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Hagiwara, Hiroki; Kosuge, Atsushi; Saito, Junichi; Namie, Masanari; Kisohara, Naoyuki; Minehara, Eisuke*; Tsuboi, Akihiko; Ishimori, Yuu
Next Research (Internet), 8, p.101581_1 - 101581_9, 2026/06
Nakanishi, Ryuzo; Saeki, Morihisa; Wakaida, Ikuo; Oba, Hironori
Applied Sciences (Internet), 10(24), p.8985_1 - 8985_8, 2020/12
Times Cited Count：36 Percentile：88.34(Chemistry, Multidisciplinary)Fiber-optic laser-induced breakdown spectroscopy (FO-LIBS) was applied to a qualitative and quantitative analysis of gadolinium (Gd) in mixed oxide samples, simulating nuclear fuel debris in the damaged reactors of the Fukushima Daiichi Nuclear Power Station. The surrogate debris was prepared from mixed oxide materials containing Gd
O
, with varying Gd concentrations. The emission spectra of the surrogate debris show that the optical emission lines at 501.5 nm and 510.3 nm are suitable for Gd detection in the nuclear fuel debris. LIBS measurements were further performed under gamma irradiation (0-10 kGy/h), resulting in a decrease in spectral intensities due to radiation-induced damage to the optical fiber. For quantification of Gd, robust calibration curves against gamma irradiation were established from the intensity ratio of Gd (501.5 nm)/Ce (474.5 nm) emission lines, yielding the limits of detection for Gd in the range of 0.03-0.08 wt%. These results demonstrate that FO-LIBS is a potential tool for in situ and remote analysis of nuclear fuel debris.
Ito, Chikara; Naito, Hiroyuki; Ishikawa, Takashi; Ito, Keisuke; Wakaida, Ikuo
JPS Conference Proceedings (Internet), 24, p.011038_1 - 011038_6, 2019/01
A high-radiation resistant optical fiber has been developed in order to investigate the interiors of the reactor pressure vessels and the primary containment vessels at the Fukushima Daiichi Nuclear Power Station. The tentative dose rate in the reactor pressure vessels is assumed to be up to 1 kGy/h. We developed a radiation resistant optical fiber consisting of a 1000 ppm hydroxyl doped pure silica core and 4 % fluorine doped pure silica cladding. We attempted to apply the optical fiber to remote imaging technique by means of fiberscope. The number of core image fibers was increased from 2000 to 22000 for practical use. The transmissive rate of infrared images was not affected after irradiation of 1 MGy. No change in the spatial resolution of the view scope by means of image fiber was noted between pre- and post-irradiation. We confirmed the applicability of the probing system, which consists of a view scope using radiation-resistant optical fibers.
Kitazawa, Sin-iti*; Wakai, Eiichi; Aoto, Kazumi
Radiation Physics and Chemistry, 127, p.264 - 268, 2016/10
Times Cited Count：4 Percentile：30.56(Chemistry, Physical)The effects of annealing and double ion irradiation on nuclear structural materials were investigated using a novel, non-destructive, non-contact diagnostic method. A laser-induced and laser-detected surface acoustic wave (SAW) was adopted as a diagnostic system. The SAWs propagation velocity and the SAWs vibration velocity along the normal direction of the surface were measured to investigate mechanical properties of the substrates. Change of the shear modulus was detected in the annealed substrates. Non-linear effect on amplitude of the excited SAW was observed on the double ion irradiated materials. The potential of the SAW diagnostic system for assessing nuclear structural materials was demonstrated.
F
irradiated with two-frequency CO laser lightsYokoyama, Atsushi; Oba, Hironori; Hashimoto, Masashi; Katsumata, Keiichi; Akagi, Hiroshi; Ishii, Takeshi*; Oya, Akio*; Arai, Shigeyoshi*
Applied Physics B, 79(7), p.883 - 889, 2004/11
Times Cited Count：10 Percentile：43.58(Optics)Silicon isotope separation has been done utilizing the Infrared Multiphoton Dissociation of SiF irradiated with two-frequency CO laser lights. The two-frequency excitation method improved the separation efficiency with keeping the high enrichment factors. For example, SiF with the 
Si fraction of 99.4 % was obtained at 40.0 % dissociation of SiF after the simultaneous irradiation of 100 pulses with 966.23 cm
photons (0.089 J/cm
) and 954.55 cm photons (0.92 J/cm), while 1000 pulses were needed to obtain 99.0 % of Si at 27.2 % dissociation in the case of single frequency irradiation at 954.55 cm (0.92 J/cm). The single-step enrichment factors of 
Si and 
Si increased with increasing SiF pressure. The reason for this enhancement has been discussed in terms of the rotational and vibrational relaxations by collisions with ambient gases.
