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Journal Articles

Interaction of millisecond kW-class laser pulses with metals and metal oxides; Fundamentals of processing

Daido, Hiroyuki*; Yamada, Tomonori

ILT-APR-34; ILT 2023 Nempo (Internet), p.1 - 5, 2023/07

The decommissioning of Fukushima and the contribution to reconstruction have become national issues. The authors participated in the "Analysis of fine particles generated by laser processing and development of nuclide identification method" (represented by Professor Shuichi Hasegawa of the University of Tokyo), which was adopted as one of the JAEA's publicly solicited projects for this purpose, from FY 2018 to FY 2021 as a subcontractor, The authors conducted research on the observation, evaluation and analysis of the interaction between lasers and various laser-irradiated targets. This report outlines the results of the research in which the authors took part. In the experiments, laser irradiation was carried out on test specimens set up in an irradiation chamber, and shadowgraphs were taken using a high-speed camera and a He-Ne laser. As an example of the experimental results, shadowgraphs of metal (stainless steel) and metal oxide (zirconia), irradiation traces after laser irradiation, and the relationship between laser irradiation power and jet mass are shown, and the interaction between the laser and the metal or metal oxide is discussed. The results will not only contribute to the decommissioning technology of the Fukushima Daiichi NPP, but also to laser processing technology and laser interaction research.

Journal Articles

Development of a laser-driven ultrasonic technology for characterizations of heated and aged concrete samples

Yamada, Tomonori; Daido, Hiroyuki*; Shibata, Takuya

Journal of Nuclear Science and Technology, 59(5), p.614 - 628, 2022/05

 Times Cited Count:1 Percentile:16.97(Nuclear Science & Technology)

Journal Articles

Generation of particles and fragments by quasicontinuous wave fiber laser irradiation of stainless steel, alumina, and concrete materials

Daido, Hiroyuki*; Yamada, Tomonori; Furukawa, Hiroyuki*; Ito, Chikara; Miyabe, Masabumi; Shibata, Takuya; Hasegawa, Shuichi*

Journal of Laser Applications, 33(1), p.012001_1 -  012001_16, 2021/02

 Times Cited Count:0 Percentile:0(Materials Science, Multidisciplinary)

Journal Articles

Study on optical properties of metallic sodium by vacuum ultra violet in UVSOR, 2

Kawaguchi, Munemichi; Saito, Junichi; Daido, Hiroyuki*; Suemoto, Toru*

UVSOR-47, P. 85, 2020/08

To elucidate theoretically the transparent metallic sodium in the vacuum ultraviolet (VUV) spectral range, the aim of this research is to obtain the accurate spectrum using UVSOR. We confirmed the validity for the transmittance measurement in UVSOR by the measurement of transmittance of CaF$$_2$$ windows. However, the transparency phenomenon of VUV in the metallic sodium has never been confirmed by our group. In the future, we will improve the sodium sample and conduct the measurement again.

Journal Articles

Development of a laser chipping technique combined with water jet for retrieval of fuel debris at Fukushima Daiichi Nuclear Power Station

Yamada, Tomonori; Takebe, Toshihiko*; Ishizuka, Ippei*; Daido, Hiroyuki*; Hanari, Toshihide; Shibata, Takuya; Omori, Shinya*; Kurosawa, Koichi*; Sasaki, Go*; Nakada, Masahiro*; et al.

Journal of Nuclear Science and Technology, 56(12), p.1171 - 1179, 2019/12

 Times Cited Count:1 Percentile:11.41(Nuclear Science & Technology)

We describe a new chipping technique combined with a water-jet technique as one of the candidate techniques for the retrieval of fuel debris and support structures as part of the decommissioning of the Fukushima Daiichi Nuclear Power Station. We performed proof-of-principle experiments to demonstrate the removal capability of metal parts, where we focused on the observation of removal processes from a metallic sample using a 5.5-kW continuous wave fiber laser combined with continuous and pulsed water jets.

