Structural investigation of simulated waste glass surface drained in operation confirmation test of 3rd TVF glass melter

Nagai, Takayuki; Hasegawa, Takehiko*

JAEA-Research 2023-008, 41 Pages, 2023/12

JAEA-Research-2023-008.pdf:7.52MB

To reduce the risks posed by stored the high-level radioactive liquid waste (HAW), Tokai Vitrification Facility (TVF) is working to produce the HAW into vitrified bodies. With the aim of steady vitrification of HAW in TVF, the vitrification technology section has manufactured a new 3rd melter with an improved bottom structure and is working to verify the performance of this melter. In this study, solidified glass samples were taken from simulated vitrified bodies produced by flowing molten glass during the bottom drain-out test in the operation confirmation of the TVF 3rd melter. And the properties of the surface layer and fracture surface of the vitrified bodies were evaluated by using Raman spectroscopy, synchrotron radiation XAFS measurement, and laser ablation inductively coupled plasma atomic emission spectroscopy (LA ICP-AES) analysis. As a result of measuring the surface layer and fracture surface of the solidified samples produced on an actual scale, a slight difference was confirmed between the properties of the surface layer and those of the fracture surface. Since the chemical composition of these simulated vitrified bodies does not contain platinum group elements, it is expected that the glass structure of solidified glass samples is different from that of the actual vitrified body. However, this sample measuring was a valuable opportunity to evaluate samples produced by using the direct energized joule heating method. The properties of cullet used the operation confirmation of the TVF 3rd melter and the cullet of another production lot were measured and analyzed in the same manner under the measuring conditions of solidified glass samples. As a result, it was confirmed that cullet with different producing histories have different glass structures even with the same chemical composition, and that differences in glass structures remain in the glass samples after melting these cullet.

Quantitative imaging of trace elements in solid samples by online isotope dilution laser ablation-inductively coupled plasma-mass spectrometry

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

Analyst, 148(18), p.4291 - 4299, 2023/09

https://doi.org/10.1039/D3AN01028G

Quantitative imaging of trace elements was successfully performed by online isotope dilution laser ablation inductively coupled plasma mass spectrometry (online LA-ICP-IDMS). The sample aerosols produced by LA are mixed online with the mist created from an isotopically enriched spike solution via an in-house cyclonic spray chamber, which has a gas port on the top. Quantification was continuously achieved in each spot; subsequently, quantitative imaging was realized. Fe and Sr were selected as the model elements, and their spot quantifications based on online-isotope dilution. The method was applied to actual biological hard tissues, and the results were compared with electron probe microanalyzer data.

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.

Power profile analysis of criticality accidents involving fissile solution boiling with considering evaporation

Watanabe, Tomoaki; Yamane, Yuichi

Journal of Nuclear Science and Technology, 9 Pages, 2023/00

https://doi.org/10.1080/00223131.2023.2290711

The total fission energy released in a criticality accident involving fissile solution boiling tends to be high because the relatively high fission power continues during boiling. Simulating fission power change correctly during boiling seems essential to estimate the total fission energy. Fission power during boiling changes depending on fissile concentration and volume as the solution evaporates. In this study, we investigated the effect of concentration and volume change on estimated total fission energy for a long time of boiling. We introduced a model calculating the evaporation of fissile solution into the modified quasi-steady-state method to simulate power change during boiling. Three CRAC experiments and the Idaho Chemical Processing Plant (ICPP) criticality accident in 1959 were analyzed. As a result, the calculated energy considering concentration and volume change during boiling reproduced the measured energy well.

Mass-spectrometric determination of iodine-129 using O-CO mixed-gas reaction in inductively coupled plasma tandem quadrupole mass spectrometry

Matsueda, Makoto; Aoki, Jo; Koarai, Kazuma; Terashima, Motoki; Takagai, Yoshitaka*

Analytical Sciences, 38(11), p.1371 - 1376, 2022/11

https://doi.org/10.1007/s44211-022-00180-w

The I analysis using ICP-MS is challenging caused by xenon-129 (Xe) and IH generated from excess stable isotope I. In this study, mass discrimination between iodine-129 (I) and interfering substances was achieved by inductively coupled plasma-tandem quadrupole mass spectrometry (ICP-MS/MS) with a dynamic reaction cell introduced a mixture gas of O and CO. As a result, the ratio of (background noise intensity at m/z 129)/I was 3.8 10 and 10 mBq/L of I was analyzed without chemical separation in the presence of 100 mg/L stable I. Spiked tests with actual rainwater were performed, and obtained values were agreed with the spiked amounts.

