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Miyahara, Naoya; Miwa, Shuhei; Horiguchi, Naoki; Sato, Isamu*; Osaka, Masahiko
Journal of Nuclear Science and Technology, 56(2), p.228 - 240, 2019/02
Times Cited Count:8 Percentile:61.05(Nuclear Science & Technology)In order to improve LWR source term under severe accident conditions, the first version of a fission product (FP) chemistry database named "ECUME" was developed. The ECUME is intended to include major chemical reactions and their effective kinetic constants for representative SA sequences. It is expected that the ECUME can serve as a fundamental basis from which FP chemical models in the SA analysis codes can be elaborated. The implemented chemical reactions in the first version were those for representative gas species in Cs-I-B-Mo-O-H system. The chemical reaction kinetic constants were evaluated from either literature data or calculated values using ab-initio calculations. The sample chemical reaction calculation using the presently constructed dataset showed meaningful kinetics effects at 1000 K. Comparison of the chemical equilibrium compositions by using the dataset with those by chemical equilibrium calculations has shown rather good consistency for the representative Cs-I-B-Mo-O-H species. From these results, it was concluded that the present dataset should be useful to evaluate FP chemistry in Cs-I-B-Mo-O-H system under LWA SA conditions.
Hatsukawa, Yuichi*; Hayakawa, Takehito*; Tsukada, Kazuaki; Hashimoto, Kazuyuki*; Sato, Tetsuya; Asai, Masato; Toyoshima, Atsushi; Tanimori, Toru*; Sonoda, Shinya*; Kabuki, Shigeto*; et al.
PLOS ONE (Internet), 13(12), p.e0208909_1 - e0208909_12, 2018/12
Times Cited Count:3 Percentile:26.77(Multidisciplinary Sciences)Imaging of Tc radioisotope was conducted using an electron tracking-Compton camera (ETCC).
Tc emits 204, 582, and 835 keV
rays, and was produced in the
Mo(p,n)
Tc reaction with a
Mo-enriched target. The recycling of the
Mo-enriched molybdenum trioxide was investigated, and the recycled yield of
Mo was achieved to be 70% - 90%. The images were obtained with each of the three
rays. Results showed that the spatial resolution increases with increasing
-ray energy, and suggested that the ETCC with high-energy
-ray emitters such as
Tc is useful for the medical imaging of deep tissue and organs in the human body.
Di Lemma, F. G.; Yamashita, Shinichiro; Miwa, Shuhei; Nakajima, Kunihisa; Osaka, Masahiko
Energy Procedia, 127, p.29 - 34, 2017/09
Times Cited Count:5 Percentile:92.26(Energy & Fuels)Chemical effects of molybdenum (Mo) and boron (B), which were considered to form compounds with Cs, on the Cs chemisorption were predicted using a chemical equilibrium calculation. It is seen that CsMoO
were formed in the chemisorbed compounds. On the other hand, little effects were observed for B. The results suggest that the effects of Mo should be considered for further experimental investigation.
Eichler, R.*; Asai, Masato; Brand, H.*; Chiera, N. M.*; Di Nitto, A.*; Dressler, R.*; Dllmann, Ch. E.*; Even, J.*; Fangli, F.*; Goetz, M.*; et al.
EPJ Web of Conferences, 131, p.07005_1 - 07005_7, 2016/12
Times Cited Count:3 Percentile:72.00(Chemistry, Inorganic & Nuclear)In recent years gas-phase chemical studies assisted by physical pre-separation allowed for the productions and investigations of fragile single molecular species of superheavy elements. The latest highlight is the formation of very volatile hexacarbonyl compound of element 106, Sg(CO). Following this success, second-generation experiments were performed to measure the first bond dissociation energy between the central metal atom and the surrounding ligand. The method using a tubular decomposition reactor was developed and successfully applied to short-lived Mo(CO)
, W(CO)
, and Sg(CO)
.
