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Emori, Tatsuya; Kitatsuji, Yoshihiro; Ban, Yasutoshi
JAEA-Technology 2024-025, 20 Pages, 2025/03
JAEA-Technology-2024-025.pdf:1.65MB
Radioisotope Thermoelectric Generators (RTGs) using the decay heat of Pu-238 has been applied for outer planet missions far from Jupiter, where solar power is limited. However, no facilities are available to produce Pu-238 for space probes in Japan. Moreover, the use of nuclear materials for the space exploration is difficult in term of the regulation. Thus, we focused on Am-241 whose half-life is around 432 years as an alternative heat source for RTGs. This report describes the procedure of separating Am-241 decayed from Pu-241 in aged plutonium oxide. Two experiments were performed: one using solid-liquid extraction and the other combining liquid-liquid extraction and solid-liquid extraction. Packed columns were used in the experiments, with their number reduced by less than one-fifth in the latter experiment compared to the former. Furthermore, the time required for separation in the latter experiment was less than half that of the former. We performed the separation experiments six times, collecting a total of approximately 0.43 g of Am-241 as an oxalate salt.
Cs/
Cs isotope ratioShimada, Asako; Tsukahara, Takehiko*; Nomura, Masao*; Takeda, Seiji
Journal of Radioanalytical and Nuclear Chemistry, 333(12), p.6297 - 6310, 2024/12
Times Cited Count：0 Percentile：0.00(Chemistry, Analytical)Ieda, Junichi; Fukada, Yukimasa; Fukuda, Tatsuo
Nihon Genshiryoku Gakkai-Shi ATOMO
, 66(10), p.521 - 524, 2024/10
no abstracts in English
Matsueda, Makoto
Hosha Kagaku, (50), p.55 - 57, 2024/09
Concentrations and isotope ratios of 
Tc, 
I, and Pu isotopes, which are long-lived nuclides, provide us the important information in many fields such as the decommissioning of nuclear facilities and investigation of environmental dynamics. It will increase the effort for their analysis in the future. Therefore, their analytical methods should be developed for corresponding many samples, and inductively coupled plasma mass spectrometry (ICP-MS) is expected to be a technique to help resolve them. However, there are some problems in the analysis of these nuclides, and technological innovations have not progressed yet. In this paper, we attempted to solve these problems by combining multiple separation systems with ICP-MS.
Matsueda, Makoto; Takagai, Yoshitaka*
Bunseki (Internet), 2024(6), p.195 - 200, 2024/06
The analytical demand for radioisotopes (RI) contained in radioactive waste from the decommissioning of nuclear power plants, research activities and nuclear accidents is increasing. However, traditional analytical methods of RI are mostly complicated and time-consuming, it is necessary to be rapid, simple and automatic methods. This paper describes the rapid analytical techniques of inductively coupled plasma-mass spectrometry in recent years, which current technology, challenges and perspective for the future.
Yamamoto, Yusuke*; Watanabe, Takahiro; Niwa, Masakazu; Shimada, Koji
JAEA-Testing 2023-003, 67 Pages, 2024/02
JAEA-Testing-2023-003.pdf:4.63MB
A long-term geosphere stability for geological disposal is evaluated by the past geological environmental changes and modern conditions. Stable hydrogen and oxygen isotope ratios (
D, 
O) of geological samples are useful information to estimate the past environmental changes and modern conditions. Recently, the thermal conversion elemental analyzer and isotope ratio mass spectrometer (TC-EA/IRMS) were installed in the Tono Geoscience Center for D and O measurements of geological samples. In this study, we reported analytical methods of D and O using international standard reference materials. In addition, evaluation tests of uncertainty by repeated analyses of the standards were performed using the TC-EA/IRMS. Furthermore, the D and O analyses by the TC- EA/IRMS were also applied to fault rock samples.
investigated using synchrotron X-ray photoelectron spectroscopySekiguchi, Tetsuhiro; Yokoyama, Keiichi; Yaita, Tsuyoshi
Photon Factory Activity Report 2023 (Internet), 5 Pages, 2024/00
For nuclear transmutation of cesium-135 (Cs), which is long-lived fission product, we are developing selective absorbent which takes only Cs atom in, but does not CsI. In this study, absorbing property of Cs atom or CsI into fullerene (C) solid has been investigated using synchrotron-based angle-dependent X-ray photoelectron spectroscopy (ARXPS). It was found that Cs penetrates into C deep bulk. In contrast, CsI does not diffuse into bulk, although CsI over-layer was formed on the shallow surface. Furthermore, XPS spectra were measured as a function of Ar
-sputtering time in order to know Cs concentration profiles in further deep region. Results showed that Cs penetrates into deep region of several hundreds 
.
Yanagisawa, Kayo; Matsueda, Makoto; Furukawa, Makoto*; Ishiniwa, Hiroko*; Wada, Toshihiro*; Hirata, Takafumi*; Takagai, Yoshitaka*
Analyst, 148(18), p.4291 - 4299, 2023/09
Times Cited Count：2 Percentile：25.29(Chemistry, Analytical)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.
