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Sr in environmental samples utilizing laser photo-detachmentHonda, Maki; Martschini, M.*; Marchhart, O.*; Steier, P.*; Golser, R.*; Sakaguchi, Aya*
Hoshasen (Internet), 48(4), p.130 - 136, 2024/02
Strontium-90 (Sr, 28.9 years) is a key fission product nuclide in internal dose assessment because it accumulates in bones and teeth in the body, causing health problems. Therefore, it is essential to know the distribution of Sr in the environment and its temporal variation (Sr enrichment in biota), which requires efficient analysis of many environmental samples. An analysis of environmental samples with known Sr concentrations conducted with the 3 MV AMS facility (VERA: Vienna Environmental Research Accelerator) at the University of Vienna, Austria, towards the practical application of Sr AMS, the results of which are detailed in this paper. In this study, the validity of the AMS method was demonstrated by analyzing environmental samples with known Sr concentrations (IAEA-447, IAEA-A-12, and IAEA-TEL-2015-03 sample 5: 1 dry-g each). The chemical separation developed in this study takes approximately two days and is a more straightforward procedure than conventional 
-ray detection methods. The Sr measurements were conducted on the AMS system combined with the Ion Laser InterAction Mass Spectrometry (ILIAMS) system. The AMS method achieved a limit of detection 
0.1 mBq ( 1.3
10
atoms) for Sr, which is 1/30th of typical -ray detection. As a result of the lower detection limit, the AMS method allows Sr quantification with smaller sample volumes. For example, a Japanese freshwater sample with a Sr concentration of 4 mBq/L requires a sample volume of 5 liter
Tamakuma, Yuki*; Yamada, Ryohei; Iwaoka, Kazuki*; Hosoda, Masahiro*; Kuroki, Tomohiro*; Mizuno, Hiroyuki*; Yamada, Koji*; Furukawa, Masahide*; Tokonami, Shinji*
Perspectives in Science (Internet), 12, p.100414_1 - 100414_4, 2019/09
In this study, a portable radioactive plume monitor using a silicon photodiode was developed for the detection of a radioactive plume (e.g. 
I, 
Cs and 
Cs) in an emergency situation. It was found that the background count rate was proportional to ambient dose equivalent rate and the detection limit for the monitor at 20 
Sv h
as an ambient dose equivalent rate was evaluated to be 187 Bq m
using the ISO11929 method. These results suggest that the detection limit for the system can be decreased effectively by lead shielding with optimized thickness.
Narukawa, Takafumi
Kaku Nenryo, (54-2), P. 3, 2019/07
no abstracts in English
Uesawa, Shinichiro; Ono, Ayako; Koizumi, Yasuo; Shibata, Mitsuhiko; Yoshida, Hiroyuki
Nihon Kikai Gakkai Netsu Kogaku Konfuarensu 2018 Koen Rombunshu (USB Flash Drive), 6 Pages, 2018/10
no abstracts in English
Narukawa, Takafumi
Kaku Nenryo, (53-2), P. 5, 2018/08
no abstracts in English
Uesawa, Shinichiro; Ono, Ayako; Koizumi, Yasuo; Shibata, Mitsuhiko; Yoshida, Hiroyuki
Dai-55-Kai Nihon Dennetsu Shimpojiumu Koen Rombunshu (USB Flash Drive), 8 Pages, 2018/05
no abstracts in English
Amaya, Masaki; Udagawa, Yutaka; Narukawa, Takafumi; Mihara, Takeshi; Taniguchi, Yoshinori
Proceedings of Annual Topical Meeting on LWR Fuels with Enhanced Safety and Performance (TopFuel 2016) (USB Flash Drive), p.53 - 62, 2016/09
In order to evaluate adequacy of present safety criteria and safety margins in terms of advanced fuels and provide a database for future regulation on them, JAEA started an extensive research program called ALPS-II program, which has been sponsored by NRA, Japan. This program is primarily composed of tests simulating a RIA and a LOCA on the high-burnup advanced fuels irradiated in commercial PWR or BWR. Recently, the failure limits of the high-burnup advanced fuels under RIA conditions were investigated at NSRR, and post-test examinations on the fuel rods after the pulse irradiation tests are being performed. In terms of the simulated LOCA test, integral thermal shock tests and high temperature oxidation tests were carried out at RFEF, and the fracture limits, high temperature oxidation rate, etc. of the high-burnup advanced fuel cladding were investigated. This paper mainly describes some recent experimental results obtained in this program with respect to RIA and LOCA.
