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Tsuchikawa, Yusuke; Kai, Tetsuya; Abe, Yuta; Oikawa, Kenichi; Parker, J. D.*; Shinohara, Takenao; Sato, Ikken
Journal of Physics; Conference Series, 2605, p.012022_1 - 012022_6, 2023/10
We developed a method to obtain the areal density distribution of boron, which has a large neutron cross section, by means of an energy resolved neutron imaging. Commonly in a measurement of elements with very high neutron sensitivity, the quantitative measurement becomes more difficult with the amount of element due to the neutron self-shielding effect. To avoid this effect, an energy-resolved method using known cross section data was attempted, and a quantitative imaging of such elements was demonstrated at the MLF of J-PARC. This presentation introduces a measurement of melted simulated-fuel assemblies obtained in the research of the Fukushima Daiichi Nuclear Power Plant after the severe accident. Energy-dependent neutron transmission rates of the samples were measured by a neutron imaging detector, and were analyzed to obtained the areal density of boron at each position.
Nagai, Takayuki; Okamoto, Yoshihiro; Yamagishi, Hirona*; Shibata, Daisuke*; Kojima, Kazuo*; Hasegawa, Takehiko*; Sato, Seiichi*; Fukaya, Akane*; Hatakeyama, Kiyoshi*
JAEA-Research 2023-004, 45 Pages, 2023/09
The local structure of glass-forming elements and waste elements in borosilicate glasses varies with its chemical composition. In this study, simulated waste glass samples were prepared and the chemical state regarding boron (B), silicon (Si) and waste elements of iron (Fe), cesium (Cs) were estimated by using XAFS measurement in soft X-ray region. To understand the chemical stability of simulated waste glasses, XANES spectra of B K-edge, Fe L, L-edge, and Cs M, M-edge were measured on the glass surface exposed to the leachate. As a result, it was found that the glass surface exposed to the leachate was changed and it was difficult to obtain a clear XANES spectrum. From the B K-edge XANES spectra on glass surfaces exposed to the leachate, an increase in three-coordination of B-O (BO) and a decrease in four-coordination of B-O (BO) were observed compared to the glass surfaces before immersion. The XANES spectra of Fe L, L-edge, and Cs M, M-edge show that as the exposure time in the leachate increases, the Cs present on the glass surface dissolves into the leachate. The XANES spectra of Si K-edge were measured on simulated waste glass surfaces before immersion, and it was confirmed that the change in XANES spectra given by NaO concentration had a larger effect than the waste component concentration.
Yamano, Hidemasa; Takai, Toshihide; Emura, Yuki; Fukuyama, Hiroyuki*; Nishi, Tsuyoshi*; Morita, Koji*; Nakamura, Kinya*; Pellegrini, M.*
Nihon Kikai Gakkai 2023-Nendo Nenji Taikai Koen Rombunshu (Internet), 5 Pages, 2023/09
A research project has been conducting thermophysical property measurement of a eutectic melt, eutectic melting reaction and relocation experiments, eutectic reaction mechanism investigation, and physical model development on the eutectic melting reaction for reactor application analysis in order to simulate the eutectic melting reaction and relocation behavior of boron carbide as a control rod material and stainless steel during a core disruptive accident in an advanced sodium-cooled fast reactor designed in Japan. This paper describes the project overview and progress until JFY2022.
Fukai, Hirofumi*; Furuya, Masahiro*; Yamano, Hidemasa
Nuclear Engineering and Technology, 55(3), p.902 - 907, 2023/03
Times Cited Count:1 Percentile:0.01(Nuclear Science & Technology)This paper addresses reaction products and their distribution of the eutectic melting/solidifying reaction of boron carbide (BC) and stainless-steel (SS). The influence of the existence of carbon on the BC-SS eutectic reaction was investigated by comparing the iron boride (FeB)-SS reaction by Raman spectroscopy with Multivariate Curve Resolution (MCR) analysis. The scanning electron microscopy with dispersive X-ray spectrometer was also used to investigate the elemental information of the pure metals such as Cr, Ni, and Fe. In the BC-SS samples, a new layer was formed between BC/SS interface, and the layer was confirmed that the formed layer corresponded to amorphous carbon (graphite) or FeB or FeB. In contrast, a new layer was not clearly formed between FeB and SS interface in the FeB-SS samples.
