100 m fiber-coupled microchip laser-induced breakdown spectroscopy for remote elemental analysis applications

Batsaikhan, M.; Oba, Hironori; Wakaida, Ikuo

Optics Express (Internet), 32(25), p.45158 - 45170, 2024/12

https://doi.org/10.1364/OE.541447

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

Laser ablation plasma expansion using microwaves

Ikeda, Yuji*; Soriano, J. K.*; Oba, Hironori; Wakaida, Ikuo

Scientific Reports (Internet), 13, p.13901_1 - 13901 _11, 2023/08

https://doi.org/10.1038/s41598-023-41208-z

This study explores the potential of utilizing microwaves to sustain the expansion of transient laser ablation plasma of Zr target. By application of microwaves on the plasma, significant enhancement with a two to three order of magnitude increase in the plasma emission intensity was observed. It was investigated that the electron temperature decreased from 10,000 K to 3000 K with volume expansion owing to increased surrounding air interaction, while the plasma can be sustained in air by using microwaves. These results emphasize the contribution of microwaves in promoting enhanced emission and plasma formation at controlled, low temperature, thereby demonstrating the potential of microwaves to enhance the accuracy and performance of laser-induced breakdown spectroscopy. These also mitigate the generation of toxic fumes and dust during ablation, a critical benefit when handling hazardous materials such as radioactive nuclear fuel debris in the decommissioning of accident nuclear power station.

Development of JAEA sorption database (JAEA-SDB); Update of sorption/QA data in FY2021

Sugiura, Yuki; Suyama, Tadahiro*; Tachi, Yukio

JAEA-Data/Code 2021-017, 58 Pages, 2022/03

JAEA-Data-Code-2021-017.pdf:1.98MB

Sorption behavior of radionuclides (RNs) in buffer materials (bentonites), rocks and cementitious materials is one of the key processes in a safe geological disposal of radioactive waste because RNs migration in these materials is expected to be retarded by the sorption process. Therefore, it is necessary to understand the sorption process and develop a database compiling reliable data and mechanistic/predictive models so that reliable parameters can be set under a variety of geochemical conditions relevant to a performance assessment (PA). For this purpose, Japan Atomic Energy Agency (JAEA) has developed the database of sorption parameters in bentonites, rocks and cementitious materials. This sorption database (SDB) was firstly developed as an important basis for the H12 PA of a high-level radioactive waste disposal, and have been provided through the Web. JAEA has continued to improve and update the SDB in the view of potential future needs of data focusing on assuring the desired quality level and testing the usefulness of the databases for possible applications to the PA-related parameter setting. This report focuses on updating of the sorption database (JAEA-SDB) as a basis of integrated approach for the PA-related distribution coefficient (Kd) setting and development of mechanistic sorption models. This report also includes an overview of the database structure and contents. Kd data and their quality assurance (QA) results were updated from literature collected with wider ranges. As a result, 8,503 Kd data from 70 references related to the above-mentioned systems were added and the total number of Kd values in JAEA-SDB reached 79,072. The QA/classified Kd data reached about 75.4% for all Kd data in JAEA-SDB. The updated JAEA-SDB is expected to make it possible to give a basis for the next-step PA-related Kd setting.

Challenge to advancement of debris composition and direct isotope measurement by microwave-enhanced LIBS (Contract research); FY2020 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; i-Lab*

JAEA-Review 2021-027, 62 Pages, 2021/11

JAEA-Review-2021-027.pdf:3.06MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2020. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2020, this report summarizes the research results of the "Challenge to advancement of debris composition and direct isotope measurement by microwave-enhanced LIBS" conducted in FY2020. Although LIBS (laser-induced breakdown spectroscopy) is commercially available for application to remote composition measurement, it is not suitable for high radiation environment due to loss in optical fibers derived from the influence of radiation, reduction in laser transmission output, and nuclear fuel debris properties. There are general concerns of the signal strength decrease. In addition, since LIBS is generally considered to be unsuitable for isotope measurement, there are problems to be improved.

Development of microwave-assisted, laser-induced breakdown spectroscopy without a microwave cavity or waveguide

Oba, Masaki; Miyabe, Masabumi; Akaoka, Katsuaki; Wakaida, Ikuo

Japanese Journal of Applied Physics, 59(6), p.062001_1 - 062001_6, 2020/06

https://doi.org/10.35848/1347-4065/ab8b3f

Using a semiconductor microwave source and a coaxial cable for microwave transmission, a compact microwave-assisted, laser-induced breakdown spectroscopy system without a microwave cavity or waveguide was developed. Several types of electrode heads were tested, so that the emission intensity was 50 times larger than without microwave. The limit of the enhancement effect was also found.

