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Saito, Shigeru; Suzuki, Kazuhiro; Obata, Hiroki; Dai, Y.*
Nuclear Materials and Energy (Internet), 34, p.101338_1 - 101338_9, 2023/03
Times Cited Count：2 Percentile：53.91(Nuclear Science & Technology)In this study, a post-irradiation examination of pure tungsten (W) and tantalum (Ta) specimens irradiated at the Swiss Spallation-Neutron Source is conducted. W is used as a potential candidate for a solid spallation-target material owing to its favorable properties. However, W also suffers from several disadvantages such as poor corrosion resistance to water coolant and irradiation embrittlement. To improve these properties, cladding technologies using Ta for W alloys have been developed. In the present study, we investigated the irradiation effects on two tungsten materials, poly-crystal W (W-Poly) and single-crystal W (W-Sin), along with pure polycrystalline Ta. The tensile-test results revealed that W-Poly exhibited almost no ductility after irradiation of 10.2-35.0 dpa. W-Sin was irradiated up to 10.2 dpa and demonstrated 6% of total elongation (TE). With regard to Ta, TE decreased based on the increase in irradiation, reaching almost zero at doses of more than 10.3 dpa.
Ishijima, Yasuhiro; Ueno, Fumiyoshi; Abe, Hitoshi
Materials Transactions, 63(4), p.538 - 544, 2022/04
Times Cited Count：0 Percentile：0(Materials Science, Multidisciplinary)The time dependence of the corrosion behavior of tantalum (Ta), which is used in nuclear fuel reprocessing equipment, in sodium hydroxide (NaOH) solutions was investigated by immersion tests, and the mechanism of the time dependence was examined via surface observations and electrochemical measurements. The immersion tests were conducted at room temperature with NaOH concentrations ranging from 1 to 7 mol/L for immersion periods of 24 to 168 h. The corrosion rate increased with the NaOH concentration but peaked with the immersion period and then decreased. The time to peak of the corrosion rate was shorter with higher NaOH concentration. The X-ray diffraction (XRD) patterns and Raman spectra of the surfaces of the specimens immersed in the 7 mol/L NaOH solution for more than 48 h showed Na
Ta
O
formation. The polarization resistance decreased with immersion time for all NaOH concentrations up to about 24 h after immersion. Thereafter, the polarization resistance increased with immersion time in 7 mol/L NaOH solution and remained almost constant in the other NaOH concentrations. Findings suggested that the change in the corrosion rate was affected by the film formation during immersion, since the time dependence of the polarization resistance and the sum of film resistance and charge transfer resistance had the same tendencies. The precipitation film was mainly NaTaO formed by the dissolution of the passivity film on Ta.
Ishijima, Yasuhiro; Ueno, Fumiyoshi; Abe, Hitoshi
Zairyo To Kankyo, 70(6), p.192 - 198, 2021/06
The time dependence of corrosion behavior on tantalum used in nuclear fuel reprocessing equipment in sodium hydroxide solution was investigated by immersion corrosion tests, and the mechanism of aging change was discussed from surface observations and electrochemical measurements. The immersion tests were carried out at room temperature with NaOH concentrations ranging from 1 to 7 mol/L and immersion times ranging from 24 to 168 hr, respectively. The corrosion rate increased with NaOH concentration, but peaked with immersion time and then decreased. The time to peak of corrosion rate was shorter with higher NaOH concentration. The SEM observations and Raman analysis at the surface of the specimens that were cleaned and weighed after the immersion test did not show any film formation. On the other hand, the polarization resistance showed a constant value or an increase after a decrease immediately after immersion. It is suggested that the change in corrosion rate is affected by the formation of film by immersion, since the value of polarization resistance is almost the same as the sum of film resistance and charge transfer resistance. The film was considered to be mainly NaTaO formed by the dissolution of Ta.
Shibata, Keiichi
Journal of Nuclear Science and Technology, 53(7), p.957 - 967, 2016/07
Times Cited Count：5 Percentile：43.41(Nuclear Science & Technology)Neutron nuclear data on 
Ta have been evaluated for the next version of Japanese Evaluated Nuclear Data Library general-purpose file in the energy region from 
eV to 20 MeV. Resolved resonance parameters were selected from experimental data, while unresolved ones were obtained from nuclear model calculations. A statistical model code CCONE was applied to evaluate cross sections above the resolved resonance region. Compound, pre-equilibrium and direct-reaction processes were considered for cross-section calculation. Coupled-channel optical model parameters were employed for the interaction between neutrons and nuclei. Giant-dipole and pygmy resonance parameters for E1 
-ray transition from tantalum isotopes were determined so as to reproduce measured -ray spectrum. The present results reproduce experimental data very well, and are much better than the JENDL-4.0 evaluation. The evaluated data are compiled into ENDF-formatted data files.
