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Journal Articles

Analytical method for the determination of $$^{211}$$At using an $$alpha$$-scintillation-camera system and thin-layer chromatography

Segawa, Mariko; Nishinaka, Ichiro*; Toh, Yosuke; Maeda, Makoto

Journal of Radioanalytical and Nuclear Chemistry, 326(1), p.773 - 778, 2020/10

 Times Cited Count:0 Percentile:100(Chemistry, Analytical)

Journal Articles

Measurement of cesium isotopic ratio by thermal ionization mass spectrometry for neutron capture reaction studies on $$^{135}$$Cs

Shibahara, Yuji*; Nakamura, Shoji; Uehara, Akihiro*; Fujii, Toshiyuki*; Fukutani, Satoshi*; Kimura, Atsushi; Iwamoto, Osamu

Journal of Radioanalytical and Nuclear Chemistry, 325(1), p.155 - 165, 2020/07

 Times Cited Count:0 Percentile:100(Chemistry, Analytical)

The measurements of isotopic ratios of Cs samples by thermal ionization mass spectrometry were performed for the analysis of their samples used to evaluate nuclear data obtained for $$^{135}$$Cs. To obtain a high intensity and stable ion beam, the effects of additive agents on the ionization of Cs were examined. The effect of silicotungstic acid on the ionization of Cs was the largest among the additive agents studied in the present study, while the silicotungstic acid also showed the largest isobaric interference of polyatomic ions. It was demonstrated that as small as 2$$times$$10$$^{-13}$$ g of a Cs sample was sufficient to achieve the analytical precision required to measure the $$^{135}$$Cs/$$^{137}$$Cs ratio in the case where an additive agent of TaO/glucose was employed. After examining of the analytical conditions, such as the interference effect due to Ba, the measurements of the isotopic ratios of two Cs samples used in our study using TIMS were conducted, and it was discussed how much the ratios contributed to evaluation of the neutron capture cross-section of $$^{135}$$Cs.

Journal Articles

Sorption behavior of selenide on montmorillonite

Sugiura, Yuki; Tomura, Tsutomu*; Ishidera, Takamitsu; Doi, Reisuke; Francisco, P. C. M.; Shiwaku, Hideaki; Kobayashi, Toru; Matsumura, Daiju; Takahashi, Yoshio*; Tachi, Yukio

Journal of Radioanalytical and Nuclear Chemistry, 324(2), p.615 - 622, 2020/05

 Times Cited Count:0 Percentile:100(Chemistry, Analytical)

Journal Articles

Cesium concentrations in various environmental media at Namie, Fukushima

Heged$"u$s, M.*; Shiroma, Yoshitaka*; Iwaoka, Kazuki*; Hosoda, Masahiro*; Suzuki, Takahito*; Tamakuma, Yuki*; Yamada, Ryohei; Tsujiguchi, Takakiyo*; Yamaguchi, Masaru*; Ogura, Koya*; et al.

Journal of Radioanalytical and Nuclear Chemistry, 323(1), p.197 - 204, 2020/01

 Times Cited Count:1 Percentile:100(Chemistry, Analytical)

The radioactivity of cesium in the water and sediments of two major rivers was measured along with airborne radioactivity in Namie Town, after the recent partial lift on the evacuation order in 2017. The observed concentrations were up to 384 $$pm$$ 11 mBq/L for $$^{137}$$Cs in unfiltered water and 1.28 $$pm$$ 0.09 mBq/m$$^{3}$$ for $$^{137}$$Cs in air, while the sediment had a maximum of 44900 $$pm$$ 23.4 Bq/kg for $$^{137}$$Cs. The $$^{134}$$Cs/$$^{137}$$Cs ratios indicate the main origin of the cesium in the sediment to be Unit 1 in good agreement with previous reports on the accident.

