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Matsumura, Daiju; Kimura, Yusaku*; Tsuji, Takuya; Mizuki, Junichiro*
SPring-8/SACLA Riyo Kenkyu Seikashu (Internet), 11(5), p.296 - 299, 2023/11
no abstracts in English
Yomogida, Takumi; Ouchi, Kazuki; Oka, Toshitaka; Kitatsuji, Yoshihiro; Koma, Yoshikazu; Konno, Katsuhiro*
Scientific Reports (Internet), 12(1), p.7191_1 - 7191_10, 2022/05
Times Cited Count：4 Percentile：53.82(Multidisciplinary Sciences)Particles containing alpha (
) nuclides were identified from sediment in stagnant water at the torus room of the Fukushima Dai-ichi Nuclear Power Station (FDiNPS)'s Unit 2 reactor. Several uranium-bearing particles were identified by SEM observation. These particles contained Zr and other elements which constituted fuel cladding and structural materials. The 
U/
U isotope ratio in the solid fractions that included U particles was consistent with the nuclear fuel in the Unit 2 reactor, which indicated that the U particles had been derived from nuclear fuel. The particles with alpha-emitters detected by alpha track analysis were several tens to several hundred 
m in size. The EDX spectra showed that these particles mainly comprised iron, which indicated Pu, Am, and Cm were adsorbed on the Fe-baring particles. This study clarifies that the major morphologies of U and other -nuclides were differed in the sediment of stagnant water in the torus room of FDiNPS's Unit 2 reactor.
ion complex; Presence of a Rh
Intermediate in Direct PhotoreductionSaeki, Morihisa*; Matsumura, Daiju; Nakanishi, Ryuzo*; Yomogida, Takumi; Tsuji, Takuya; Saito, Hiroyuki*; Oba, Hironori*
Journal of Physical Chemistry C, 126(12), p.5607 - 5616, 2022/03
Times Cited Count：1 Percentile：14.66(Chemistry, Physical)The reaction mechanism of the direct photoreduction of a Rh ion complex to a Rh
species induced by pulsed ultraviolet laser irradiation was studied using dispersive X-ray absorption fine structure (DXAFS) spectroscopy. The time-resolved X-ray absorption near edge structure (XANES) showed the absence of isosbestic points and suggested that more than two Rh
species contribute toward the direct photoreduction of Rh. Analysis of the time-resolved XANES data by singular value deposition showed that the direct photoreduction involves three Rh species. Multivariate curve resolution by alternating least-squares analysis (MCR-ALS) of the time-resolved XANES data gave pure spectra and concentration profiles of the three Rh species. The Rh species were assigned to Rh, Rh, and Rh species based on the features of the pure XANES spectra. The concentration profiles suggested that the direct photoreduction proceeds in the order of Rh 
Rh Rh. A reaction mechanism, which was proposed involving photoreductions of Rh and Rh, photoinduced autocatalytic reductions of Rh and Rh, and photooxidation of Rh, well reproduced the concentration profiles of three Rh species.
Hidaka, Akihide
Proceedings of 2021 International Congress on Advances in Nuclear Power Plants (ICAPP 2021) (USB Flash Drive), 10 Pages, 2021/10
Author recently proposed that the Type A glassy Cesium-bearing microparticles that were released during the Fukushima accident may have been formed by melting and atomization of glass fibers of the High Efficiency Particulate Air (HEPA) filter in the Stand-by Gas Treatment System (SGTS) line in Unit 3 during the hydrogen explosion. In the present study, the components of the Type A and glass fibers of HEPA filter were examined using EPMA. The results showed that the components of the Type A were almost the same as that of the glass fibers except for Cs, Fe, Sn, which are considered to have been contained in the in-vessel-derived particles. When the glass fiber was irradiated with the electron beam of the Electron Probe Micro Analyzer (EPMA) under vacuum condition, spherical particles of a few micro m size were formed that looked very similar to the Type A. These strongly suggest that the HEPA filter is Si source of the Type A.