Liu, W.
Dai-20-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu, p.391 - 392, 2015/06
Subcooled flow boiling is a boiling that begins and develops even though the mean enthalpy of liquid phase is lower than saturation. This forced convective boiling is one of the most efficient ways for the removal of high heat flux. It is widely used in the high heat flux components such as nuclear reactor cores, accelerator targets and fusion reactor components. The thermal outputs of these systems are restricted by Critical Heat Flux(CHF). Because of the importance of the CHF, lots of researches, including both experimental and mechanistic modelling, have been performed. However, the CHF prediction for rod bundles still remains unsolved. As the first step for the CHF prediction in rod bundles, in this paper, we tried to predict the CHF in annulus, which is the most basic flow geometry simplified from a rod bundle. We performed the CHF prediction by using liquid sublayer dryout model, combined with Nouri single phase velocity distribution correlation for annulus. The results show that the CHF in annulus can be predicted in an accuracy of about 
20%.
Tamai, Hidesada; Onuki, Akira; Kureta, Masatoshi*; Liu, W.; Sato, Takashi; Akimoto, Hajime
Proceedings of 2005 International Congress on Advances in Nuclear Power Plants (ICAPP '05) (CD-ROM), 8 Pages, 2005/05
no abstracts in English
Tamai, Hidesada; Yoshida, Hiroyuki; Masuko, Kenji*; Akimoto, Hajime
Proceedings of 4th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-4), p.230 - 236, 2004/12
no abstracts in English
analyses with ferromagnetic and plasma rotation effects and wall geometry for a high steady state tokamakKurita, Genichi; Bialek, J.*; Tsuda, Takashi; Azumi, Masafumi; Ishida, Shinichi; Navratil, G. A.*; Sakurai, Shinji; Tamai, Hiroshi; Matsukawa, Makoto; Ozeki, Takahisa; et al.
IAEA-CN-116/FT/P7-7 (CD-ROM), 8 Pages, 2004/11
The critical beta is shown to be decreased by ferromagnetic effect by about 8 % for m/m0
2, m and m0 denote the permeability of ferromagnetic wall and vacuum, respectively, for tokamak of aspect ratio 3. The existence of the stability window opened by both effects of the toroidal plasma rotation and the plasma dissipation, which was not observed for high aspect ratio tokamak, is found for tokamak of aspect ratio 3. The effect of ferromagnetism on them is also investigated. The critical beta analyses of NCT (National Centralized Tokamak) plasma using VALEN code are started with stabilizing plate and vacuum vessel geometry with finite resistivity, and the results for passive effect of stabilizing plate are obtained. The calculations including stabilizing effect of the vacuum-vessel and also active feedback control are also performed for present design of NCT plasma.
Sugiyama, Tomoyuki; Fuketa, Toyoshi
Journal of Nuclear Science and Technology, 41(11), p.1083 - 1090, 2004/11
Times Cited Count：10 Percentile：55.55(Nuclear Science & Technology)The effect of cladding surface pre-oxidation on the rod coolability under reactivity initiated accidents was investigated. NSRR tests on irradiated fuel rods have shown higher rod coolability than that of fresh rods, which arose from suppressed DNB and early quench at the surface. To identify the dominant factor, possible factors such as pellet cracking and so on, were assessed. The most probable factor, the cladding pre-oxidation, was examined by pulse irradiation tests on fresh rods with three cladding surface conditions, no oxide layer, 1m and 10m-thick oxide layers. Temperature measurements showed increased thresholds for DNB and quench at the pre-oxidized surface, leading to a reduced film boiling duration. The shifts of the critical and minimum heat flux points could be caused by the surface wettability increase. In the present tests, the wettability change was probably dominated by the chemical potential change at the surface due to pre-oxidation. The test results indicate the effects do not depend on the oxide layer thickness, but on the presence of the oxide layer.