Journal Articles

Improvement in flow-sheet of extraction chromatography for trivalent minor actinides recovery

Watanabe, So; Senzaki, Tatsuya; Shibata, Atsuhiro; Nomura, Kazunori; Takeuchi, Masayuki; Nakatani, Kiyoharu*; Matsuura, Haruaki*; Horiuchi, Yusuke*; Arai, Tsuyoshi*

Journal of Radioanalytical and Nuclear Chemistry, 322(3), p.1273 - 1277, 2019/12

 Times Cited Count:0 Percentile:100(Chemistry, Analytical)

Journal Articles

Repeatability and reproducibility of measurements of low dissolved radiocesium concentrations in freshwater using different pre-concentration methods

Kurihara, Momo*; Yasutaka, Tetsuo*; Aono, Tatsuo*; Ashikawa, Nobuo*; Ebina, Hiroyuki*; Iijima, Takeshi*; Ishimaru, Kei*; Kanai, Ramon*; Karube, Jinichi*; Konnai, Yae*; et al.

Journal of Radioanalytical and Nuclear Chemistry, 322(2), p.477 - 485, 2019/11

 Times Cited Count:0 Percentile:100(Chemistry, Analytical)

We assessed the repeatability and reproducibility of methods for determining low dissolved radiocesium concentrations in freshwater in Fukushima. Twenty-one laboratories pre-concentrated three of 10 L samples by five different pre-concentration methods (prussian-blue-impregnated filter cartridges, coprecipitation with ammonium phosphomolybdate, evaporation, solid-phase extraction disks, and ion-exchange resin columns), and activity of radiocesium was measured. The z-scores for all of the $$^{137}$$Cs results were within $$pm$$2, indicating that the methods were accurate. The relative standard deviations (RSDs) indicating the variability in the results from different laboratories were larger than the RSDs indicating the variability in the results from each separate laboratory.

Journal Articles

Studies on processes for recovering uranium from sediment wastes

Ohashi, Yusuke; Ikeda, Yasuhisa*

Journal of Radioanalytical and Nuclear Chemistry, 321(2), p.683 - 691, 2019/08

 Times Cited Count:0 Percentile:100(Chemistry, Analytical)

Sediment waste generated from the waste solution of uranium handling facilities contains uranium and iron. In this study, we examined methods to selectively separate uranium from the waste without using nitric acid. Uranium dissolved in 0.5 $$ sim$$ 2.5M sulfuric acid, 1M hydrochloric acid, and 5M perchloric acid was selectively precipitated by adding oxalic acid. In addition, when oxalic acid and NCP are added together in 2.5M sulfuric acid, it seems that new insoluble uranium compounds are formed. Consequently, precipitation ratios of uranium was improved. Uranium was selectively precipitated from the sulfuric acid solution containing Fe and Al, and the precipitation ratio of uranium became 99%.

Journal Articles

Optimization of an isothermal gas-chromatographic setup for the chemical exploration of dubnium (Db, Z = 105) oxychlorides

Chiera, N. M.; Sato, Tetsuya; Tomitsuka, Tomohiro; Asai, Masato; Ito, Yuta; Shirai, Kaori*; Suzuki, Hayato; Tokoi, Katsuyuki; Toyoshima, Atsushi; Tsukada, Kazuaki; et al.

Journal of Radioanalytical and Nuclear Chemistry, 320(3), p.633 - 642, 2019/06

 Times Cited Count:0 Percentile:100(Chemistry, Analytical)

An isothermal gas-chromatographic (IGC) device has been developed and tested for on-line gas phase studies of volatile oxychlorides of short-lived group-5 transition metals. Radioisotopes of niobium and tantalum, produced in nuclear fusion evaporation reactions, are directly flushed into the IGC setup by an inert gas-jet. Oxychloride compounds are formed by the addition of SOCl$$_2$$ and O$$_2$$. Parameters influencing the formation and transport of NbOCl$$_3$$ and TaOCl$$_3$$ are investigated. For nuclides with half-lives ($$t_{1/2}$$) of about 30 s, an overall efficiency of 7% is obtained, rendering the IGC setup suitable for the chemical exploration of $$^{262}$$Db($$t_{1/2}$$ = 34s).

