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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：3 Percentile：39.40(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 FY2021

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 Behavior Estimation, and Abbreviated Analysis))" 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

Radiation robustness of laser ceramics and single crystal for microchip laser remote analysis

Tamura, Koji; Nakanishi, Ryuzo; Oba, Hironori; Taira, Takunori*; Wakaida, Ikuo

Japanese Journal of Applied Physics, 61(3), p.032003_1 - 032003_5, 2022/03

https://doi.org/10.35848/1347-4065/ac4dd1
 Times Cited Count：2 Percentile：10.14(Physics, Applied)

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：3 Percentile：12.89(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：33 Percentile：88.76(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

Detection of gadolinium in surrogate nuclear fuel debris using fiber-optic laser-induced breakdown spectroscopy under gamma irradiation

Nakanishi, Ryuzo; Saeki, Morihisa; Wakaida, Ikuo; Oba, Hironori

Applied Sciences (Internet), 10(24), p.8985_1 - 8985_8, 2020/12

https://doi.org/10.3390/app10248985
 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$$_{2}$$O$$_{3}$$, 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.

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：6 Percentile：20.78(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

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

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

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

Fiber-coupled LIBS analysis using a microchip laser in a harsh environment

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

no journal, , 

Development of remote inspection and elemental analysis methods in a harsh radiation environment is required, such as inspection of the nuclear fuel debris at the bottom of the post-accident nuclear reactor (Tokyo Electric Power Company, Fukushima Daiichi Nuclear Power Plant). Laser-induced breakdown spectroscopy (LIBS) has been utilized as an effective qualitative and quantitative analytical method for elemental analysis. Inspecting the damaged reactor vessels requires a longer fiber-optic (FO) cable, which significantly attenuates the delivered laser energy by absorption and scattering in the fiber. We report on the first trial of our FO-LIBS system using the microchip laser (MCL) to identify and quantify elements in surrogate nuclear fuel debris under gamma irradiation, the results of trials on surrogate debris analysis, containing uranium oxide, using the MCL, and the results of 100 m-long fiber-delivered LIBS.

Oral presentation

Challenge of in-situ, on-site laser remote analysis for decommissioning of "Fukushima Daiichi Nuclear PowerStation"

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

no journal, , 

no abstracts in English

Oral presentation

Development of quick and remote analysis for severe accident reactor, 8-1; Current results and challenges in development of laser in-situ remote analysis for nuclear fuel debris in decommissioning of Fukushima Daiichi Nuclear Power Station

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

no journal, , 

no abstracts in English

Oral presentation

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

Detection of trace metals in aqueous solutions by LIBS with liquid sheet jets

Nakanishi, Ryuzo*; Saeki, Morihisa*; Oba, Hironori

no journal, , 

Oral presentation

In Situ Time-Resolved XAFS Studies on Laser-Induced Particle Formation of Platinum Groups Metal Ions in a H$$_{2}$$O / EtOH Solution

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

no journal, , 

When nanosecond pulsed UV laser is irradiated into a H$$_{2}$$O / EtOH solution of platinum group metal (PGM) ions, PGM particles with sub-micron size are formed. We investigated laser induced particle formation of Pd$$^{2+}$$ in the H$$_{2}$$O / EtOH solution by in situ time-resolved XAFS spectroscopy and showed dependence of the reaction rate of laser-induced particle formation on the laser fluence. The dependence on the laser fluence elucidated that the photons contribute not only to the reduction of the Pd$$^{2+}$$, but also to the autocatalytic growth of the Pd particles.

Oral presentation

Metal recovery from liquid wastes by pulsed laser-irradiation

Oba, Hironori; Nakanishi, Ryuzo*; Saeki, Morihisa*

no journal, , 

no abstracts in English

Oral presentation

Laser remote analysis for decommissioning of Fukushima Daiichi Nuclear Power Station (FDNPS) and its application for radioactive sampled materials

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

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.

37 (Records 1-20 displayed on this page)