Tomita, Ryohei; Tomita, Jumpei; Suzuki, Daisuke; Yasuda, Kenichiro; Miyamoto, Yutaka
Hosha Kagaku, (48), p.1 - 15, 2023/09
Secondary Ion Mass Spectrometry (SIMS) is the method to detect secondary ions produced by the sputtering of primary ions. SIMS is one of effective method to measure isotopic composition of particles containing nuclear material in environmental sample for safeguards. We are a group member of the International Atomic Energy Agency (IAEA)'s network of analytical laboratories and have developed analytical techniques using SIMS and other mass spectrometers for nuclear safeguards. We will introduce the principle of SIMS and analytical techniques developed by our group to measure isotopic composition of uranium particles which having a particle diameter of micron order in environmental sample for safeguards.
Yasuda, Satoshi; Di
o, W. A.*; Fukutani, Katsuyuki
Vacuum and Surface Science, 66(9), p.514 - 519, 2023/09
Monolayer graphene, representative of atomically thin crystals, has recently shown unexpectedly high proton and deuteron permeability under ambient conditions. It also permeates (filters) hydrogen (deuterium) isotope ion with high selectivity. These results suggest possible ways of developing novel and efficient hydrogen isotope gas enrichment techniques for manufacturing silicon semiconductors, optical fibers, drug development, nuclear fusion, and other related applications. And yet, despite its importance, experimental studies remain scarce and the separation mechanism contentious. Here, we introduce our recent findings on how quantum tunneling of hydrons through graphene could account for the high hydron selectivity of graphene.
Watanabe, Teppei*; Sekine, Yurina; Ikeda-Fukazawa, Tomoko*
Macromolecules, 56(16), p.6217 - 6221, 2023/08
Times Cited Count：4 Percentile：40.28(Polymer Science)To investigate the ability of hydrogels to separate hydrogen isotopes in water, we analyzed the Raman spectra of poly-N,N-dimethylacrylamide (PDMAA) hydrogels containing deuterated water during dehydration. The results show a significant fractionation of hydrogen isotopes during dehydration. The D molar ratio of the hydrogel increases from 0.056 to 
0.2 during dehydration from 90.5 wt% to 5 wt% in water content. Deuterated water preferentially forms hydrogen bonds with hydrophilic groups of the polymer in hydrogels because of the difference in strengths of hydrogen bonds between protium and deuterium. As a result, normal water preferentially evaporates in the initial stage of dehydration, leaving deuterated water in the drying hydrogel. The results suggest that hydrogels are an efficient material for isotope fractionation with evaporation.
Miyamoto, Yutaka; Suzuki, Daisuke; Tomita, Ryohei; Tomita, Jumpei; Yasuda, Kenichiro
Isotope News, (786), p.22 - 25, 2023/04
no abstracts in English
Nagai, Takayuki; Tone, Masaya; Katsuoka, Nanako; Okamoto, Yoshihiro; Baba, Yuji*; Akiyama, Daisuke*
Photon Factory Activity Report 2022 (Internet), 3 Pages, 2023/00
no abstracts in English
Tomita, Jumpei; Tomita, Ryohei; Suzuki, Daisuke; Yasuda, Kenichiro; Miyamoto, Yutaka
KEK Proceedings 2022-2, p.154 - 158, 2022/11
Precise determination of minor U isotopes (
U and 
U) of particles from the safeguard environmental samples is powerful method for detecting the undeclared nuclear activities. In this study, preparation method of U particle was examined to utilize for the minor U isotope determination. The porous silica particles were used as the particle matrix and lutetium was mixed to the impregnation solution as U impregnation indicator for the particle picking. The result of the Scanning Electron Microscope indicated that the contacting the solution with Si particles overnight gently could produce the impregnated particles effectively rather than the mixing them with PFA stick.
Nagai, Takayuki; Okamoto, Yoshihiro; Baba, Yuji*; Akiyama, Daisuke*; Arima, Tatsumi*
Photon Factory Activity Report 2021 (Internet), 2 Pages, 2022/00
no abstracts in English
Cu and 
Cu via the Zn(n, p)Cu and 
Zn(n, np/d)Cu reactions using accelerator neutronsKawabata, Masako*; Motoishi, Shoji*; Ota, Akio*; Motomura, Arata*; Saeki, Hideya*; Tsukada, Kazuaki; Hashimoto, Shintaro; Iwamoto, Nobuyuki; Nagai, Yasuki*; Hashimoto, Kazuyuki*
Journal of Radioanalytical and Nuclear Chemistry, 330(3), p.913 - 922, 2021/12
Times Cited Count：8 Percentile：67.14(Chemistry, Analytical)Both Cu and Cu are promising radionuclides in nuclear medicine. Production yields of these radionuclides were quantified by irradiating 55.4 g of natural zinc with accelerator neutrons. Clinically suitable Cu and Cu yields were estimated by experimental based numerical simulations using 100 g of enriched Zn and Zn, respectively, and elevated neutron fluxes from 40 MeV, 2 mA deuterons. A combined thermal- and resin-separation method was developed to isolate Cu and Cu from zinc, resulting in 73% separation efficiency and 97% zinc recovery. Such methods can provide large scale production of Cu and Cu for clinical applications.