Journal Articles

Low $$^{137}$$Cs retention capability of organic layers in Japanese forest ecosystems affected by the Fukushima nuclear accident

Koarashi, Jun; Atarashi-Andoh, Mariko

Journal of Radioanalytical and Nuclear Chemistry, 320(1), p.179 - 191, 2019/04

 Times Cited Count:5 Percentile:8.35(Chemistry, Analytical)

To quantify the $$^{137}$$Cs retention behavior in forest-floor organic layers in relation to the litter dynamics, litter samples were collected at five forest sites in Fukushima in 2011 and 2015, and separated into eight fractions with different precursor species and degrees of degradation; afterward, $$^{137}$$Cs inventory was determined in each litter fraction. The ecological half-lives of $$^{137}$$Cs in the litter fractions were estimated to be from 0.7 to 4.4 years and found to depend not on the sampling site but rather on the precursor species of the litter materials. Broadleaf- and pine-needle-originated litter fractions exhibited shorter ecological half-lives of $$^{137}$$Cs, while those of cedar-originated and finely fragmented litter fractions were longer. The results suggested that the organic layers in Japanese forest ecosystems have a low $$^{137}$$Cs retention capability, although it differs depending on the forest type.

Journal Articles

Secondary radiocesium contamination of agricultural products by resuspended matter

Nihei, Naoto*; Yoshimura, Kazuya; Okumura, Taiga*; Tanoi, Keitaro*; Iijima, Kazuki; Kogure, Toshihiro*; Nakanishi, Tomoko*

Journal of Radioanalytical and Nuclear Chemistry, 318(1), p.341 - 346, 2018/10

 Times Cited Count:1 Percentile:75.54(Chemistry, Analytical)

Journal Articles

Correlation between Am(III)/Eu(III) selectivity and covalency in metal-chalcogen bonds using density functional calculations

Kaneko, Masashi; Watanabe, Masayuki

Journal of Radioanalytical and Nuclear Chemistry, 316(3), p.1129 - 1137, 2018/06

 Times Cited Count:5 Percentile:21.94(Chemistry, Analytical)

We applied density functional theory calculations to Am(III) and Eu(III) complexes with chalcogen-donor ligands of the formula N(EPMe$$_{2}$$)$$_{2}$$$$^{-}$$ (E = O, S, Se, Te). We calculated the equilibrium structures and relative stabilities of the complexes in the complexation reaction. The results indicated that the tendency of the relative stability is O $$ll$$ S $$sim$$ Se $$sim$$ Te, which is consistent with the trend of soft acid classification. Molecular orbital overlap population analysis suggested that this tendency can be correlated with the bonding type in the covalent interaction between the f-orbitals of the metal atom and the chalcogen-donor atoms.

Journal Articles

Am, Cm recovery from genuine HLLW by extraction chromatography

Watanabe, So; Sano, Yuichi; Kofuji, Hirohide; Takeuchi, Masayuki; Shibata, Atsuhiro; Nomura, Kazunori

Journal of Radioanalytical and Nuclear Chemistry, 316(3), p.1113 - 1117, 2018/06

 Times Cited Count:3 Percentile:40.19(Chemistry, Analytical)

Journal Articles

Radiation-induced degradation of aqueous 2-chlorophenol assisted by zeolites

Kumagai, Yuta; Kimura, Atsushi*; Taguchi, Mitsumasa*; Watanabe, Masayuki

Journal of Radioanalytical and Nuclear Chemistry, 316(1), p.341 - 348, 2018/04

 Times Cited Count:0 Percentile:100(Chemistry, Analytical)

We studied effect of adsorption and condensation by zeolites on radiation-induced degradation of aqueous 2-chlorophenol (2-ClPh). This study aims to demonstrate that the solid-phase extraction using zeolites has potential advantage in treatments of aqueous organic pollutants. Among three zeolites examined in this study, a mordenite type zeolite (HMOR) that has a high Si to Al ratio (127 $$pm$$ 3) exhibited preferable performance as the matrix for the 2-ClPh degradation. HMOR adsorbed far more 2-ClPh than the other zeolites, which have lower Si/Al ratios. The irradiation of HMOR induced degradation of adsorbed 2-ClPh into Cl$$^{-}$$ and organic by-products. We found a significant increase in Cl$$^{-}$$ production by HMOR. The yield of Cl$$^{-}$$ production in the presence of HMOR was as high as the yield in aqueous solution of 2-ClPh at a concentration 10 times higher. The increased Cl$$^{-}$$ production indicates that the high concentration of adsorbed 2-ClPh led to effective use of the adsorbed energy of HMOR.

