Development of a quantification method for Zr isotopes in solid samples by LA-ICP-MS for rapid analysis of Zr-93 in high-level radioactive wastes

Morii, Shiori; Yomogida, Takumi; Asai, Shiho*; Ouchi, Kazuki; Oka, Toshitaka; Kitatsuji, Yoshihiro

Bunseki Kagaku, 72(10.11), p.441 - 448, 2023/10

https://doi.org/10.2116/bunsekikagaku.72.441

Rapid analytical method for the determination of Zr-93 in radioactive wastes has been developed. Laser ablation (LA)-ICP-MS was applied to the analysis of Zr isotopes in simulated high-level radioactive waste (HLW). Sample preparation time was dramatically reduced by using a DGA resin as the adsorbent for Zr. Direct quantification of Zr isotopes in this resin sample was carried out by LA-ICP-MS. Laser settings were optimized to obtain a reliable isotope ratio of the sample by LA-ICP-MS. Quantification of Zr isotopes in the simulated HLW solution by isotope dilution mass spectrometry (IDMS) was examined. The amount of Zr-90 in the sample obtained by IDMS corresponded to a value calculated from the given concentration of Zr in the sample within uncertainty. Thus, this method can be applied for the quantification of Zr-93 in radioactive wastes.

Outlining zircon growth in a granitic pluton using 3D cathodoluminescence patterns, U-Pb age, titanium concentration, and Th/U; Implications for the magma chamber process of Okueyama granite, Kyushu, Japan

Yuguchi, Takashi*; Ito, Daichi*; Yokoyama, Tatsunori; Sakata, Shuhei*; Suzuki, Satoshi*; Ogita, Yasuhiro; Yagi, Koshi*; Imura, Takumi*; Motai, Satoko*; Ono, Takeshi*

Lithos, 440-441, p.107026_1 - 107026_14, 2023/03

https://doi.org/10.1016/j.lithos.2023.107026

We propose a new method for elucidating zircon growth in granitic plutons, based on variations in three-dimensional 3D cathodoluminescence (CL) patterns, U-Pb ages, titanium concentration, and Th/U ratios. We focused on the zircon growth processes in the Okueyama granite (OKG) in central Kyushu, Japan, to obtain interpretations of magma chamber processes that result in the formation of granitic plutons. The OKG consists of three lithofacies: biotite granite (BG), hornblende granite (HG), and hornblende granodiorite (HGD). To determine the 3D internal structure and growth pattern of a zircon crystal, we performed CL observations for multi-sections of the samples. Simultaneously, we also determined the zircon U-Pb age and titanium concentration of the center sections of the samples. The 3D distribution of the oscillatory zoning can be used to determine the crystal nucleus. The simultaneous determination of zircon U-Pb ages and Ti concentrations of the granite samples indicates the time-temperature (t-T) history of granitic magma before its solidification. The t-T histories of the BG, HG, and HGD represented similar cooling behaviors within the magma chamber: rapid cooling from the zircon crystallization temperature to the closure temperature of the biotite K-Ar system between 16 Ma and 10 Ma. The variations in the Th/U ratios against temperature also demonstrate a different trend at the boundary of approximately 670 C. Fractional crystallization in the magma chamber progressed significantly at temperatures above 670 C; below 670 C, crystallization progressed slowly, indicating only minimal changes in the magma composition. The variations in the Th/U ratio against temperature in the BG, HG, and HGD portrayed common tendencies, indicating the same behavior in the progression of fractional crystallization among the three lithofacies, which in turn, represented the same behavior within the entire magma chamber.

