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JAEA Reports

Measurement of high-energy neutron fluxes and spectra around the J-PARC mercury spallation neutron target using multi-foil activation method

Kasugai, Yoshimi; Harada, Masahide; Kai, Tetsuya; Oi, Motoki; Meigo, Shinichiro; Maekawa, Fujio

JAEA-Data/Code 2015-033, 28 Pages, 2016/03

JAEA-Data-Code-2015-033.pdf:1.78MB

The high-energy neutron fluxes and spectra around the mercury spallation neutron source at MLF of J-PARC were measured by the multi-foil activation method. The threshold energies of neutron reactions utilized in this experiment covered from 0.1 to 50 MeV. The foil irradiation was carried out on the first beam-run of MLF from May 30th to 31th, 2008. After the irradiation, the induced radioactivity of each foil was measured using an HPGe detector, and the neutron-induced reaction-rate distribution around the mercury target was determined. Using these data, the high-energy neutron fluxes and spectra were deduced with unfolding method in which the neutron spectra calculated with PHITS code were used as the initial-guess spectra. By comparison between the initial and the unfolded spectra, it was shown that most of the calculation results, which had been the basis of the neutronics design of the MLF target assembly, were consistent with the experimental data within $$pm$$30%.

Journal Articles

Diffusion of tritium in intermetallic compound $$beta$$-LiAl; Relation to the defect structure

Sugai, Hiroyuki

Solid State Ionics, 177(39-40), p.3507 - 3512, 2007/01

The diffusion coefficient and its activation energy (116.3 $$pm$$ 11.7 kJ/mol) of tritium in an intermetallic compound $$beta$$-LiAl are determined at temperatures from 700 to 848 K. Though the present result for the diffusion coefficient is almost the same as that reported previously, the present result for the activation energy turns out nearly twice of that (64.9 $$pm$$ 3.8 kJ/mol). The present result for the activation energy is consistent with the systematics that an increase of lithium concentration in Al-Li systems increases the activation energy, but the previous result is not. Furthermore, a consideration of the crystal structure and defect structure suggests that tritium diffuses and is impeded by the attractive interaction with lithium atom at lithium sublattices.

Journal Articles

Diffusion of tritium in intermetallic compound $$beta$$-LiAl; Relation to the defect structure

Sugai, Hiroyuki

Solid State Ionics, 177(39-40), p.3507 - 3512, 2007/01

 Times Cited Count:3 Percentile:80.7(Chemistry, Physical)

The diffusion coefficients and its activation energy (103.7$$pm$$9.5 kJ/mol) for tritium in intermetallic compound $$beta$$-LiAl are determined at temperatures from 699 to 886 K. Though the present result for the diffusion coefficient is almost the same as that reported earlier, the activation energy turns out nearly twice of that (64.9$$pm$$3.8 kJ/mol) reported earlier. On the basis of the crystal structure and defect structure, the large activation energy of this study suggest that tritium diffuses interstitially and is impeded by an attractive interaction with lithium atoms in lithium sublattices.

Journal Articles

Nuclear technology and potential ripple effect of superconducting magnets for fusion power plant

Nishimura, Arata*; Muroga, Takeo*; Takeuchi, Takao*; Nishitani, Takeo; Morioka, Atsuhiko

Fusion Engineering and Design, 81(8-14), p.1675 - 1681, 2006/02

 Times Cited Count:3 Percentile:73.68(Nuclear Science & Technology)

In a fusion reactor plant, a neutral beam injector (NBI) will be operated for a long time, and it will allow neutron streaming from NBI ports to outside of the plasma vacuum vessel. It requires the superconducting magnet to develop nuclear technology to produce stable magnetic field and to reduce activation of the magnet components. In this report, the back ground of the necessity and the contents of the nuclear technology of the superconducting magnets for fusion application are discussed and some typical investigation results are presented, which are the neutron irradiation effect on Nb$$_{3}$$Sn wire, the development of low activation superconducting wire, and the design concept to reduce nuclear heating and nuclear transformation by streaming. In addition, recent activities in high energy particle physics are introduced and potential ripple effect of the technology of the superconducting magnets is described briefly.