Journal Articles

Overall approaches and experiences of first-time participants in the Nuclear Forensics International Technical Working Group's Fourth Collaborative Material Exercise (CMX-4)

Ho, D. M. L.*; Nelwamondo, A. N.*; Okubo, Ayako; Rameb$"a$ck, H.*; Song, K.*; Han, S.-H.*; Hancke, J. J.*; Holmgren, S.*; Jonsson. S.*; Kataoka, Osamu; et al.

Journal of Radioanalytical and Nuclear Chemistry, 315(2), p.353 - 363, 2018/02

 Times Cited Count:0 Percentile:100(Chemistry, Analytical)

The Fourth Collaborative Material Exercise (CMX-4) of the Nuclear Forensics International Technical Working Group (ITWG) registered the largest participation for this exercise in nuclear forensics, with seven of the 17 laboratories participating for the first time. In this paper, participants from five of the first-time laboratories shared their individual experience in this exercise, from preparation to analysis of samples. The exercise proved to be highly useful for testing procedures, repurposing established methods, exercising skills, and improving the understanding of nuclear forensic signatures and their interpretation trough the post-exercise review meeting.

Journal Articles

The Application of radiochronometry during the 4th collaborative materials exercise of the nuclear forensics international technical working group (ITWG)

Kristo, M. J.*; Williams, R.*; Gaffney, A. M.*; Kayzar-Boggs, T. M.*; Schorzman, K. C.*; Lagerkvist, P.*; Vesterlund, A.*; Rameb$"a$ck, H.*; Nelwamondo, A. N.*; Kotze, D.*; et al.

Journal of Radioanalytical and Nuclear Chemistry, 315(2), p.425 - 434, 2018/02

 Times Cited Count:4 Percentile:29.78(Chemistry, Analytical)

In a recent international exercise, 10 international nuclear forensics laboratories successfully performed radiochronometry on three low enriched uranium oxide samples, providing 12 analytical results using three different parent-daughter pairs serving as independent chronometers. The vast majority of the results were consistent with one another and consistent with the known processing history of the materials. In general, for these particular samples, mass spectrometry gave more accurate and more precise analytical results than decay counting measurements. In addition, the concordance of the $$^{235}$$U-$$^{231}$$Pa and $$^{234}$$U-$$^{230}$$Th chronometers confirmed the validity of the age dating assumptions, increasing confidence in the resulting conclusions.

Journal Articles

Production of iodine radionuclides using $$^{7}$$Li ion beams

Nishinaka, Ichiro*; Yokoyama, Akihiko*; Washiyama, Koshin*; Makii, Hiroyuki; Hashimoto, Kazuyuki*

Journal of Radioanalytical and Nuclear Chemistry, 314(3), p.1947 - 1965, 2017/12

 Times Cited Count:2 Percentile:64.19(Chemistry, Analytical)

Production cross sections of iodine, tellurium and antimony radionuclides in the 24-59 MeV $$^{7}$$Li + $$^{nat}$$Sn reaction have been measured by the conventional stacked foil technique with $$gamma$$-ray spectrometry. Excitation functions of the production cross sections were compared with a statistical model calculation. The contributions of complete and incomplete fusion in the production of observed radionuclides are discussed from the view points of production routes in the nuclide chart and decays for iodine, tellurium and antimony nuclides. The integral yields of $$^{123,124,125,126}$$I were deduced from the calculated excitation functions in the $$^{7}$$Li induced reactions on Sn isotopes in view of the production of medically important $$^{123,124}$$I. The results are discussed by comparing with literature values in the other reactions.

Journal Articles

Development of determination method of $$^{93}$$Mo content in metal waste generated at the Japan Power Demonstration Reactor

Shimada, Asako; Omori, Hiroyuki*; Kameo, Yutaka

Journal of Radioanalytical and Nuclear Chemistry, 314(2), p.1361 - 1365, 2017/11

 Times Cited Count:0 Percentile:100(Chemistry, Analytical)

A separation method of Mo from Nb, Zr, and the matrix elements of rubble waste was modified to determine the content of $$^{93}$$Mo in metal waste. A separation scheme to treat 1 g of metal waste was established by optimizing the amount of ascorbic acid, the rinsing solution, and repeating of the procedure. A thin-layer source was prepared using direct drop deposition and evaporation to measure $$^{93}$$Mo content. Finally, $$^{93}$$Mo content in the metal waste generated at the Japan Power Demonstration Reactor was analyzed using the developed method.