Fukui, Toshiki*; Maki, Takashi*; Miura, Nobuyuki; Tsukada, Takeshi*
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 23(2), p.169 - 173, 2016/12
The basic research programs for the next generation vitrification technology, which are commissioned project from Ministry of Economy, Trade and Industry of Japan, have been implemented from 2014 until 2018 for developing the advanced vitrification technology of low level wastes and high level liquid wastes.
Usoltsev, I.*; Eichler, R.*; Wang, Y.*; Even, J.*; Yakushev, A.*; Haba, Hiromitsu*; Asai, Masato; Brand, H.*; Di Nitto, A.*; Dllmann, Ch. E.*; et al.
Radiochimica Acta, 104(3), p.141 - 151, 2016/03
Times Cited Count:34 Percentile:94.45(Chemistry, Inorganic & Nuclear)Conditions of the production and decomposition of hexacarbonyl complexes of short-lived Mo and W isotopes were investigated to study thermal stability of the heaviest group 6 hexacarbonyl complex Sg(CO). A tubular flow reactor was tested to decompose the hexacarbonyl complexes and to extract the first bond dissociation energies. A silver was found to be the most appropriate reaction surface to study the decomposition of the group 6 hexacarbonyl. It was found that the surface temperature at which the decomposition occurred was correlated to the first bond dissociation energy of Mo(CO)
and W(CO)
, indicating that the first bond dissociation energy of Sg(CO)
could be determined with this technique.
Sato, Takumi; Shibata, Hiroki; Hayashi, Hirokazu; Takano, Masahide; Kurata, Masaki
Journal of Nuclear Science and Technology, 52(10), p.1253 - 1258, 2015/10
Times Cited Count:7 Percentile:48.66(Nuclear Science & Technology)In order to explore the applicability of the chlorination by MoCl as a potential pretreatment technique for waste treatment of fuel debris by pyrochemical methods, chlorination experiments of UO
and (U
Zr
)O
simulated fuel debris were carried out in two steps: the first one is a chlorination reaction by homogeneous heating, the second one is a volatilization of molybdenum by-product by heating under temperature gradient condition. Most of UO
and (U
Zr
)O
powder were converted to UCl
or UCl
and ZrCl
mixture at 573 K, respectively. In the case of (U
Zr
)O
sintered particle, most of sample was converted to the chlorides because the products evaporated and be separated from sample surface at 773 K, while only the surface of the sample disk was converted to the chlorides at 573 and 673 K. Most of molybdenum by-product and ZrCl
were separated from UCl
by volatilization at 573 K.
Sugie, Tatsuo; Kasai, Satoshi; Taniguchi, Masaki; Nagatsu, Masaaki*; Nishitani, Takeo
Journal of Nuclear Materials, 329-333(2), p.1481 - 1485, 2004/08
Times Cited Count:30 Percentile:85.32(Materials Science, Multidisciplinary)In ITER, the effect of lower energy particle bombardment is important for mirrors located near the divertor where the low temperature plasma is formed. The test pieces of molybdenum mirrors and a tungsten mirror were irradiated by high flux and low energy (67-80 eV) deuterium ions using SLEIS (Super Low Energy Ion Source with High Ion Flux) facility at the temperature of around 100 C. The molybdenum mirror manufactured by sintering and melting the thin layer of the surface by electron beam in order to eliminate holes on the surface has a higher reflectivity before irradiation than the mirrors without melting the surface, but the reflectivity decreases rapidly with the irradiation fluence due to the generation of blisters on the mirror surface. The reflectivity of molybdenum mirror manufactured by sintering only did not decrease so significantly (less than 10 % at the fluence of 1.3
10
m
). The molybdenum and tungsten mirrors manufactured by sintering without melting the surface have a potential for plasma facing mirrors in ITER.