Journal Articles

Effects of neutron irradiation on some superplastic characteristics of tetragonal zirconia polycrystals containing 3 mol% yttria

Shibata, Taiju; Ishihara, Masahiro; Motohashi, Yoshinobu*; Ito, Tsutomu*; Baba, Shinichi; Kikuchi, Makoto*

Materials Transactions, 45(8), p.2580 - 2583, 2004/08

 Times Cited Count:3 Percentile:71.54(Materials Science, Multidisciplinary)

Fast neutrons (energy $$>$$ 1.6$$times$$10$$^{23}$$ J) were irradiated to tetragonal zirconia polycrystals containing 3 mol% yttria (3Y-TZP) at the fluence levels of 2.5$$times$$10$$^{24}$$ (Light irradiation) and 4.3$$times$$10$$^{24}$$ (Heavy irradiation) m$$^{-2}$$. The irradiation caused no significant swelling in the 3Y-TZP specimens. After the neutron irradiation, superplastic characteristics were examined by tensile tests at a temperature range from 1623 to 1773 K with initial strain rates ranging from 5.0$$times$$10$$^{-4}$$ to 1.67$$times$$10$$^{-2}$$s$$^{-1}$$. It was found that the elongation to fracture of the irradiated specimens was quite small in comparison with the unirradiated ones. The apparent activation energy for the superplastic flow of the irradiated 3Y-TZP was fairly high, i.e., 781 and 693 kJ・mol$$^{-1}$$ for Light and Heavy irradiations, respectively. Atomic displacement damages and defects in the 3Y-TZP caused by the irradiation were thought to be main causes of these property changes.

JAEA Reports

Catalytic activity of catalysts for steam reforming reaction (Contract research)

Ohashi, Hirofumi; Inagaki, Yoshiyuki

JAERI-Tech 2003-046, 47 Pages, 2003/05

JAERI-Tech-2003-046.pdf:3.15MB

no abstracts in English

Journal Articles

Superplastic deformation characteristics of 3Y-TZP after Zr ion irradiation

Shibata, Taiju; Ishihara, Masahiro; Motohashi, Yoshinobu*; Baba, Shinichi; Hoshiya, Taiji; Kobayashi, Tomokazu*; Harjo, S.*; Sakuma, Takaaki*

Nuclear Instruments and Methods in Physics Research B, 206, p.139 - 143, 2003/05

 Times Cited Count:4 Percentile:65.26(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Ion irradiation effect on superplastic deformation behavior of ceramic material

Shibata, Taiju; Ishihara, Masahiro; Motohashi, Yoshinobu*; Baba, Shinichi; Hoshiya, Taiji; Sakuma, Takaaki*

Nippon Kikai Gakkai Kanto Shibu Ibaraki Koenkai (2002) Koen Rombunshu (No.020-3), p.123 - 124, 2002/09

Applications of superplastic ceramics to nuclear energy fields are very promising because of their superior mechanical and thermal properties. In this study, Zr ion irradiation effects on superplastic deformation behavior of a typical superplastic ceramic, 3mol% yttria containing tetragonal zirconia polycrystals (3Y-TZP), were studied. Zr$$^{+11}$$ ions with 130MeV were irradiated on the 3Y-TZP specimens by TANDEM accelerator at fluence levels of 3.5x10$$^{16}$$ and 2.1x10$$^{17}$$ions/m$$^{2}$$. Their mechanical properties were examined by three-point bending test at elevated temperatures after the irradiation. As a result, at the temperature range from the room temperature to 1473K, any obvious irradiation effects were not found by the bending test. On the other hand, at the range from 1623K to 1773K, it was found that the superplastic deformation behavior was changed by the Zr ion irradiation. The activation energy of superplastic deformation was increased with increasing the irradiation fluence.