Journal Articles

Sources of $$^{137}$$Cs fluvial export from a forest catchment evaluated by stable carbon and nitrogen isotopic characterization of organic matter

Muto, Kotomi; Atarashi-Andoh, Mariko; Koarashi, Jun; Takeuchi, Erina; Nishimura, Shusaku; Tsuzuki, Katsunori; Matsunaga, Takeshi*

Journal of Radioanalytical and Nuclear Chemistry, 314(1), p.403 - 411, 2017/10

 Times Cited Count:9 Percentile:13.35(Chemistry, Analytical)

Fluvial export of particulate and dissolved $$^{137}$$Cs was investigated to reveal its sources and transfer mechanisms in a broadleaved forest catchment using a continuous collection system. The finest size fraction ($$<$$ 75$$mu$$m), consisting of decomposed litter and surface mineral soil, was the dominant fraction in the particulate $$^{137}$$Cs load, although the contribution of coarser size fractions increased during high water discharge in 2014. The dissolved $$^{137}$$Cs originated from the decomposition of $$^{137}$$Cs-contaminated litter. Temporal changes in $$^{137}$$Cs distribution in the litter-mineral soil system indicated that the dissolved $$^{137}$$Cs load will be moderated in several years, while particulate $$^{137}$$Cs load has the potential to continue for a long time.

Journal Articles

Uranium age-dating using in-situ isotope ratios by thermal ionization mass spectrometry for nuclear forensics

Okubo, Ayako; Shinohara, Nobuo; Magara, Masaaki

Journal of Radioanalytical and Nuclear Chemistry, 314(1), p.231 - 234, 2017/10

 Times Cited Count:0 Percentile:100(Chemistry, Analytical)

The model date of two enriched uranium materials were determined using a new method for nuclear forensics investigation. In this method, the $$^{230}$$Th/$$^{234}$$U ratio was calculated without spike addition from measured ratios of $$^{230}$$Th/$$^{234}$$Th and $$^{234}$$U/$$^{238}$$U, and calculated $$^{234}$$Th/$$^{238}$$U ratio in secular equilibrium. The obtained model date for the low-enriched uranium material was agreed with the known production date within uncertainty. For the highly enriched uranium material, slightly younger model date than the known production date was obtained. The $$^{234}$$U interference on $$^{234}$$Th counting in thermal ionization mass spectrometry measurement was suspected as a potential cause.

Journal Articles

Separation of Zr in the rubble waste generated at the Fukushima Daiichi Nuclear Power Station

Shimada, Asako; Kameo, Yutaka

Journal of Radioanalytical and Nuclear Chemistry, 311(3), p.1613 - 1618, 2017/03


 Times Cited Count:0 Percentile:100(Chemistry, Analytical)

Separation method of Zr using trans uranium resin (TRU resin) was developed. Approximately 100% of Zr, Nb, Bi, Th, and U and a part of Mo and Hg were extracted on the TRU resin from 3 M HNO $$_{3}$$ solution and separated from Li, Be, Mg, Al, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr,Ag, Cd, In, Cs, Ba. Approximately 100% of Zr, Nb, and U were striped from the TRU resin with 0.01 M HF and 10% of Mo, 7.1% of Hg, 77% of Bi, and 20% of Th were also included in the stripping solution. In order to measure $$^{93}$$Zr with inductively coupled plasma mass spectrometry (ICP-MS), Zr has to be separated from Nb and Mo to avoid isobaric interference. Therefore, further purification of Zr using tetra valent actinide resin (TEVA resin) was applied. The developed method was evaluated with the simulated rubble sample solution. Although a part of Zr was eluted during sample loading, most of Zr was extracted on the TRU resin and separated major elements of the rubble sample. Finally, Zr was separated from Nb and Mo with the TEVA resin.

233 (Records 1-20 displayed on this page)