Analytical method for chemical compositions of volcanic glasses in Tono Geoscience Center; Quantitative measurements of Major Elements by using EPMA and Minor Elements by LA-ICP-MS

Kagami, Saya; Yokoyama, Tatsunori; Umeda, Koji*

JAEA-Testing 2021-001, 49 Pages, 2021/08

JAEA-Testing-2021-001.pdf:3.86MB

To make a contribution to safety assessment for geological disposal of high level radioactive and/or TRU waste, we need to assess long-term stability of geological environment and predict long-term changes of geotectonic events that will occur in the future, especially for Quaternary period ( 2.6 million years ago-present). In the most case, we investigate chronological data of geological events by radiometric dating. When some geological samples have no objects to which radiometric dating method can be applied (e.g., zircon, biotite, wood fragments and plant residues), we can use tephrochronology, which is geological dating method using each layer of tephra (erupted volcanic ash), for dating of geological layers. This chronological method is essential in Japan, where volcanism is very active. Tephra is usually characterized by petrographic characteristics and/or chemical composition (mainly major elements) of volcanic glasses and/or minerals in tephra. In Tono Geoscience Center (Japan Atomic Energy Agency), we develop an analytical technique of chemical composition including trace elements of volcanic glasses for detailed tephra identification. In this paper, we report a sample preparation procedure and analytical methods of chemical compositions of individual volcanic glass shards by using an electron probe microanalyzer and a laser ablation-inductively coupled plasma-mass spectrometer.

Determination of Pd in Pd purified by selective precipitation from spent nuclear fuel by laser ablation ICP-MS

Asai, Shiho; Ohata, Masaki*; Yomogida, Takumi; Saeki, Morihisa*; Oba, Hironori*; Hanzawa, Yukiko; Horita, Takuma; Kitatsuji, Yoshihiro

Analytical and Bioanalytical Chemistry, 411(5), p.973 - 983, 2019/02

https://doi.org/10.1007/s00216-018-1527-3

Determination of radiopalladium Pd is required for ensuring the radiation safety of Pd extracted from spent nuclear fuel for recycling or disposal. We employed laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to simplify an analytical procedure of Pd. Pd was separated through selective Pd precipitation reaction from spent nuclear fuel. Laser ablation allows direct measurement of the Pd precipitates, skipping the dissolution and dilution procedure. In this study, Pd in natural Pd standard solution was used as an internal standard, taking advantage of its absence in spent nuclear fuel. The Pd precipitate was uniformly embedded on the surface of the centrifugal filter, forming a microscopically thin flat surface of Pd. The resulting homogeneous Pd layer is suitable for obtaining a stable signal ratio of Pd/Pd. The amount of Pd obtained by LA-ICP-MS corresponds to the values obtained by conventional solution nebulization measurement.

LA-ICP-MS of rare earth elements concentrated in cation-exchange resin particles for origin attribution of uranium ore concentrate

Asai, Shiho; Limbeck, A.*

Talanta, 135, p.41 - 49, 2015/04

https://doi.org/10.1016/j.talanta.2014.12.009

A new analytical method for chondrite-normalized Rare earth elements (REE) plot has been developed in this study. Cation-exchange resin particles were used as a substrate to retain REE for laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). In LA analysis, formation of oxide and hydroxide of the light REE and Ba which causes spectral interferences in the heavy REE measurement was effectively attenuated, compared to conventional solution nebulization ICP-MS. To evaluate the applicability of the proposed method, the REE-adsorbed particles prepared by immersing them in a U-bearing solution were measured with LA-ICP-MS. Additionally, each concentration of REE in the U standard solution was determined with solution nebulization ICP-MS. The chondrite-normalized plot obtained through LA-ICP-MS analysis exhibited close agreement with that obtained through the solution nebulization ICP-MS of the REE-separated solution within the uncertainties.

REE pattern profiling with LA-ICP-MS using REE-adsorbed resin particles for nuclear forensics

Asai, Shiho; Limbeck, A.*

no journal, , 

Synthesis of calcite reference materials for in situ U-Pb dating through crystallization from amorphous calcium carbonates