Journal Articles

Neutronics experiments for ITER at JAERI/FNS

Konno, Chikara; Maekawa, Fujio; Kasugai, Yoshimi; Uno, Yoshitomo; Kaneko, Junichi; Nishitani, Takeo; Wada, Masayuki*; Ikeda, Yujiro; Takeuchi, Hiroshi

Nuclear Fusion, 41(3), p.333 - 337, 2001/03

 Times Cited Count:3 Percentile:88.32(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Apparent diffusion coefficients and chemical species of neptunium(V) in compacted na-montmorillonite

Kozai, Naofumi; Inada, Koichi*; Kozaki, Tamotsu*; Sato, Seichi*; Ohashi, Hiroshi*; Bamba, Tsunetaka

Journal of Contaminant Hydrology, 47(2-4), p.149 - 158, 2001/02

 Times Cited Count:15 Percentile:55.01(Environmental Sciences)

no abstracts in English

JAEA Reports

An Investigation of neutron irradiation test on superplastic zirconia-ceramic materials

Shibata, Taiju; Motohashi, Yoshinobu*; Ishihara, Masahiro; Baba, Shinichi; Hayashi, Kimio

JAERI-Review 2000-008, p.31 - 0, 2000/05

JAERI-Review-2000-008.pdf:1.64MB

no abstracts in English

Journal Articles

Measurement of induced radioactivity in copper exposed to high energy heavy ion beam

Kim, E.; Nakamura, Takashi*; Uwamino, Y.*; Ito, S.*; Fukumura, A.*

Journal of Nuclear Science and Technology, 37(Suppl.1), p.811 - 815, 2000/03

no abstracts in English

JAEA Reports

IRACM: A Code system to calculate induced radioactivity produced by ions and neutrons

; Fukuda, Mitsuhiro; ; Watanabe, Hiromasa; Yamano, Naoki*

JAERI-Data/Code 97-019, 91 Pages, 1997/05

JAERI-Data-Code-97-019.pdf:2.58MB

no abstracts in English

Journal Articles

Dissolution of ThO$$_{2}$$-based oxides in nitric acid solutions at elevated temperatures

Akabori, Mitsuo; Shiratori, Tetsuo

Journal of Nuclear Science and Technology, 31(6), p.539 - 545, 1994/06

 Times Cited Count:14 Percentile:23.54(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Ion irradiation effects in EuBa$$_{2}$$Cu$$_{3}$$O$$_{y}$$ thin film

; Iwase, Akihiro; Iwata, Tadao; Maeta, Hiroshi; *; *

J. Supercond., 7(1), p.241 - 242, 1994/00

no abstracts in English

Journal Articles

Critical current and activation energy in Bi$$_{2}$$Sr$$_{2}$$Ca$$_{1}$$Cu$$_{2}$$O$$_{x}$$ films after ion irradiation

Hoshiya, Taiji; Takamura, Saburo; ; *; *; *; *

Japanese Journal of Applied Physics, 29(11), p.L2026 - L2029, 1990/11

 Times Cited Count:5 Percentile:64.97(Physics, Applied)

no abstracts in English

Journal Articles

Nuclear spin relaxation in molten LiBeF$$_{3}$$

Ono, Hideo; *

Journal of Nuclear Science and Technology, 27(1), p.45 - 48, 1990/01

no abstracts in English

Journal Articles

Diffusion coefficients of cesium in un-irradiated graphite and comparison with those obtained from in-pile experiments

; Fukuda, Kosaku

Journal of Nuclear Materials, 168, p.328 - 336, 1989/00

 Times Cited Count:9 Percentile:29.04(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

XPS and TDS studies of trapping states of helium implanted in TiO$$_{2}$$

;

Journal of Nuclear Materials, 152, p.295 - 300, 1988/00

 Times Cited Count:3 Percentile:59.13(Materials Science, Multidisciplinary)

no abstracts in English

JAEA Reports

26 (Records 1-20 displayed on this page)