Cs/Cs isotopic ratio in soil collected near Fukushima Daiichi Nuclear Power Station through mass spectrometryShimada, Asako; Tsukahara, Takehiko*; Nomura, Masao*; Kim, M. S.*; Shimada, Taro; Takeda, Seiji; Yamaguchi, Tetsuji
Journal of Nuclear Science and Technology, 58(11), p.1184 - 1194, 2021/11
Times Cited Count：7 Percentile：62.34(Nuclear Science & Technology)Determining the completeness of nuclear reactor decommissioning is an important step in safely utilizing nuclear power. For example, Cs from the Fukushima Daiichi Nuclear Power Station (FDNPS) accident can be treated as background radioactivity, so determining the origin of Cs is essential. To accomplish this, measuring the Cs/Cs isotope ratio can be useful, so this study optimized a solvent extraction method, with calix[4]arene-bis(t-octylbenzo-crown-6) [BOBCalixC6] in 1-octanol, to purify radioactive Cs, radiocesium, from a solution of major environmental soil elements and mass spectrometry interference elements. This optimized method was applied to Cs purification in soil samples (40 g), and the final solutions contained a total of 10
g/ml of the major soil elements and ng/ml concentrations at most of interfering elements. Soil samples collected near the FDNPS were then purified, and the Cs/Cs isotope ratios were measured, using both thermal ionization mass spectrometry (TIMS) and triple quadrupole induced coupled plasma mass spectrometry (ICP-QQQ). The results of each of these measurements were compared, and we found that Cs isotope ratios obtained by TIMS were more precise, by an order of magnitude, while the ICP-QQQ results possessed good abundance sensitivities. A slightly higher Cs/Cs ratio in the northwest area of the FDNPS was observed, while other areas exhibited similar values, all within the measurement error range, which indicated different origins of radiocesium. These results agreed with previously reported 
Cs/Cs activity distributions, suggesting that this ratio may be useful in identifying radiocesium origins for evaluating future nuclear reactor decommissions.
Cs to web-building spiders, 
, and its pathways; A Preliminary study using stable carbon and nitrogen isotope analysesTanaka, Sota; Kakinuma, Hotaru*; Adachi, Taro*; Atarashi-Andoh, Mariko; Koarashi, Jun
Journal of Nuclear Science and Technology, 58(4), p.507 - 514, 2021/04
Times Cited Count：1 Percentile：10.00(Nuclear Science & Technology)Understanding the pathways of Cs transfer to predatory spiders is useful to assess long-term behavior of Cs in the environment, because spiders obtain food resources from both the grazing and detritus food chains in terrestrial-aquatic linking forest ecosystems. In the present study, we collected spider samples at forest interior and riverside. The sample collection was approximately 6.5 years after the FDNPP accident. Moreover, a transfer factor value (T
) for Cs in spiders was quantified. Stable carbon and nitrogen isotope ratios (
C and 
N) of the spiders were also investigated to estimate the transfer pathways of Cs to the spiders.
N isotopic enrichment plant and its cost for nitride fuel fabrication (Contract research)Takano, Masahide
JAEA-Review 2020-080, 24 Pages, 2021/03
JAEA-Review-2020-080.pdf:1.71MB
Nitride is one of the potential fuel forms for minor actinide transmutation by the accelerator driven system. However, to avoid the 
C production from N by (n, p) reaction in the fuel, the special N
gas highly enriched with N is needed for the fuel fabrication. To realize the availability of such gas has been an important issue. In this report, the degree of N enrichment and gas amount required for the fuel fabrication are shown first, and then among the existing isotopic enrichment methods, N cryogenic distillation is found to be a promising method from the viewpoint of constructing a huge scale plant because of its non-hazardous feature. Some commercial plants for O enrichment based on the similar method have already been operated in Japan. Its technology and components can be applied to the N enrichment plant. Assuming the supply of N gas from a cryogenic distillation plant, a series of enrichment simulation is performed to evaluate the plant size as functions of targeted degree of enrichment and annual production. By using the simulation results, the basic specifications for plant components and equipment are designed. As a result, a huge plant for annual production of 1000 kg N gas with 99% enrichment is found to be technically feasible. The N gas production cost is also evaluated to be approximately 1/30 of the current distribution price. This survey shows the availability of N gas required for the nitride fuel fabrication in both technical and economic aspects.
Sano, Asami; Ito, Shoichi*; Suzumura, Akimasa*; Ueno, Yuichiro*; Yagi, Hikaru*; Inoue, Toru*; Kawazoe, Takaaki*
Koatsuryoku No Kagaku To Gijutsu, 30(2), p.85 - 94, 2020/10
Minerals and rocks exhibit various isotope compositions depending on their origins and histories. In interpreting their isotopic variations, the equilibrium isotope fractionation factor is a key because it depends on the environment parameters such as temperature. Recent studies have shown that the effect of pressure on the isotope fractionation, which was considered negligible compared to temperature, is significant under the conditions of the Earth's interior. In this article we review recent advances in experimental studies to determine the isotope fractionation of iron and hydrogen at high pressure over several GPa, discussing their issues and future perspectives.
