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Hirooka, Shun; Horii, Yuta; Sunaoshi, Takeo*; Uno, Hiroki*; Yamada, Tadahisa*; Vauchy, R.; Hayashizaki, Kohei; Nakamichi, Shinya; Murakami, Tatsutoshi; Kato, Masato
Journal of Nuclear Science and Technology, 60(11), p.1313 - 1323, 2023/11
Times Cited Count：3 Percentile：95.99(Nuclear Science & Technology)Additive MOX pellets are fabricated by a conventional dry powder metallurgy method. Nd
O
and SmO are chosen as the additive materials to simulate the corresponding soluble fission products dispersed in MOX. Shrinkage curves of the MOX pellets are obtained by dilatometry, which reveal that the sintering temperature is shifted toward a value higher than that of the respective regular MOX. The additives, however, promote grain growth and densification, which can be explained by the effect of oxidized uranium cations covering to a pentavalent state. Ceramography reveals large agglomerates after sintering, and Electron Probe Micro-Analysis confirms that inhomogeneous elemental distribution, whereas XRD reveals a single face-centered cubic phase. Finally, by grinding and re-sintering the specimens, the cation distribution homogeneity is significantly improved, which can simulate spent nuclear fuels with soluble fission products.
Hidaka, Akihide
Nuclear Technology, 208(2), p.318 - 334, 2022/02
Times Cited Count：5 Percentile：65.59(Nuclear Science & Technology)The author previously proposed that the Cs bearing microparticle (Type A) may have been formed by melting and atomization of glass fibers (GF) of the HEPA filter in the SGTS due to flame and blast during the hydrogen explosion in Unit 3. If this hypothesis is correct, the Type A could contain or accompany carbon (C), that ignites spontaneously above 623 K, because of the limited time to be heated up, inclusion of C in the binder applied on the GF surface and closely located charcoal filter. As the previous studies did not focus on C, the present analyses were performed with EPMA whether the Type A contains C. The results showed that the Type A contained C originating from the binder, and non-spherical particles accompanied by the Type A and the film surrounding the Type A contained more C, which is thought to originate from the charcoal filter. These results cannot be explained by the other mechanisms proposed so far, and can be explained consistently by the author proposed hypothesis.
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.
Kakiuchi, Kazuo; Udagawa, Yutaka; Amaya, Masaki
Annals of Nuclear Energy, 155, p.108171_1 - 108171_11, 2021/06
Times Cited Count：1 Percentile：16.35(Nuclear Science & Technology)Yonaga, Yusuke; Sano, Naomi*; Amamiya, Hiroki*; Ogita, Yasuhiro; Niwa, Masakazu; Yasue, Kenichi*
Oyo Chishitsu, 62(1), p.2 - 12, 2021/04
Provenance analysis based on quick identification of heavy minerals using an electron probe microanalyzer (EPMA) was applied to samples from Pleistocene sediments in Horonobe region, Hokkaido, where major provenance rocks can be sedimentary and mafic igneous rocks. The concentrations of 16 elements were measured in individual grains to identify the mineral species based on their chemical composition. In addition, microscopic observation of thin sections and gravel composition analysis were conducted to confirm the validity of the quick identification of heavy minerals. These analyses clarify that combinations of several heavy mineral species can be a useful index of provenance rocks from the Soya Hill and Teshio Mountains, and suggest that uplift of the Soya Hill after ca. 1.5 Ma constrained supply of sediments from the Teshio Mountains. On the other hand, minerals uncommon both in the Soya Hill and Teshio Mountains, such as hornblende, are included in the Pleistocene sediments. This suggests that a sediment supply from distant area was also significant, like transportation by the Teshio River. The method for quick identification of heavy minerals using EPMA can provide an information about provenance rocks difficult to identify only by gravel composition analysis.