Hidaka, Akihide
Nihon Genshiryoku Gakkai-Shi ATOMO
, 63(9), p.679 - 680, 2021/09
no abstracts in English
Shirase, Mitsuyasu*; Abe, Akimasa*; Nago, Makito*; Ishii, Eiichi; Aoyagi, Kazuhei; Wakasugi, Shinichi*
Doboku Gakkai Heisei-29-Nendo Zenkoku Taikai Dai-72-Kai Nenji Gakujutsu Koenkai Koen Gaiyoshu (DVD-ROM), p.1795 - 1796, 2017/09
JAEA has executed the underground facility construction operation from February 2011 to June 2014, while carrying out the maintenance and research project until 2018. This report is about the extra high head pump which was able to drain the high specific gravity grout drainage, which develops during grouting operation at this facility, directly from 250m underground to the surface.
X-ray absorption spectroscopy study on water formation reaction of palladium metal nanoparticle catalystsMatsumura, Daiju; Taniguchi, Masashi*; Tanaka, Hirohisa*; Nishihata, Yasuo
International Journal of Hydrogen Energy, 42(11), p.7749 - 7754, 2017/03
Times Cited Count：5 Percentile：14.05(Chemistry, Physical)
O
studied by time-resolved XAFS using dispersive opticsMatsumura, Daiju; Okajima, Yuka*; Nishihata, Yasuo
Journal of Physics; Conference Series, 712(1), p.012042_1 - 012042_4, 2016/06
Times Cited Count：0 Percentile：0.03(Physics, Applied)
Pu/
U ratios in individual particles by ICP-MS without prior chemical separationEsaka, Fumitaka; Suzuki, Daisuke; Miyamoto, Yutaka; Magara, Masaaki
Microchemical Journal, 118, p.69 - 72, 2015/01
Times Cited Count：8 Percentile：29.03(Chemistry, Analytical)The determination of the time elapsed since the last purification of plutonium with chemical separation gives important information for monitoring nuclear activities related to reprocessing and nuclear weapon production. Although methods for the analysis of plutonium solutions have been extensively studied, few studies were conducted for the measurement of individual particles. In this work, a simple technique was developed for age determination of individual plutonium particles by a combination of single particle dissolution and measurement by inductively coupled plasma mass spectrometry (ICP-MS) without prior chemical separation. The analytical results of individual plutonium particles having an age of 5.98 y indicated that the use of Pu/U ratios allowed for the determination of accurate ages, though that of Pu/
U and 
Pu/U ratios was not suitable because of the contamination of natural uranium during the process of sample preparation.
Ozu, Akira; Okamoto, Ryuta*; Kawakita, Hiroshi*
Kurin Tekunoroji, 16(3), p.56 - 61, 2006/03
In recent years, particle counting devices capable of monitoring particles suspended in air on real-time basis are of considerable practical concern in the fields of semiconductor and large display panel industries. A remote particle counter, which had been developed for monitoring aerosols released in air from nuclear facilities, has been applied to a measurement system for clean rooms used in the fields. It can visualize the particles in narrow space at a distance of 6m and derive the number and size distribution of particles with diameter of above 0.5 microns. By improving the laser energy, sensitivity of the image intensifier camera, and magnification of the zoom lens used in the system, it is possible to detect the particles with diameters of below 0.5 microns. The method and the current performance of the measurement system are described.
Ozu, Akira
Genshiryoku eye, 51(11), p.68 - 71, 2005/11
In order to develop technologies for predicting and monitoring the atmospheric dispersion of aerosols containing radionuclides, a feasibility study on the real-time measurement of the aerosol being released into atmosphere from nuclear facilities has been conducted by using a laser radar technique. We have developed a remote particle counter capable of monitoring aerosol suspended in a distance space. The particle counter can measure the number and size of the aerosol on real-time basis. The performance of the counter was examined compared with that of conventional particle counters. It was found that aerosols with diameter of 
0.5 microns could be detected at a distance of 5 m. The technique is also applicable and useful for the aerosol monitoring in the other field such as semiconductor industries.