Journal Articles

Study on optical properties of metallic sodium by vacuum ultra violet in UVSOR

Kawaguchi, Munemichi; Saito, Junichi; Daido, Hiroyuki*; Suemoto, Toru*

UVSOR-46, P. 89, 2019/08

To elucidate theoretically the transparent metallic sodium in the vacuum ultraviolet spectral range, the aim of this research is to obtain the accurate spectrum using UVSOR. The sodium sample maintained metallic luster by designing the special cells to prevent from oxidizing. The results of UVSOR measurement showed the possibility to occur the intransparent layer for vacuum ultraviolet light on the MgF$$_2$$ windows. In the near future, we will improve the sodium sample to solve the problems and conduct the measurement again

Journal Articles

Concrete cutting technology with lasers

Daido, Hiroyuki*; Yamada, Tomonori

Oputoronikusu, 37(12), p.67 - 71, 2018/12

no abstracts in English

Journal Articles

Experimental characterization of concrete removal by high-power quasicontinuous wave fiber laser irradiation

Nguyen, P. L.; Daido, Hiroyuki; Yamada, Tomonori; Nishimura, Akihiko; Hasegawa, Noboru*; Kawachi, Tetsuya*

Journal of Laser Applications, 29(4), p.041501_1 - 041501_11, 2017/11

 Times Cited Count:10 Percentile:61.26(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Introduction to the special issue on "Application of laser techniques to maintenance and repair of the social infrastructure"

Daido, Hiroyuki

Reza Kenkyu, 45(7), p.397 - 398, 2017/07

In this special issue, we present laser techniques applied to maintenance and repair of the social infrastructure such as tunnels, electric power generation and transportation, nuclear facilities. Remote sensing, LIBS, LIDAR, remote technologies coupled with lasers and surface cleaning are reviewed in this issue.

Journal Articles

Demonstration of laser processing technique combined with water jet technique for retrieval of fuel debris at Fukushima Daiichi Nuclear Power Station

Hanari, Toshihide; Takebe, Toshihiko*; Yamada, Tomonori; Daido, Hiroyuki; Ishizuka, Ippei*; Omori, Shinya*; Kurosawa, Koichi*; Sasaki, Go*; Nakada, Masahiro*; Sakai, Hideaki*

Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 3 Pages, 2017/04

In decommissioning of Fukushima Daiichi Nuclear Power Station, a retrieval process of fuel debris in the Primary Containment Vessel by a remote operation is one of the key issues. In this process, prevention of spreading radioactive materials is one of the important considerations. Furthermore, an applicable technique to the process requires keeping of reasonable processing-efficiency. We propose to use the combined technique including a laser light and a water jet as a retrieval technique of the fuel debris. The laser processing technique combined with a repetitive pulsed water jet could perform an efficient retrieval processing. Our experimental result encourages us to promote further development of the technique towards a real application at Fukushima Daiichi Nuclear Power Station.

Journal Articles

Challenge towards the decommissioning of the Fukushima-Daiichi Nuclear Power Plant coupled with recovery of Fukushima

Daido, Hiroyuki

Reza Kenkyu, 45(3), p.135 - 136, 2017/03

I describe how important the challenge to Fukushima Daiichi and recovery of this area. From this point of view, scientific and technological trials originated from the disaster and accident should be based on the mission of Fukushima recovery.

Journal Articles

Contributions to the decommissioning of Fukushima Daiichi Nuclear Power Station by JAEA Naraha Remote Technology Development Center

Daido, Hiroyuki; Kawatsuma, Shinji; Kojima, Hisayuki; Ishihara, Masahiro; Nakayama, Shinichi

Proceedings of 54th Annual Meeting of Hot Laboratories and Remote Handling (HOTLAB 2017) (Internet), 8 Pages, 2017/00

Journal Articles

Full operation of JAEA Naraha Remote Technology Development Center

Daido, Hiroyuki

Hozengaku, 15(3), p.20 - 25, 2016/10

Naraha Remote Technology Development Center is open for various users to contribute to recovery of the coast area of Fukushima as well as the decommissioning of Fukushima Daiichi Nuclear Power Station. The center is located within a distance of 20 km from the Fukushima Daiichi station. This is the first development center funded by the Government near the Fukushima Daiichi. Many people expect that the center plays a significant role to contribute to the decommissioning of Fukushima Daiichi and recovery of Fukushima area from the hazards. The author describe details of the facility and our plan.

Journal Articles

Laser for nuclear decommissioning and its application to maintenance of social infrastructure which is a part of resilience of Japan; Towards utilization of laser techniques under the severe environment and movable laser applications

Daido, Hiroyuki

Kensetsu Kikai, 52(10), p.53 - 58, 2016/10

Laser application for nuclear decommisioning and meintenance of social infrastracture is described.