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
Nagai, Takayuki; Okamoto, Yoshihiro; Yamagishi, Hirona*; Kojima, Kazuo*; Inose, Takehiko*; Sato, Seiichi*; Hatakeyama, Kiyoshi*
JAEA-Research 2022-008, 37 Pages, 2022/10
The local structure of glass-forming elements and waste elements in borosilicate glasses varies with its chemical composition. In this study, borosilicate glass frit and simulated waste glass samples were prepared and the chemical state regarding boron (B), silicon (Si) and waste elements of iron (Fe), cesium (Cs) were estimated by using XAFS measurement in soft X-ray region. Following results were obtained by XAFS measurements of simulated waste glass surfaces after immersion test to investigate the long chemical stability. (1) As the leaching time of glass samples in immersion test passed, the Cs M, M-edge XANES spectra disappeared and the Fe L, L-edge spectra changed. (2) A new compound was formed on the sample surface after the immersion test, and these changes in the surface state were confirmed by Raman spectroscopy. However, it became difficult to obtain a clear B K-edge XANES spectrum by forming a compound on glass surfaces. The Si K-edge XANES spectra of borosilicate glass frits with different NaO content were measured, and following was confirmed. (1) As the NaO concentration increases in borosilicate glass frit, the K-edge peak of Si shifts to the low energy side. (2) The intensity of the Si K-edge peak is maximum when the NaO content in glass frits was about 7wt%.
Emura, Yuki; Kamiyama, Kenji; Yamano, Hidemasa
Dai-26-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu (Internet), 4 Pages, 2022/07
no abstracts in English
Nagai, Takayuki; Okamoto, Yoshihiro; Yamagishi, Hirona*; Ota, Toshiaki*; Kojima, Kazuo*; Inose, Takehiko*; Sato, Seiichi*; Hatakeyama, Kiyoshi*
JAEA-Research 2021-010, 62 Pages, 2022/01
The local structure of glass-forming elements and waste elements in borosilicate glasses varies with its chemical composition. In this study, borosilicate glass frit and simulated waste glass samples were prepared and the local structure and chemical state regarding boron(B), oxygen(O), silicon(Si) and waste elements of iron(Fe), cesium(Cs) were estimated by using XAFS measurement in soft X-ray region. Following results were obtained by XAFS measurements of prepared glass frit and simulated waste glass samples: (1) The effect of NaO concentration on B-O coordination structure is greater than that of the waste elements concentration. (2) The height of pre-edge by O K-edge spectrum depends on the concentration of first transition elements such as Fe in glass samples. Following results were obtained by XAFS measurements of simulated waste glass samples after immersion test to investigate the long chemical stability. (1) A new compound was formed on the sample surface after the immersion test, and changes in the surface state were confirmed by Raman spectroscopy. (2) Cs on the sample surface after immersion test dissolves into the leaching solution. The Si K-edge XANES spectra of borosilicate glass frits and simulated waste glass samples included lanthanides oxide were measured, and following was confirmed. (1) As the NaO concentration increases in borosilicate glass frit, the K-edge peak of Si shifts to the low energy side. (2) The peak height of the K-edge of Si differs depending on the kind of lanthanide.
Nagai, Takayuki; Okamoto, Yoshihiro; Baba, Yuji*; Akiyama, Daisuke*; Arima, Tatsumi*
Photon Factory Activity Report 2021 (Internet), 2 Pages, 2022/00
no abstracts in English
Abe, Yuta; Tsuchikawa, Yusuke; Kai, Tetsuya; Matsumoto, Yoshihiro*; Parker, J. D.*; Shinohara, Takenao; Oishi, Yuji*; Kamiyama, Takashi*; Nagae, Yuji; Sato, Ikken
JPS Conference Proceedings (Internet), 33, p.011075_1 - 011075_6, 2021/03
Nagai, Takayuki; Okamoto, Yoshihiro; Yamagishi, Hirona*; Ota, Toshiaki*; Kojima, Kazuo*; Inose, Takehiko*; Sato, Seiichi*; Hatakeyama, Kiyoshi*
JAEA-Research 2020-009, 48 Pages, 2020/09
The local structure of glass-forming elements and waste elements in waste glass varies with its chemical composition. In this study, borosilicate glass frit and simulated waste glass samples were prepared and the local structure and chemical state regarding boron (B), oxygen (O), and waste elements of cerium (Ce), cesium (Cs) were estimated by using XAFS measurement in soft X-ray region. Following results were obtained by XAFS measurements of prepared glass frit and simulated waste glass samples: (1) The existence ratio of four coordinate sp structure (BO) tends to increase with increasing NaO content in glass samples. (2) The height of a pre-edge which appears by K-edge XANES spectrum of O is so high that the Fe content in glass samples. Following results were obtained by XAFS measurements of simulated waste glass samples after immersion test to investigate long chemical stability. (1) The existence ratio of four coordinate sp structure (BO) increases by immersion test. (2) Ce which exists in the surface layer is oxidized by immersion test, and much of Cs in surface layer is lost after leach testing. Even if the glass frit form (fiber cartridge or beads) and manufacturing method were changed and a glass sample of the similar chemical composition was prepared, these observed Raman spectra of samples were different.