Ozu, Akira; Kawakita, Hiroshi*; Okamoto, Ryuta*
Proceedings of 7th International Congress on Optical Particle Characterization (OPC 2004) (CD-ROM), 5 Pages, 2004/00
Optical particle counters (OPCs) using laser light-scattering methods are widely used for aerosol research because they can provide accurate in situ measurements on real time basis. However, in general, it takes a few minutes to count the number of particles suspended in the air. As a novel method, we have developed a remote particle counter (RPC) using an imaging lidar technique, capable of determining with a single laser shot the number and size distribution of particles in the air several meters apart from the observation station. An experimental study has been conducted to calibrate the RPC system. The results obtained in the laboratory test are described compared to those with a conventional OPC using laser light-scattering methods. As the result,the real time measurement of the number and the histogram based on the size distribution of particles in air has been successfully demonstrated with the RPC system.
Yamaki, Tetsuya; Ito, Hisayoshi; Matsubara, Masakazu*; Abe, Hiroaki*; Asai, Keisuke*
Transactions of the Materials Research Society of Japan, 28(3), p.879 - 882, 2003/10
Titanium oxide nanoparticles were formed by pulsed laser ablation of a TiO rutile pellet with a KrF excimer laser (
= 248 nm). The ablation was performed in atmospheres of Ar and O at total pressures ranging from 0.2 and 10 Torr. At a higher pressure than 1 Torr, Ti in the nanoparticles had an oxidation state of 4+ to form TiO. According to the X-ray diffraction analyses, the nanopartiles were found to contain both the anatase and rutile phases, which crystallized through extremely energetic, non-equilibrium reactions in an ablation plume. In contrast, at pressures of 0.2 and 0.5 Torr, the nanoparticles were composed of dominant TiO with a small amount of a less oxidized phase such as TiO. The important result is that the XRD patterns of the samples prepared at 1 and 5 Torr showed the different anatase-to-rutile ratio of the peak intensities. This indicates that the weight fraction of the rutile/anatase crystalline phases can be controlled by the ambient gas pressure.
Abe, Hiroyuki; Kurata, Hiroki; Hojo, Kiichi
Journal of the Physical Society of Japan, 69(5), p.1553 - 1557, 2000/05
Times Cited Count：4 Percentile：38.21(Physics, Multidisciplinary)no abstracts in English
Oda, Yoshihiro; Funasaka, Hideyuki; Wang, X.*; Obara, Kenji*; Wada, Hitoshi*
JNC TY8400 2000-002, 47 Pages, 2000/03
JNC-TY8400-2000-002.pdf:2.53MB
no abstracts in English
Takase, Kazuyuki; Kunugi, Tomoaki*
Proc. of 5th ASME/JSME Joint Thermal Engineering Conf. (CD-ROM), 8 Pages, 1999/00
no abstracts in English
; *; Hirabayashi, Takakuni; Aoki, Kazuhiro
Proc. of 1998 JAIF Int. Conf. on Water Chemistry in Nucl. Power Plants (Water Chemistry'98), p.566 - 570, 1998/00
no abstracts in English
Bottcher, J. T.
PNC TN9440 97-011, 215 Pages, 1997/06
J.H.Bottcher started his intemational Fellow position at PNC on March 25, 1996.During his 15 months in PNC he worked in the Irradiation Section of the Experimental Reactor Division. There he worked on conceptual design reviews and related the US irradiations methodology to the members. His work extended to other Divisions at OEC and Tokai Works, mainly related to fuel development and irradiation performance. In these efforts he published two papers, wrote a desip review document, and presented six lectures on irradiated fuels and materials. In addition he participated in coordinating a new four year PNC/DOE collaborative program on irradiated steels characterization.