Journal Articles

Laser processing technology, 1; Innovative progress for atomic nuclear engineering

Daido, Hiroyuki

Denki Gakkai-Shi, 136(7), p.422 - 425, 2016/07

no abstracts in English

Journal Articles

Development of fuel debris removal techniques with lasers

Daido, Hiroyuki

Isotope News, (743), p.7 - 11, 2016/03

no abstracts in English

Journal Articles

Surface modification effects on hydrogen absorption property of a hydrogen storage alloy by short pulse laser irradiation

Abe, Hiroshi; Shimomura, Takuya; Tokuhira, Shinnosuke*; Shimada, Yukihiro*; Takenaka, Yusuke*; Furuyama, Yuta*; Nishimura, Akihiko; Uchida, Hirohisa*; Daido, Hiroyuki; Oshima, Takeshi

Proceedings of 7th International Congress on Laser Advanced Materials Processing (LAMP 2015) (Internet), 4 Pages, 2015/08

A short pulse laser (the nanosecond and femtosecond) was applied to hydrogen absorbing alloys surface layer, and a surface modification experiment was put into effective to aim at improvement of hydrogen adsorption functionally. It was investigated about correlation between an initial hydrogen absorption reaction rate of hydrogen alloys and a laser irradiation in this research. The laser irradiation condition was done with pulse width 100 fsec and energy 0.2 - 3.4 mJ/pulse. It blazed down on hydrogen absorbing alloys (LaNi$$_{4.6}$$Al$$_{0.4}$$) and changed local order in the surface. As a result, the initial hydrogen absorption reaction rate was 1.5 - 3.0 times as fast as a irradiated sample, and the result and laser irradiated sample found out that a hydrogen absorption function improves. A laser irradiation can conclude to be effective in surface modification of the hydrogen storage materials.

Journal Articles

Projection imaging with directional electron and proton beams emitted from an ultrashort intense laser-driven thin foil target

Nishiuchi, Mamiko; Choi, I. W.*; Daido, Hiroyuki; Nakamura, Tatsufumi*; Pirozhkov, A. S.; Yogo, Akifumi*; Ogura, Koichi; Sagisaka, Akito; Orimo, Satoshi; Daito, Izuru*; et al.

Plasma Physics and Controlled Fusion, 57(2), p.025001_1 - 025001_9, 2015/02

 Times Cited Count:2 Percentile:9.07(Physics, Fluids & Plasmas)

Projection images of a metal mesh produced by directional MeV electron beam together with directional proton beam, emitted simultaneously from a thin foil target irradiated by an ultrashort intense laser. The mesh patterns are projected to each detector by the electron beam and the proton beam originated from tiny virtual sources of $$sim$$ 20 micron meter and $$sim$$10 micron meter diameters, respectively. Based on the observed quality and magnification of the projection images, we estimate sizes and locations of the virtual sources for both beams and characterize their directionalities. To carry out physical interpretation of the directional electron beam qualitatively, we perform 2D particle-in-cell simulation which reproduces a directional escaping electron component, together with a non-directional dragged-back electron component, the latter mainly contributes to building a sheath electric field for proton acceleration.

Journal Articles

High order harmonics from relativistic electron spikes

Pirozhkov, A. S.; Kando, Masaki; Esirkepov, T. Z.; Faenov, A. Y.*; Pikuz, T. A.*; Kawachi, Tetsuya; Sagisaka, Akito; Koga, J. K.; Mori, Michiaki; Kawase, Keigo*; et al.

RAL-TR-2015-025, P. 22, 2015/00

Journal Articles

Demonstration of heat resistant fiber Bragg grating sensors based on femtosecond laser processing for vibration monitoring and temperature change

Nishimura, Akihiko; Takenaka, Yusuke*; Furuyama, Takehiro*; Shimomura, Takuya; Terada, Takaya; Daido, Hiroyuki

Journal of Laser Micro/Nanoengineering, 9(3), p.221 - 224, 2014/11

 Times Cited Count:0 Percentile:0(Nanoscience & Nanotechnology)

Heat resistant FBG sensors were developed by femtosecond laser processing to apply them to high temperature operated piping system of nuclear power plants. The FBG sensor was installed on the surface of a steel blade and a vibration test was conducted to detect the resonant vibration frequency of the vibrating blade. The FBG sensor had the heatproof performance at 600$$^{circ}$$C. A frequency stabilized sensing system using a tunable laser was tested for structural health monitoring in daily operation of nuclear power plants. The FBG sensor was installed on the surface of a steel blade for vibration induced strain measurements. Welding, brazing, soldering and noble metal powder adhesive were discussed for molding the FBG sensors.

426 (Records 1-20 displayed on this page)