Nb and 
Ta for chemical studies of element 105, Db, using the GARIS gas-jet systemHuang, M.*; Haba, Hiromitsu*; Murakami, Masashi*; Asai, Masato; Kaji, Daiya*; Kanaya, Jumpei*; Kasamatsu, Yoshitaka*; Kikunaga, Hidetoshi*; Kikutani, Yuki*; Komori, Yukiko*; et al.
Journal of Radioanalytical and Nuclear Chemistry, 304(2), p.845 - 849, 2015/05
Times Cited Count：3 Percentile：25.85(Chemistry, Analytical)A technique to utilize radioisotopes of Nb and Ta was developed for chemical studies of element 105, Db, by coupling a gas-jet transport system to the RIKEN gas-filled recoil ion separator (GARIS). The short-lived Nb and Ta were produced with nuclear reactions using a 
F beam whose energy was the same as that to produce 
Db. Then, they were separated with GARIS and extracted to a chemistry laboratory with the gas-jet transport system. By changing only magnetic field of GARIS and inserting an energy degrader and a shutter for recoil ions, we could deliver the Nb and Ta to a chemistry device for Db without changing other experimental conditions.
cycling techniques for thermo chemical hydrogen production process; R&D on refractory and corrosion resistant pressure sensor for hydrogen iodide cycling test loopIshiyama, Shintaro
Nihon Kikai Gakkai Rombunshu, A, 69(686), p.102 - 107, 2003/10
no abstracts in English
Ishiyama, Shintaro
Materia, 42(1), p.58 - 60, 2003/01
no abstracts in English
Kawai, Masayoshi*; Kikuchi, Kenji; Kurishita, Hiroaki*; Li, J.*; Furusaka, Michihiro*
Journal of Nuclear Materials, 296(1-3), p.312 - 320, 2001/07
Times Cited Count：47 Percentile：93.85(Materials Science, Multidisciplinary)no abstracts in English
Shiotsu, Masahiro*; Hata, Koichi*; *; Shirai, Yasuyuki*; *; Sakai, Takaaki
PNC TY9604 97-002, 15 Pages, 1997/03
no abstracts in English
; R.M.Lambrecht*; Matsuoka, Hiromitsu; Osa, Akihiko; Koizumi, Mitsuo; Kobayashi, Katsutoshi; Izumo, Mishiroku; Hashimoto, Kazuyuki; Sekine, Toshiaki
Applied Radiation and Isotopes, 47(2), p.171 - 174, 1996/00
Times Cited Count：4 Percentile：39.42(Chemistry, Inorganic & Nuclear)no abstracts in English
; Nishino, Yasuharu; Yamahara, Takeshi;
Proc. of 43rd Conf. on Robotics and Remote Systems 1995, 0, p.75 - 80, 1996/00
no abstracts in English
; Nishino, Yasuharu; Yamahara, Takeshi;
Transactions of the American Nuclear Society, 73, p.465 - 466, 1995/00
no abstracts in English
; Nishino, Yasuharu;
JAERI-M 93-244, 93 Pages, 1994/01
no abstracts in English
Sasaki, Yuji; Takeishi, Hideyo; Adachi, Takeo; *
Journal of Radioanalytical and Nuclear Chemistry, 139(1), p.143 - 151, 1990/00
Times Cited Count：5 Percentile：52.84(Chemistry, Analytical)no abstracts in English
; ; ; *
Journal of Nuclear Science and Technology, 24(6), p.480 - 489, 1987/06
Times Cited Count：2 Percentile：29.78(Nuclear Science & Technology)no abstracts in English
*; ;
JAERI-M 87-026, 25 Pages, 1987/02
no abstracts in English
*; ; *
Journal of Nuclear Science and Technology, 20(8), p.707 - 709, 1983/00
Times Cited Count：1 Percentile：27.09(Nuclear Science & Technology)no abstracts in English
;
JAERI-M 7582, 32 Pages, 1978/03
no abstracts in English
;
Bunseki Kagaku, 24(5), p.303 - 307, 1975/05
no abstracts in English