Nakayama, Masashi
JAEA-Data/Code 2020-009, 98 Pages, 2020/09
JAEA-Data-Code-2020-009.pdf:6.06MB
JAEA-Data-Code-2020-009-appendix1(DVD-ROM).zip:172.11MBJAEA-Data-Code-2020-009-appendix2-1(DVD-ROM).zip:468.85MBJAEA-Data-Code-2020-009-appendix2-2(DVD-ROM).zip:102.94MBJAEA-Data-Code-2020-009-appendix2-3(DVD-ROM).zip:141.88MBJAEA-Data-Code-2020-009-appendix2-4(DVD-ROM).zip:141.6MB
Japan Atomic Energy Agency (JAEA) has developed a low alkaline cement, named as HFSC (Highly Fly-ash contained Silicafume Cement), in order to decrease the effect on geological environment of cementitious material. HFSC was used experimentally as the shotcrete (140m, 250m and 350m depth gallery) and lining concrete (GL-374m to GL-380m of east access shaft) in construction part of Horonobe URL. In order to evaluate the effect of HFSC on the surrounding rock and groundwater, concrete and rock cores were periodically sampled from the site where the in-situ construction test was conducted, and various analyzes were conducted. Ordinary Portland Cement (OPC) was used for part of 140m depth gallery, and the same analysis as HFSC was conducted, in order to compare the effect of OPC and HFSC. This report summarizes the results of analyzes conducted on core samples from 2009 to 2018.
Ogino, Masataka*; Owaki, Eiji*; Shirase, Mitsuyasu*; Nakayama, Masashi
Konkurito Kogaku Nenji Rombunshu (DVD-ROM), 39(1), p.703 - 708, 2017/07
no abstracts in English
Shimizu, Mayuko; Sano, Naomi; Suzuki, Kazuhiro
Nagoya Daigaku Nendai Sokutei Kenkyu, 1, p.36 - 43, 2017/03
We established a CHIME monazite dating method using R
= 100 mm spectrometers and a provenance analysis method using heavy minerals for the dating and analysis of minerals. CHIME dating has traditionally been performed with conventional R = 140 mm spectrometers for measurement of U, Th, and Pb. These spectrometers, however, have low count rates in measurements of Pb. We used a JEOL JXA-8530F FE-EPMA equipped with R = 100 mm spectrometers, a system installed at Tono Geoscience Center in 2014, for the CHIME dating of monazite. We corrected the spectral interferences peculiar to R = 100 mm spectrometers by the method of AA mli and Griffin (1975) for monazite analyses. We calculated the correction factors by a new interference correction method using natural monazites. We also established a quick quantitative analysis and identification method for heavy minerals using the EPMA.
Sasaki, Shinji; Tanno, Takashi; Maeda, Koji
Proceedings of 54th Annual Meeting of Hot Laboratories and Remote Handling (HOTLAB 2017) (Internet), 6 Pages, 2017/00
During irradiation in a fast reactor, the microstructure change of the mixed oxide fuels and the changes of element distributions occur because of a radial temperature gradient. Therefore, it is important to study the irradiation behavior of MA-MOX for advancement of fast reactor fuels. In order to make detailed observations of microstructure and elemental analyses of MA-MOX, irradiated MA-MOX specimens were carried out PIE by using a FE-SEM equipped with WDX. Because fuel samples have high radio activities and emit alpha-particles, the instrument was modified. the instrument was installed in a lead shield box and the control unit was separately located outside the box. The microstructure changes were observed in irradiated MA-MOX specimen. The characteristic X-rays peaks were detected successfully. By measuring the intensities of characteristic X-rays, it was tried quantitative analysis of U, Pu, Am along radial direction of irradiated specimen.