Nagai, Takayuki; Okamoto, Yoshihiro; Akiyama, Daisuke*; Uehara, Akihiro*; Fujii, Toshiyuki*; Sekimoto, Shun*
KURNS Progress Report 2019, P. 257, 2020/08
To understand the influence of glass structural change by neutron irradiation and boron isotope composition, glass samples were made from enrichment boric acid reagents and neutron irradiation of those samples was carried out in Pn-2 of KUR. The structural change of glass sample after the irradiation will be estimated in 2020FY. Before neutron irradiation test of glass samples, the Si-O bridging structure difference by boron isotope composition compared by using a Raman spectrometry.
Abe, Yuta; Tsuchikawa, Yusuke; Kai, Tetsuya; Matsumoto, Yoshihiro*; Parker, J. D.*; Shinohara, Takenao; Oishi, Yuji*; Kamiyama, Takashi*; Nagae, Yuji; Sato, Ikken
Proceedings of 2020 International Conference on Nuclear Engineering (ICONE 2020) (Internet), 6 Pages, 2020/08
Nagai, Takayuki; Sasage, Kenichi; Okamoto, Yoshihiro; Shiwaku, Hideaki; Yamagishi, Hirona*; Ota, Toshiaki*; Inose, Takehiko*; Sato, Seiichi*; Hatakeyama, Kiyoshi*; Takahashi, Tomoe*; et al.
JAEA-Research 2019-003, 94 Pages, 2019/09
The local structures of glass-forming elements and waste elements would change by the chemical composition of waste glass including those elements. In this study, simulated waste glass samples were prepared from borosilicate glass frit including phosphorus (P) or vanadium (V), and we investigated local structures of boron, sodium, and waste elements in these P glass and V glass samples by using synchrotron XAFS measurements in soft and hard X ray region.
Shibata, Takanori*; Takagi, Akira*; Ikegami, Kiyoshi*; Sugimura, Takashi*; Nammo, Kesao*; Naito, Fujio*; Kobayashi, Hitoshi*; Kurihara, Toshikazu*; Honda, Yosuke*; Sato, Masaharu*; et al.
Proceedings of 15th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.385 - 387, 2018/10
Nagai, Takayuki; Kobayashi, Hidekazu; Shimamura, Keisuke; Oyama, Koichi; Sasage, Kenichi; Okamoto, Yoshihiro; Shiwaku, Hideaki; Yamanaka, Keisuke*; Ota, Toshiaki*
JAEA-Research 2018-005, 72 Pages, 2018/09
Addition of radioactive waste to a borosilicate glass frit affects the local structures of glass-forming elements and waste elements in a waste glass produced in a vitrification process. In this study, simulated waste glass samples were prepared from borosilicate glass frit including phosphorus pentaoxide, and we investigated local structures of sodium (Na), boron (B), and waste elements in these glass samples by using synchrotron XAFS measurements in soft and hard X ray region.