Shirai, Osamu; Uozumi, Koichi*; Iwai, Takashi; Arai, Yasuo
Journal of Applied Electrochemistry, 34(3), p.323 - 330, 2004/03
Times Cited Count:29 Percentile:53.05(Electrochemistry)The electrode reactions of the Np/Np couple at liquid Cd and Bi electrodes were investigated by cyclic voltammetry at 723, 773 and 823 K in LiCl-KCl eutectic melt. It was found that the diffusion of Np
in the salt phase was a rate-determining step in the cathodic reaction when the concentration of NpCl
was less than about 1 wt.% and the liquid Cd or Bi phase was not saturated with Np. The redox potentials of the Np
/Np couple at liquid Cd electrode at 723, 773 and 823 K were observed more positively than those at Mo electrode by 0.158, 0.140 and 0.126 V, respectively. The potential shift would result from a lowering of activity of Np in Cd phase according to the alloy formation of NpCd
at 723 K and NpCd
at 773 and 823 K. The redox potentials of the Np
/Np couple at liquid Bi electrode at 723, 773 and 823 K were more positive than those at Mo electrode by 0.427, 0.419 and 0.410 V, respectively, which would be attributable to a lowering of activity of Np in Bi phase according to the formation of NpBi
.
Nemoto, Yoshiyuki; Hasegawa, Akira*; Sato, Manabu*; Abe, Katsunori*; Hiraoka, Yutaka*
Journal of Nuclear Materials, 324(1), p.62 - 70, 2004/01
Times Cited Count:49 Percentile:92.77(Materials Science, Multidisciplinary)In this study, stress-relieved specimens and recrystallized specimens of pure Mo and Mo-Re alloys (Re content=2,4,5,10,13 and 41wt%) were neutron irradiated up to 20dpa at various temperatures (681-1072K). On microstructure observation, sigma phase and chi phase precipitates were observed in all irradiated Mo-Re alloys. Voids were observed in all irradiated specimen, and dislocation loops and dislocations were observed in the specimens that were irradiated at lower temperatures. On Vickers hardness testing, all of the irradiated specimens showed hardening. Especially Mo-41Re were drastically embrittled after irradiation at 874K or less. From these results, authors discuss about relation between microstructure development and radiation hardening, embrittlement, and propose the most efficient Re content and thermal treatment for Mo-Re alloys to be used under irradiation condition.
Wu, G.; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao
Journal of Synchrotron Radiation, 8(Part.2), p.469 - 471, 2001/03
no abstracts in English
Yanagihara, Satoshi; ; Nakamura, Hisashi
Nuclear Technology, 86, p.159 - 167, 1989/08
Times Cited Count:3 Percentile:41.59(Nuclear Science & Technology)no abstracts in English
Sasaki, Shigemi; Iwase, Akihiro
Nuclear Instruments and Methods in Physics Research B, 33, p.701 - 705, 1988/00
no abstracts in English
Saido, Masahiro; H.L.Bay*; H.Gnaser*; W.O.Hofer*; J.Bohdansky*; J.Roth*
Journal of Nuclear Materials, 145-147, p.387 - 390, 1987/00
Times Cited Count:1 Percentile:19.22(Materials Science, Multidisciplinary)no abstracts in English
; H.Gnaser*; W.O.Hofer*
Nuclear Instruments and Methods in Physics Research B, 28, p.540 - 547, 1987/00
Times Cited Count:11 Percentile:76.59(Instruments & Instrumentation)no abstracts in English
; H.Gnaser*; W.O.Hofer*
Applied Physics A, 40, p.197 - 202, 1986/00
Times Cited Count:22 Percentile:72.55(Materials Science, Multidisciplinary)no abstracts in English
; ;
Metall.Trans.,A, 17, p.2031 - 2034, 1986/00
no abstracts in English
; H.L.Bay*; J.Bohdansky*; J.Roth*
Nuclear Instruments and Methods in Physics Research B, 13, p.403 - 407, 1986/00
Times Cited Count:12 Percentile:79.61(Instruments & Instrumentation)no abstracts in English
Motoki, Ryozo; ; ; Motoishi, Shoji; ; ; ;
JAERI-M 84-015, 34 Pages, 1984/02
no abstracts in English
Journal of Nuclear Materials, 128-129, p.540 - 544, 1984/00
Times Cited Count:18 Percentile:83.93(Materials Science, Multidisciplinary)no abstracts in English