Kitazawa, Shinichi; Putra, P.; Sakai, Seiji; Narumi, Kazumasa; Naramoto, Hiroshi; Yamamoto, Shunya; Chiba, Atsuya
Nuclear Instruments and Methods in Physics Research B, 206, p.952 - 955, 2003/05
Times Cited Count：6 Percentile：42.15(Instruments & Instrumentation)Pulsed energy impacts are expected to generate the elastic waves reflecting the elastic properties of impacted substances. Among the generated waves, the surface acoustic waves (SAW) can be more specific to the surface structures and can be used effectively in the characterization of thin films in a non-destructive way. In the present study, pulsed laser impacts were employed to generate SAWs on a thin film and the SAWs are detected with a laser reflection technique. To test the effectiveness of this method, an amorphous carbon films were irradiated with 13 keV Ar ions at room temperature in a broad range and the SAW propagation velocity was evaluated as a function of Ar ion dose. The present preliminary experiment using pulsed laser suggests the successful detection of SAW from typical substances with different modulus of elasticity such as fcc metals, oxides and semi conducting materials.
Isozaki, Futoshi*; Kikuchi, Taiji; Ioka, Ikuo; Ishikawa, Kazuyoshi; Hirata, Yuji*
JAERI-Tech 2002-074, 22 Pages, 2002/09
JAERI-Tech-2002-074.pdf:4.98MB
The pressurized tube specimens which enclosed high pressure inert gas were produced for the irradiation creep test. The pressurized tube specimen with 7mm outer diameter and 0.5mm wall thickness must be sealed by the welding, after the helium gas was impressed in the inside of tube. In this process, there was a technical problem of welding under high pressure, and it is difficult to seal the pressurized tube specimen in the present facility of our group. The production process was examined by taking shortening in production period and reduction in the cost into consideration. The sealing technology to enclose the helium gas up to 5.5MPa was established by new technique using the present facility and the mock-up test. And, it is necessary to measure the outer diameter of the pressurized tube specimen with high accuracy in order to predict irradiation creep deformation arising from neutron radiation and internal pressure. Therefore, the method for measuring at the 0.01mm measurement accuracy was established, which combined laser measuring instrument with the lathe.
and (U,Gd)OMinato, Kazuo; Shiratori, Tetsuo; Serizawa, Hiroyuki; Hayashi, Kimio; Une, Katsumi*; Nogita, Kazuhiro*; Hirai, Mutsumi*; Amaya, M.*
Journal of Nuclear Materials, 288(1), p.57 - 65, 2001/01
Times Cited Count：25 Percentile：83.05(Materials Science, Multidisciplinary)no abstracts in English
Utsumi, Takayuki*; Sasaki, Akira; Kunugi, Tomoaki*; Fujii, Sadao*; Akamatsu, Mikio*
Proceedings of 13th International Conference on High-Power Particle Beams (BEAMS 2000) (CD-ROM), 4 Pages, 2000/00
no abstracts in English
; Sasaki, Akira; Kunugi, Tomoaki*; ;
Computational Fluid Dynamics Journal, 8(1), p.128 - 134, 1999/04
no abstracts in English
Yamagiwa, Mitsuru; Koga, J. K.; Sagisaka, Akito*; Nagashima, Keisuke
Plasma Physics and Controlled Fusion, 41(2), p.265 - 270, 1999/00
Times Cited Count：2 Percentile：8.70(Physics, Fluids & Plasmas)no abstracts in English
; Kunugi, Tomoaki;
ASME Proc. of 31st National Heat Transfer Conf. (HTD-Vol. 323), 1, p.171 - 178, 1996/00
no abstracts in English
; Kawanishi, Shunichi; Nishii, Masanobu; Sugimoto, Shunichi*;
Japanese Journal of Applied Physics, 33(8), p.4764 - 4768, 1994/08
Times Cited Count：9 Percentile：50.06(Physics, Applied)no abstracts in English
JAERI-M 91-054, 44 Pages, 1991/03
no abstracts in English
Kawanishi, Shunichi; Shimizu, Yuichi; Sugimoto, Shunichi; Suzuki, Nobutake
Polymer, 32(6), p.979 - 983, 1991/00
Times Cited Count：12 Percentile：54.61(Polymer Science)no abstracts in English
