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Journal Articles

Development of a radiation tolerant laser-induced breakdown spectroscopy system using a single crystal micro-chip laser for remote elemental analysis

Tamura, Koji; Nakanishi, Ryuzo; Oba, Hironori; Karino, Takahiro; Shibata, Takuya; Taira, Takunori*; Wakaida, Ikuo

Journal of Nuclear Science and Technology, 61(8), p.1109 - 1116, 2024/08

https://doi.org/10.1080/00223131.2023.2298485
 Times Cited Count：1 Percentile：31.89(Nuclear Science & Technology)

Journal Articles

Summary report in FY2022 of subsidy program for "the Project of Decommissioning and Contaminated Water Management (Development of Analysis and Estimation Technology for Characterization of Fuel Debris (Development of Technologies for Enhanced Analysis Accuracy, Thermal behavior Estimation, and Simplified Analysis of Fuel Debris)" started in FY2011

Koyama, Shinichi; Ikeuchi, Hirotomo; Mitsugi, Takeshi; Maeda, Koji; Sasaki, Shinji; Onishi, Takashi; Tsai, T.-H.; Takano, Masahide; Fukaya, Hiroyuki; Nakamura, Satoshi; et al.

Hairo, Osensui, Shorisui Taisaku Jigyo Jimukyoku Homu Peji (Internet), 216 Pages, 2023/11

https://en.dccc-program.jp/wp-content/uploads/20231117_JAEA.pdf

In FY 2021 and 2022, JAEA perfomed the subsidy program for "the Project of Decommissioning and Contaminated Water Management (Development of Analysis and Estimation Technology for Characterization of Fuel Debris (Development of Technologies for Enhanced Analysis Accuracy, Thermal Bahavior Estimation, and Simplified Analysis of Fuel Debris)" started in FY 2021. This presentation material summarized the results of the project, which will be available shortly on the website of Management Office for the Project of Decommissioning, Contaminated Water and Treated Water Management.

Journal Articles

Dispersive XAFS Study on the Laser-Induced Reduction of a Rh$$^{3+}$$ ion complex; Presence of a Rh$$^{+}$$ Intermediate in Direct Photoreduction

Saeki, Morihisa*; Matsumura, Daiju; Nakanishi, Ryuzo*; Yomogida, Takumi; Tsuji, Takuya; Saito, Hiroyuki*; Oba, Hironori*

Journal of Physical Chemistry C, 126(12), p.5607 - 5616, 2022/03

https://doi.org/10.1021/acs.jpcc.1c10160
 Times Cited Count：2 Percentile：14.72(Chemistry, Physical)

The reaction mechanism of the direct photoreduction of a Rh$$^{3+}$$ ion complex to a Rh$$^{0}$$ species induced by pulsed ultraviolet laser irradiation was studied using dispersive X-ray absorption fine structure (DXAFS) spectroscopy. The time-resolved X-ray absorption near edge structure (XANES) showed the absence of isosbestic points and suggested that more than two Rh$$^{n+}$$ species contribute toward the direct photoreduction of Rh$$^{3+}$$. Analysis of the time-resolved XANES data by singular value deposition showed that the direct photoreduction involves three Rh$$^{n+}$$ species. Multivariate curve resolution by alternating least-squares analysis (MCR-ALS) of the time-resolved XANES data gave pure spectra and concentration profiles of the three Rh$$^{n+}$$ species. The Rh$$^{n+}$$ species were assigned to Rh$$^{3+}$$, Rh$$^{+}$$, and Rh$$^{0}$$ species based on the features of the pure XANES spectra. The concentration profiles suggested that the direct photoreduction proceeds in the order of Rh$$^{3+}$$ $$rightarrow$$ Rh$$^{+}$$ $$rightarrow$$ Rh$$^{0}$$. A reaction mechanism, which was proposed involving photoreductions of Rh$$^{3+}$$ and Rh$$^{+}$$, photoinduced autocatalytic reductions of Rh$$^{3+}$$ and Rh$$^{+}$$, and photooxidation of Rh$$^{+}$$, well reproduced the concentration profiles of three Rh$$^{n+}$$ species.