A New measuring method for elemental ratio and Vickers hardness of metal-oxide-boride materials based on Laser-Induced Breakdown Spectroscopy (LIBS)

Abe, Yuta; Otaka, Masahiko; Okazaki, Kodai*; Kawakami, Tomohiko*; Nakagiri, Toshio

Proceedings of 2019 International Congress on Advances in Nuclear Power Plants (ICAPP 2019) (Internet), 7 Pages, 2019/05

Since the hardness of fuel debris containing boride from BC pellet in control rod is estimated to be two times higher as that of oxide, such as UO and ZrO, it is necessary to select the efficient and appropriate operation for removal of fuel debris formed in the severe accident of nuclear power plants. We focused on the characteristics of LIBS, an innovative rapid chemical in-situ analysis technology that enables simultaneous detection of B, O, and other metal elements in fuel debris. Simulated solidified melt specimens were obtained in the plasma heating tests (CMMR-0/-2, performed by JAEA) of simulated fuel assembly (ZrO is used to simulated UO pellet, other materials such as stainless steel, BC are same as fuel assembly). The LIBS signals of (B/O)/Zr ratio showed good linear relationship with Vickers hardness. This technique can be also applied as in-situ assessment tool for elemental composition and Vickers hardness of metal-oxide-boride materials.

Laser-induced breakdown spectroscopy and related resonance spectroscopy for nuclear fuel cycle management and for decommissioning of "Fukushima Daiichi Nuclear Power Station"

Wakaida, Ikuo; Oba, Hironori; Miyabe, Masabumi; Akaoka, Katsuaki; Oba, Masaki; Tamura, Koji; Saeki, Morihisa

Kogaku, 48(1), p.13 - 20, 2019/01

By Laser Induced Breakdown Spectroscopy and by related resonance spectroscopy, elemental and isotope analysis of Uranium and Plutonium for nuclear fuel materials and in-situ remote analysis under strong radiation condition for melt downed nuclear fuel debris at damaged core in "Fukushima Daiichi Nuclear Power Station", are introduced and performed as one of the application in atomic energy research field.

Measurement of uranium spectrum using laser induced breakdown spectroscopy; High resolution spectroscopy (470-670 nm)

Akaoka, Katsuaki; Oba, Masaki; Miyabe, Masabumi; Otobe, Haruyoshi; Wakaida, Ikuo

JAEA-Research 2016-005, 40 Pages, 2016/05

JAEA-Research-2016-005.pdf:1.82MB

Laser Induced Breakdown Spectroscopy (LIBS) method is an attractive technique because real-time, in-situ and remote elemental analysis is possible without any sample preparation. The LIBS technique can be applied for analyzing elemental composition of samples under severe environments such as the estimation of impurities in the next generation nuclear fuel material containing minor actinide (MA) and the detection of fuel debris in the post-accident nuclear core reactor of TEPCO Fukushima Daiichi Nuclear Power Plant. For applying LIBS to the analysis of nuclear fuel materials, it is indispensable to identify the emission spectrum and its intensity on impurities intermingled within complex emission spectra of matrix elements such as uranium (U) and plutonium (Pu). In the present study, an echelle spectrometer with a resolving power of 50,000 was employed to identify spectra of natural uranium of wavelength ranging from 470 to 670 nm. The 173 atomic spectra and 119 ionic spectra can be identified. We have confirmed that the measured wavelength and oscillator strength of spectra are consistent with published values.

Measurement of uranium spectrum using laser induced breakdown spectroscopy; High resolution spectroscopy (350-470 nm)

Akaoka, Katsuaki; Oba, Masaki; Miyabe, Masabumi; Otobe, Haruyoshi; Wakaida, Ikuo

JAEA-Research 2015-012, 48 Pages, 2015/10

JAEA-Research-2015-012.pdf:2.22MB

It is important to analyze the next generation nuclear fuel material containing minor actinide (MA) and the fuel debris generated at the accident of Fukushima Daiichi Nuclear Power Station. Therefore, the remote analysis for nuclear fuel materials using Laser Induced Breakdown Spectroscopy (LIBS) is studied. For applying Laser Induced Breakdown Spectroscopy (LIBS) to the analysis of nuclear fuel materials, it is very important to identify the emission spectrum and its intensity on impurities intermingled within complex emission spectra of matrix elements such as uranium (U) and plutonium (Pu). Then, the high resolution spectra of natural uranium of wavelength region of 350-470 nm are measured using LIBS, 247 atomic spectra and 294 single ion spectra were identified. We have confirmed that the measured wavelength and oscillator strength of spectra are consistent with published values.