Using CO Reactions to Achieve Mass-spectrometric Discrimination in Simultaneous Plutonium-isotope Speciation with Inductively Coupled Plasma-Tandem Mass Spectrometry

Matsueda, Makoto; Kawakami, Tomohiko*; Koarai, Kazuma; Terashima, Motoki; Fujiwara, Kenso; Iijima, Kazuki; Furukawa, Makoto*; Takagai, Yoshitaka*

Chemistry Letters, 51(7), p.678 - 682, 2022/07

https://doi.org/10.1246/cl.220160

New methodology for a simultaneous isotope speciation of various Pu isotopes without complicated isobaric interferences is developed by using inductively coupled plasma-mass spectrometry (ICP-MS). In analyzing ICP tandem MS (ICP-MS/MS), CO gas reactions in a dynamic reaction cell (DRC) almost eliminated the background noise intensity produced by isobaric interference from isotopes originating from actinides such as Am, Cm, and U at the locations (m/z) of significant Pu isotopes (Pu, Pu, Pu, Pu, Pu).

Development of extremely small amount analysis technology for fuel debris analysis (Contract research); FY2020 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*

JAEA-Review 2021-056, 98 Pages, 2022/02

JAEA-Review-2021-056.pdf:9.08MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2020. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2019, this report summarizes the research results of the "Development of extremely small amount analysis technology for fuel debris analysis" conducted in FY2020. The fuel debris retrieved from the Fukushima Daiichi Nuclear Power Station (1F) is analyzed in the second building of the Okuma Analysis and Research Center. The characteristics of fuel debris, such as the mixture of nuclear fuel, reactor components, and concrete, are not clear, and its analysis will be the first attempt in the world. Understanding the properties of fuel debris is necessary for handling, criticality control, storage control, etc. A key technique is the chemical analysis of actinide nuclides. We develop sample pretreatment technology and separation/analysis process required for chemical analysis.

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.

Online solid-phase extraction-inductively coupled plasma-quadrupole mass spectrometry with oxygen dynamic reaction for quantification of technetium-99

Matsueda, Makoto; Yanagisawa, Kayo*; Koarai, Kazuma; Terashima, Motoki; Fujiwara, Kenso; Abe, Hironobu; Kitamura, Akihiro; Takagai, Yoshitaka*

ACS Omega (Internet), 6(29), p.19281 - 19290, 2021/07

https://doi.org/10.1021/acsomega.1c02756

Online solid-phase extraction-inductively coupled plasma-quadrupole mass spectrometry with oxygen dynamic reaction cell (online SPE-ICP-MS-DRC) was shown to be a thorough automatic analytical system, circumventing the need for human handling. At three stepwise separations (SPE-DRC-Q mass filters), we showed that interference materials allowed the coexistence of abundance ratios of 1.510 for Tc/Mo. Using this optimized system, a detection limit of Tc was 9.3 pg/L (5.9 mBq/L) for a 50 mL injection and sequential measurements were undertaken at a cycle of 24 min/sample.

Development of HCl-free solid phase extraction combined with ICP-MS/MS for rapid assessment of difficult-to-measure radionuclides, 1; Selective measurement of Zr and Mo in concrete rubble

Do, V. K.; Furuse, Takahiro; Murakami, Erina; Aita, Rena; Ota, Yuki; Sato, Soichi

Journal of Radioanalytical and Nuclear Chemistry, 327(1), p.543 - 553, 2021/01

https://doi.org/10.1007/s10967-020-07503-z

A new HCl-free chromatographic separation procedure has been developed for sequential separation of Zr and Mo from concrete matrices. Accordingly, Zr and Mo could be sensitively and selectively measured by ICP-MS/MS using ammonia reaction gas. The recoveries of greater than 90% for Zr and Mo from concretes could be achieved. The measurement condition was optimized for complete suppression of interferences from Nb and peak tailing from abundant isotopes of Zr and Mo in concrete matrices. The removal of interferences was verified by measurement of radio-contamination-free concretes used as a sample matrix blank. Method detection limits of 1.7 mBq g and 0.2 Bq g were achieved for Zr and Mo, respectively, in the concrete matrices. The interference removal factor for Nb (equivalent to the decontamination factor in radiochemical separation) was of the order of 10, and the abundance sensitivity was of the order of 10, indicating that the developed method is reliable for verifying the presence of ultralow concentrations of Zr and Mo. The present method is suitable for the rapid assessment of Zr and Mo for radioactivity inventory of concrete rubble.