Journal Articles

Highly sensitive detection of sodium in aqueous solutions using laser-induced breakdown spectroscopy with liquid sheet jets

Nakanishi, Ryuzo; Oba, Hironori; Saeki, Morihisa; Wakaida, Ikuo; Tanabe, Rie*; Ito, Yoshiro*

Optics Express (Internet), 29(4), p.5205 - 5212, 2021/02

https://doi.org/10.1364/OE.415308
 Times Cited Count：21 Percentile：85.60(Optics)

Laser-induced breakdown spectroscopy (LIBS) combined with liquid jets was applied to the detection of trace sodium (Na) in aqueous solutions. The sensitivities of two types of liquid jets were compared: a liquid cylindrical jet with a diameter of 500 $$mu$$m and a liquid sheet jet with a thickness of 20 $$mu$$m. Compared with the cylindrical jet, the liquid sheet jet effectively reduced the splash from the laser-irradiated surface and produced long-lived luminous plasma. The limit of detection (LOD) of Na was determined to be 0.57 $$mu$$g/L for the sheet jet and 10.5 $$mu$$g/L for the cylindrical jet. The LOD obtained for the sheet jet was comparable to those obtained for commercially available inductively coupled plasma emission spectrometers.

Journal Articles

Application of an augmentation method to MCR-ALS analysis for XAFS and Raman data matrices in the structural change of isopolymolybdates

Saeki, Morihisa*; Yomogida, Takumi; Matsumura, Daiju; Saito, Takumi*; Nakanishi, Ryuzo*; Tsuji, Takuya; Oba, Hironori*

Analytical Sciences, 36(11), p.1371 - 1378, 2020/11

https://doi.org/10.2116/analsci.20P147
 Times Cited Count：4 Percentile：17.28(Chemistry, Analytical)

We measured X-ray absorption fine structure (XAFS) and Raman spectra of isopolymolybdates(VI) in HNO$$_{3}$$ solution (0.15- 4.0 M), which change their geometries depending on acid concentration, and performed simultaneous resolution of the XAFS and Raman data using a multivariate curve resolution by alternating least-squares (MCR-ALS) analysis. In iterative ALS optimization, initial data matrices were prepared by two different methods. The MCR-ALS result of single XAFS data matrix shows large dependence on the preparation method of the initial data matrices. The MCR-ALS result of an augmented matrix of Raman and XAFS data has little dependence on the initial data matrices. It indicates that the augmentation method effectively improves the rotation ambiguities in the MCR-ALS analysis of the XAFS data. Based on the model fitting of the pure EXAFS oscillations, we revealed the change of [Mo$$_{36}$$O$$_{112}$$(H$$_{2}$$O)$$_{16}$$]$$^{2+}$$ $$rightarrow $$ [Mo$$_{2}$$O$$_{5}$$(H$$_{2}$$O)$$_{6}$$]$$^{2+}$$ $$rightarrow $$ [HMoO$$_{3}$$(H$$_{2}$$O)$$_{3}$$]$$^{+}$$ in the highly concentrated HNO$$_{3}$$ solution.

Oral presentation

In situ time-resolved XAFS studies on photo-induced particle formation in an aqueous/ethanol solution of PdCl$$_{4}$$$$^{2-}$$ using ns pulsed UV laser; Dependence of chemical kinetics on laser pulse energy

Saeki, Morihisa*; Yomogida, Takumi; Matsumura, Daiju; Nakanishi, Ryuzo*; Taguchi, Tomitsugu*; Tsuji, Takuya; Saito, Hiroyuki*; Oba, Hironori*

no journal, , 

In the absence of a photoactivator, the laser-induced particle formation in an H$$_{2}$$O/ EtOH solution of PdCl$$_{4}$$$$^{2-}$$ was performed by three kinds of irradiation condition using fourth harmonics of the pulsed UV laser (266 nm). In the irradiation, pulsed laser energy was arranged to 5, 10 and 25 mJ, where average laser power is kept to 250 mW. The reaction kinetics of the laser-induced particle formation was observed using dispersive XAFS measurement. About half of Pd ions were reduced with 5 mJ pulsed laser irradiation. In contrast, all Pd ions were reduced with 25 mJ pulsed laser irradiation. The result elucidates that the laser photon contributes to the generation of Pd metals by the multi-photon process.