Nagashima, Keisuke; Tanaka, Momoko; Nishikino, Masaharu; Kishimoto, Maki; Kado, Masataka; Kawachi, Tetsuya; Hasegawa, Noboru; Ochi, Yoshihiro; Sukegawa, Kota*; Tai, R.; et al.
Applied Physics B, 78(7), p.927 - 932, 2004/05
We have succeeded in developing a laser-pumped X-ray laser with full spatial coherence at 13.9 nm. A highly directed X-ray laser beam with the divergence of 0.2 mrad was generated from the double target experiment, where a seeding light from the first laser medium was amplified in the second medium. The observed divergence is close to the diffraction limit value within a factor of two. The seeding light was amplified in the second medium without refraction influence and the gain coefficient was about 8 cm-1. From the measurement of visibility, it was found that the spatial coherent length is longer than the beam diameter. As an application of this coherent X-ray laser, we observed a surface microstructure of ferroelectric material, BaTiO
and clarified a change of the microstructure near the Curie temperature.
Nagashima, Keisuke; Tanaka, Momoko; Nishikino, Masaharu; Kishimoto, Maki; Kado, Masataka; Kawachi, Tetsuya; Hasegawa, Noboru; Ochi, Yoshihiro; Sukegawa, Kota*; Tai, R.
Purazuma, Kaku Yugo Gakkai-Shi, 80(3), p.236 - 240, 2004/03
A laser-pumped X-ray laser with full spatial coherence has been developed for the first time. This X-ray laser has the wavelength of 13.9 nm and the beam divergence of 0.2 mrad. In the experiment, a seeding light from the first laser medium was amplified in the second medium, which worked as an active spatial filter. The observed beam divergence was close to the diffraction limited value within a factor of two. The seeding light was amplified in the second medium without refraction influence. The gain region of the second medium was far away from the target surface compared with that of the first medium and located in the considerably low density region. From the measurement of visibility, it was found that the spatial coherent length is longer than the beam diameter. It means that this X-ray laser beam is full spatial coherent.
Tanaka, Momoko; Nishikino, Masaharu; Kawachi, Tetsuya; Hasegawa, Noboru; Kado, Masataka; Kishimoto, Maki; Nagashima, Keisuke; Kato, Yoshiaki
Optics Letters, 28(18), p.1680 - 1682, 2003/09
Times Cited Count：64 Percentile：90.03(Optics)We have demonstrated an x-ray laser at a wavelength of 13.9 nm with a beam divergence of 0.2 mrad, which is 1.8 times the diffraction limit. The x-ray laser is generated using two gain media, where the seed x-ray pulse from the first medium is amplified in the second medium. The effect of refraction on x-ray propagation is reduced by spatially and temporally controlling the injection of the seed x-ray to the second medium.
Kureta, Masatoshi; Akimoto, Hajime
Nuclear Technology, 143(1), p.89 - 100, 2003/07
Times Cited Count：10 Percentile：56.31(Nuclear Science & Technology)no abstracts in English
Kureta, Masatoshi; Akimoto, Hajime
Nihon Kikai Gakkai Rombunshu, B, 69(682), p.1469 - 1476, 2003/06
no abstracts in English
Monde, Masanori*; Mitsutake, Yuichi*; Ishida, Kenji*; Hino, Ryutaro
JAERI-Tech 2003-013, 56 Pages, 2003/03
no abstracts in English
Kureta, Masatoshi; Hibiki, Takashi*; Mishima, Kaichiro*; Akimoto, Hajime
International Journal of Heat and Mass Transfer, 46(7), p.1171 - 1181, 2003/03
Times Cited Count：13 Percentile：49.06(Thermodynamics)no abstracts in English
Nakano, Yoshihiro; Ishikawa, Nobuyuki; Nakatsuka, Toru; Iwamura, Takamichi
JAERI-Conf 2002-012, 219 Pages, 2002/12
JAERI-Conf-2002-012.pdf:17.4MB
no abstracts in English