Miyajima, Yusuke*; Saito, Ayaka*; Kagi, Hiroyuki*; Yokoyama, Tatsunori; Hirata, Takafumi*

no journal, , 

Calcium carbonates are ubiquitously present throughout the Earth history as animal shells, speleothems, fault-related vein fillings, and hydrothermal or cold-seep precipitates. Direct dating of carbonates provides valuable information on paleoenvironmental change, tectonics, and fluid and material cycling. U-Pb dating using high spatial-resolution LA-ICP-MS is a key technique to date natural carbonates. In situ U-Pb dating by LA-ICP-MS needs matrix-matched reference materials to correct matrix-dependent elemental fractionation in LA-ICP-MS. Roberts et al. (2017) demonstrated that a natural calcite cement WC-1 is suitable as a calcite reference material. However, the WC-1 calcite has an inhomogeneous distribution of U and Pb and lacks concordance in the U-Pb system. In this study, we synthesized novel calcite reference materials with homogeneous U and Pb concentrations and isotope ratios. We incorporated U and Pb into calcite through heat-induced crystallization from U, Pb-doped amorphous calcium carbonate (ACC). The homogeneity of the U/Ca and Pb/Ca ratios in the synthetic calcite was generally better than 8% and 13%, respectively, in relative standard deviation. The Pb/Pb ratio of the synthetic calcite was homogeneous within ~1% errors, whereas the U/Pb ratio was less homogeneous (3%-11% errors). To test the usability of the synthetic calcite, we dated WC-1 using the synthetic calcite for correction of elemental fractionation. We calculated the nominal U/Pb ratio in the synthetic calcite from its U and Pb concentrations. We then obtained the fractionation factor to correct bias between the isotope ratios and the nominal value. We could accurately date WC-1 with an ~3% precision. If the isotopic compositions of the synthetic calcite are certified by isotope-dilution technique, we could date natural carbonates with 10% precisions using the synthetic reference calcite.

Direct measurement of Cs in Cs adsorbent used for water decontamination by laser-ablation ICP-MS

Asai, Shiho*; Ohata, Masaki*; Hanzawa, Yukiko; Horita, Takuma; Yomogida, Takumi; Kitatsuji, Yoshihiro

no journal, , 

A large amount of spent Cs adsorbents used for decontaminating water in Fukushima Daiichi Nuclear Power Station are stored in the site. To dispose them safely, the estimation of Cs activity along with that of Cs is indispensable. Cs is generally measured by ICP-MS, which required the sample to be prepared in liquid form and thus the elution of Cs from the Cs adsorbents is essential. However, this approach suffers from the high radiation dose from Cs. In this study, we quantified Cs in a Cs adsorbent using the Cs/Cs ratio obtained by LA-ICP-MS and Cs radioactivity obtained by gamma spectrometry. To evaluate the applicability, we employed a Cs -containing water sample to prepare a model spent Cs adsorbent with a certified Cs activity. The resulting Cs activity of 0.36 Bq calculated by Cs /Cs ratio of 0.41 0.02 and Cs activity agreed well with that of the originally determined Cs activity in the model spent Cs adsorbent, demonstrating that the proposed technique has high validity to Cs determination of a real sample.

Simultaneous determination of zircon U-Pb age and titanium concentration using LA-ICP-MS; A Case study of the Okueyama granite, Kyusyu, Japan

Ito, Daichi*; Ishibashi, Kozue*; Sakata, Shuhei*; Yokoyama, Tatsunori; Ogita, Yasuhiro; Yagi, Koshi*; Ono, Takeshi*; Yuguchi, Takashi*

no journal, , 

no abstracts in English

A New quantification method for trace elements using laser ablation-inductively coupled plasma-mass spectrometry

Yanagisawa, Kayo; Matsueda, Makoto; Furukawa, Makoto*; Ishiniwa, Hiroko*; Wada, Toshihiro*; Hirata, Takafumi*; Takagai, Yoshitaka*

no journal, , 

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is more sensitive than other imaging analysis methods. The method requires matrix-compatible certified reference materials (CRMs) for the quantification of target elements. However, CRMs suitable for biological samples are rarely commercially available, making quantification difficult with conventional LA-ICP-MS methods. This study used a dual gas flow system combined with an isotope dilution method. In this system, two aerosols, an ablation sample and a nebulised spike solution, are mixed via a proprietary dual-port chamber. The developed method was used to quantify Fe and Sr in the CRMs and agreed with the certified values. In addition, biological samples (teeth and otoliths) were analysed and compared with values obtained by conventional chemical analysis to demonstrate their potential application for quantitative mapping.