Oral presentation

Development on laser remote analysis for on-site, in-situ and quick screening of nuclear fuel debris in decommissioning of Fukushima Daiichi Nuclear Power Station

Wakaida, Ikuo; Oba, Hironori; Miyabe, Masabumi; Akaoka, Katsuaki; Oba, Masaki; Tamura, Koji; Saeki, Morihisa; Nakanishi, Ryuzo; Ikeda, Yuji*; Sakka, Tetsuo*; et al.

no journal, , 

Oral presentation

Laser remote analysis for decommissioning of Fukushima Daiichi Nuclear Power Station

Wakaida, Ikuo; Oba, Hironori; Akaoka, Katsuaki; Shibata, Takuya; Nakanishi, Ryuzo; Karino, Takahiro

no journal, , 

no abstracts in English

Oral presentation

Laser remote analysis for decommissioning of Fukushima Daiichi Nuclear Power Station (1FNPS) and its application in the actual site

Wakaida, Ikuo; Oba, Hironori; Nakanishi, Ryuzo; Akaoka, Katsuaki; Shibata, Takuya

no journal, , 

Oral presentation

Dispersive XAFS study on the laser-induced reduction of a Rh$$^{3+}$$ ion complex in a H$$_{2}$$O/EtOH solution

Saeki, Morihisa*; Matsumura, Daiju; Nakanishi, Ryuzo*; Yomogida, Takumi; Tsuji, Takuya; Saito, Hiroyuki*; Oba, Hironori*

no journal, , 

The reaction mechanism of the direct photo-reduction of a Rh$$^{3+}$$ ion complex to a Rh$$^{0}$$ species was studied using dispersive X-ray absorption fine structure spectroscopy. The time-resolved X-ray absorption near edge structure (XANES) showed the absence of isosbestic points. It suggested that more than two Rhn+ species contribute toward the reaction. We applied singular value deposition to the time-resolved XANES data and showed the contribution of three Rh$$^{n+}$$ species to the direct photoreduction. Next, in order to extract spectral information on the Rh$$^{n+}$$ intermediate, we analyzed the time-resolved XANES data using multivariate curve resolution analysis, which gives pure spectra and concentration profile of the Rh$$^{n+}$$ species. Finally, based on feature of the pure spectrum, we assigned the Rh$$^{n+}$$ intermediate to the Rh$$^{n+}$$ species.

Oral presentation

Laser remote analysis by optical fiber coupled laser induced breakdown spectroscopy for on-site, in-situ screening of nuclear debris in decommissioning of Fukushima Daiichi Nuclear Power Station

Wakaida, Ikuo; Oba, Hironori; Akaoka, Katsuaki; Nakanishi, Ryuzo; Shibata, Takuya; Karino, Takahiro

no journal, , 

Oral presentation

Research and development of laser remote analysis for decommissioning of Fukushima Daiichi Nuclear Power Station

Wakaida, Ikuo; Oba, Hironori; Akaoka, Katsuaki; Shibata, Takuya; Nakanishi, Ryuzo; Karino, Takahiro; Sakamoto, Kan*; Ikeda, Yuji*; Taira, Takunori*

no journal, , 

no abstracts in English

Oral presentation

Practical application of LIBS and rerated spectroscopy for decommissioning work of Fukushima Daiichi Nuclear Power Station

Wakaida, Ikuo; Oba, Hironori; Miyabe, Masabumi; Akaoka, Katsuaki; Oba, Masaki; Tamura, Koji; Saeki, Morihisa; Nakanishi, Ryuzo; Ikeda, Yuji*; Sakka, Tetsuo*; et al.

no journal, , 

no abstracts in English

Oral presentation

Gamma-ray irradiation effects to the laser-induced breakdown spectroscopy system using a ceramic and a single crystal micro-laser

