in Rundvshetta lakes in the Soya Coast region and their paleoenvironmental significance with glacial isostatic adjustment in East Antarctica

Inoue, Genki*; Honda, Eisuke*; Ito, Keisuke*; Kang, I.*; Seto, Koji*; Tani, Yukinori*; Watanabe, Takahiro; Kashima, Kaoru*; Otani, Shuji*; Yamanaka, Toshiro*; et al.

Quaternary Science Reviews, 338, p.108822_1 - 108822_18, 2024/08

https://doi.org/10.1016/j.quascirev.2024.108822

We studied Holocene paleolimnological changes inferred from biomarkers and microscopic observation of microalgae and cyanobacteria in sediment cores from Rundvshetta lakes (Maruwanminami-ike and Maruwan o-ike) in the Soya Coast of East Antarctica, along with sedimentary facies and radiocarbon dating. Coastal marine environment: Maruwanminami-ike (147-72.5 cm, 5,010-2,590 cal BP) and Maruwan-oike (226-47.2 cm, 5,700-3,190 cal BP) were characterized by low biological production with the predominance of diatoms. Transition period of stratified brackish lake environment: Maruwanminami-ike (72.5-65.6 cm, 2,590-2,500 cal BP) and Maruwan-oike (47.2-28.8 cm, 3,190-2,890 cal BP) were characterized by stratified conditions with marine water overlain by freshwater, and a chemocline developed together with an anoxic layer in the bottom of photic zone.

Present status of the JAEA-AMS-TONO (2023FY)

Fujita, Natsuko; Miyake, Masayasu; Matsubara, Akihiro*; Ishii, Masahiro*; Takahashi, Yuto*; Watanabe, Takahiro; Jinno, Satoshi; Nishio, Tomohiro*; Ogawa, Yumi; Kimura, Kenji; et al.

Dai-24-Kai AMS Shimpojiumu Hokokushu (Internet), 3 Pages, 2024/03

The JAEA-AMS-TONO facility at the Tono Geoscience Center, JAEA has three accelerator mass spectrometers. We report the present status of the JAEA-AMS-TONO.

Ion beam induced luminescence measurements of porous silica adsorbents containing europium complexes by argon ion beam irradiation

Nakahara, Masaumi; Watanabe, So; Yuyama, Takahiro*; Ishizaka, Tomohisa*; Yuri, Yosuke*; Ishii, Yasuyuki*; Yamagata, Ryohei*; Yamada, Naoto*; Koka, Masashi*; Kada, Wataru*; et al.

QST-M-47; QST Takasaki Annual Report 2022, P. 64, 2024/03

https://repo.qst.go.jp/records/2000076

An extraction chromatography method has been studied to recover minor actinides from high-level liquid waste. For effective elution of minor actinides in an adsorbent, the structures of complexes are attempted to be evaluated with ion beam induced luminescence. In this study, Eu complexes in the adsorbent were irradiated by Ar ion beam, and the ion beam induced luminescence spectra of Eu complexes were measured to evaluate the structures of Eu complexes.