Nakajima, Kunihisa; Takai, Toshihide; Furukawa, Tomohiro; Osaka, Masahiko
Journal of Nuclear Materials, 491, p.183 - 189, 2017/08
Times Cited Count:8 Percentile:60.93(Materials Science, Multidisciplinary)One of the main chemical forms of cesium in the gas phase during severe accidents of light water reactor is expected to be cesium metaborate, CsBO, by thermodynamic equilibrium calculation considering reaction with boron. But accuracy of the thermodynamic data of gaseous metaborate, CsBO(g), has been judged as poor quality. Thus, Knudsen effusion mass spectrometric measurement of CsBO was carried out to obtain reliable thermodynamic data. The evaluated values of standard enthalpy of formation of CsBO(g), H(CsBO,g), by the 2nd and 3rd law treatments are -700.710.7 kJ/mol and -697.010.6 kJ/mol, respectively, and agree with each other within the errors, which suggests our data are reliable. Further, it was found that the existing data of the Gibbs energy function and the standard enthalpy of formation agreed well with the values evaluated in this study, which indicates the existing thermodynamic data are also reliable.
Nagai, Takayuki; Kobayashi, Hidekazu; Sasage, Kenichi; Ayame, Yasuo; Okamoto, Yoshihiro; Shiwaku, Hideaki; Yamanaka, Keisuke*; Ota, Toshiaki*
JAEA-Research 2017-005, 54 Pages, 2017/06
Addition of radioactive waste to a borosilicate frit affects the local structures of boron (B) and waste elements in a waste glass. Synchrotron XAFS measurement was applied to investigate the local structural changes by using simulated waste borosilicate glass samples. Following results were obtained by the B K-edge XAFS analysis. It was confirmed that B K-edge XAFS analysis enables us to discriminate sp type boron (BO) from sp type boron (BO). Addition of waste elements to a glass frit increases the percentage of BO and decreases that of BO. By decreasing the SiO/AlO ratio or increasing the (SiO+BO)/AlO ratio in the glass composition, the BO percentage increases and the BO percentage decreases. Addition of PO decreases the BO percentage and increases the BO percentage. Following results were obtained from XAFS measurement of the waste elements. Cerium (Ce) valence is more reduced with the increase of the BO content. Addition of PO has a tendency to reduce the Ce valence and to enhance deposition of Zr oxide. Deposition of ruthenium compounds separated from glass phase can not be improved by changing the BO content. This study was performed as a part of the project, "Improvement of vitrification process of high-level radioactive liquid wastes" on the foundation business of the Agency for Natural Resources and Energy.
Naito, Fujio*; Anami, Shozo*; Ikegami, Kiyoshi*; Uota, Masahiko*; Ouchi, Toshikatsu*; Onishi, Takahiro*; Oba, Toshiyuki*; Obina, Takashi*; Kawamura, Masato*; Kumada, Hiroaki*; et al.
Proceedings of 13th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1244 - 1246, 2016/11
The proton linac installed in the Ibaraki Neutron Medical Research Center is used for production of the intense neutron flux for the Boron Neutron Capture Therapy (BNCT). The linac consists of the 3-MeV RFQ and the 8-MeV DTL. Design average beam current is 10mA. Target is made of Beryllium. First neutron production from the Beryllium target was observed at the end of 2015 with the low intensity beam as a demonstration. After the observation of neutron production, a lot of improvement s was carried out in order to increase the proton beam intensity for the real beam commissioning. The beam commissioning has been started on May 2016. The status of the commissioning is summarized in this report.
Sato, Isamu; Onishi, Takashi; Tanaka, Kosuke; Iwasaki, Maho; Koyama, Shinichi
Journal of Nuclear Materials, 461, p.22 - 28, 2015/06
Times Cited Count:8 Percentile:55.87(Materials Science, Multidisciplinary)In order to evaluate B influence on the release and transport of Cs and I during severe accidents, basic experiments have been performed on the interaction between deposited Cs/I compounds and vapor/aerosol B compounds. CsI and BO were utilized as a Cs/I compound and a B compound, respectively. Deposited CsI on the thermal gradient tube (TGT), which is exposed to temperatures ranging from 423 K to 1023 K was reacted with vapor/aerosol BO, and then observed to determine how it changed Cs/I decomposition profiles. As a result, vapor/aerosol BO stripped a portion of deposited CsI within a temperature range from 830 K to 920 K to make gaseous CsBO and I. In addition, gaseous I was re-deposited at a temperature range from 530 K to 740 K, while CsBO travelled through the sampling tubes and filters without deposition. It is implied that B influences Cs carriers such as CsBO to transport Cs to the colder regions.