Tamura, Koji; Nakanishi, Ryuzo; Oba, Hironori; Saeki, Morihisa; Taguchi, Tomitsugu*; Lim, H. H.*; Taira, Takunori*; Wakaida, Ikuo

no journal, , 

Oral presentation

Rare earth elements detection in mixed oxide using a fiber optic LIBS with a ceramic micro-laser

Oba, Hironori; Tamura, Koji; Nakanishi, Ryuzo; Saeki, Morihisa; Lim, H. H.*; Taira, Takunori*; Wakaida, Ikuo

no journal, , 

Oral presentation

DXAFS study on laser-induced photoreduction mechanism of Rh$$^{III}$$ ion complexes; Extraction of intermediates information by multivariate spectral analysis

Saeki, Morihisa*; Matsumura, Daiju; Nakanishi, Ryuzo*; Yomogida, Takumi; Tsuji, Takuya; Saito, Hiroyuki*; Oba, Hironori*

no journal, , 

The precious metal (PM) ions complexed with negative ions and water molecules in solution has a charge transfer absorption band in the UV region. When alcohol is added to such a PM$$^{n+}$$ complex solution and irradiated with an ultraviolet laser, the PM$$^{n+}$$ complex is electronically excited and reacts with the alcohol to be reduced to the neutral atom PM$$^{0}$$. The reduced PM$$^{0}$$ spontaneously aggregates in the solution to form fine particles. This process is called Laser-Induced Particle Formation (LIPF), and is used for the formation of precious metal nanoparticles and the recovery of precious metals from factory effluents. We have investigated the LIPF reaction mechanism of Rh$$^{3+}$$ ion complexes by in situ energy-dispersive X-ray absorption fine structure spectroscopy(XAFS). As a result of analyzing the obtained XAFS spectra, we found that Rh species with three oxidation numbers are involved in the Rh$$^{3+}$$reduction reaction, which proceeds from Rh$$^{3+}$$ to Rh$$^{int}$$ (intermediate) to Rh$$^{0}$$.

Oral presentation

Comparison of radiation effects for a ceramics and a single crystal microchip of a Laser-Induced Breakdown Spectroscopy (LIBS) system for remote analysis

Tamura, Koji; Nakanishi, Ryuzo; Oba, Hironori; Wakaida, Ikuo

no journal, , 

Oral presentation

Sensitive detection of alkali and precious metals in aqueous solutions using LIBS with liquid sheet jets

Nakanishi, Ryuzo; Saeki, Morihisa; Oba, Hironori

no journal, , 

Oral presentation

Challenging and development on radiation hardend laser remote analysis for in-situ screening of nuclear fuel debris in decommissioning of Fukushima Daiichi Nuclear Power Station

Wakaida, Ikuo; Oba, Hironori; Akaoka, Katsuaki; Karino, Takahiro; Nakanishi, Ryuzo*; Sakamoto, Kan*; Ikeda, Yuji*; Taira, Takunori*

no journal, , 

Oral presentation

Development of quick and remote analysis for severe accident reactor, 9-1; Current results and challenges in development of laser in-situ remote analysis for nuclear fuel debris in decommissioning of Fukushima Daiichi Nuclear Power Station-2

Wakaida, Ikuo; Oba, Hironori; Akaoka, Katsuaki; Karino, Takahiro; Sakamoto, Kan*; Nakanishi, Ryuzo*; Kashiwakura, Shunsuke*; Taira, Takunori*; Ikeda, Yuji*; Deguchi, Yoshihiro*

no journal, , 

We are developing remote in-situ analysis by laser induced breakdown spectroscopy (LIBS) for simple in-situ screening analysis of fuel debris in the decommissioning of the Fukushima Daiichi Nuclear Power Station. For various application scenarios, microchip laser based LIBS for ultra-long distance analysis, microwave assisted LIBS for signal enhancement, and long/short double pulse laser LIBS for water-containing samples are developing as the fiber-optic LIBS system. To have the reliability, valuation with nuclear fuel materials and spent fuel, and radiation resistance test by $$^{60}$$Co irradiation will be planed. As a challenging trial, a development of Machine learning technique has introduced for automatically analysis of LIBS spectra.

33 (Records 1-20 displayed on this page)