Shibata, Kenji; Shimizu, Mayuko; Suzuki, Kazuhiro
Nagoya Daigaku Kasokuki Shitsuryo Bunsekikei Gyoseki Hokokusho, 26, p.126 - 131, 2015/03
no abstracts in English
fuel at burnup of 45 GWd/t during simulated Reactivity Initiated Accident (RIA) conditionAmaya, Masaki; Sugiyama, Tomoyuki; Fuketa, Toyoshi
Journal of Nuclear Science and Technology, 41(10), p.966 - 972, 2004/10
Times Cited Count：7 Percentile：45.11(Nuclear Science & Technology)Pulse irradiation simulating RIA condition was carried out for test rod prepared from fuel irradiated in a commercial reactor. After the pulse irradiation, optical microscopy (OM) and scanning electron microscopy (SEM) observations and electron probe micro analysis (EPMA) were conducted for the test rod as a part of destructive tests. Fission gas release behavior during pulse irradiation was investigated by EPMA and puncture test. Xeon depression was observed in the fuel pellet after pulse irradiation at periphery and center region. It is considered that fission gas was mainly released from the pellet center region during pulse irradiation. The amount of xenon release during pulse irradiation was estimated to be 10-12% from the EPMA results and this estimated value was comparable with the puncture test result. Comparing the estimated value with other results of out-of-pile annealing tests, it was concluded that most fission gas, which was accumulated at grain boundary during base irradiation, was released from the center region of test fuel pellet during pulse irradiation.
Furusawa, Takayuki; Sumita, Junya; Ueta, Shohei; Nemoto, Takahiro; Oyama, Sunao*; Kamata, Takashi
JAERI-Tech 2004-024, 46 Pages, 2004/03
JAERI-Tech-2004-024.pdf:6.75MB
Primary helium circulators of the HTTR are the important component as the helium gas which is reactor coolant, and three circulators for the primary pressurized water cooler and one for the intermediate heat exchanger are installed in primary cooling system. In the upstream of these circulators, the filter has been installed in order to suppress that it is entrapped in the bearing in which fine particles in helium gas, support main shaft of the helium circulator. The differential pressure of this filter rose gradually during rise-to-power test. The rise of the filter differential pressure of the helium circulator may cause the problem for reactor operation. Therefore, the filters were newly manufactured, and replacement of the filter was carried out. In replacement of the filter, appearance confirmation was carried out and deposit of the filter was analyzed. This paper described replacement of the filter and filter differential pressure rise investigation of the causes.
Onuma, Ikuo*; Kainuma, Ryosuke*; Uda, Minoru*; Iwadachi, Takaharu*; Uchida, Munenori*; Kawamura, Hiroshi; Ishida, Kiyohito*
JAERI-Conf 2004-006, p.172 - 183, 2004/03
no abstracts in English
Iizuka, Masatoshi*; Uozumi, Koichi*; Inoue, Tadashi*; Iwai, Takashi; Shirai, Osamu; Arai, Yasuo
Journal of Nuclear Materials, 299(1), p.32 - 42, 2001/10
Times Cited Count：76 Percentile：97.56(Materials Science, Multidisciplinary)no abstracts in English
Esaka, Fumitaka; Watanabe, Kazuo; Magara, Masaaki; Hanzawa, Yukiko; Usuda, Shigekazu; Gunji, Katsubumi; Nishimura, Hideo; Adachi, Takeo
Proceedings of 12th International Conference on Secondary Ion Mass Spectrometry (SIMS 12), p.977 - 980, 2000/00
no abstracts in English
*; Obara, Kenjiro; Tada, Eisuke; Morita, Yosuke; Yagi, Toshiaki; *
JAERI-Tech 99-029, 36 Pages, 1999/03
no abstracts in English
Kameo, Yutaka
Proceedings of OECD/NEA Workshop on Evaluation of Speciation Technology, p.241 - 245, 1999/00
no abstracts in English
-phase compositionsAkabori, Mitsuo; Ito, Akinori; Ogawa, Toru; *
Journal of Alloys and Compounds, 271-273, p.597 - 601, 1998/00
Times Cited Count：15 Percentile：66.67(Chemistry, Physical)no abstracts in English
*; *; *; *; Nakahara, Hiromichi*; Nakada, Masami; Saeki, Masakatsu; Aratono, Yasuyuki
Hyperfine Interactions, 91, p.645 - 649, 1994/00
Times Cited Count：2 Percentile：20.81(Physics, Atomic, Molecular & Chemical)no abstracts in English
Arai, Yasuo; Maeda, Atsushi; Shiozawa, Kenichi; Omichi, Toshihiko
Journal of Nuclear Materials, 210, p.161 - 166, 1994/00
Times Cited Count：29 Percentile：89.83(Materials Science, Multidisciplinary)no abstracts in English
