Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 154

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Provision of laser irradiation conditions for melting and solidification processes using computational science simulation code SPLICE

Muramatsu, Toshiharu

Sumato Purosesu Gakkai-Shi, 8(1), p.4 - 8, 2019/01

no abstracts in English

Journal Articles

Provision of laser irradiation conditions for melting and solidification processes using computational science simulation code SPLICE

Muramatsu, Toshiharu

Nippon Kikai Gakkai 2018-Nendo Nenji Taikai Koen Rombunshu (DVD-ROM), 5 Pages, 2018/09

A general-purpose three-dimensional thermohydraulics computer science simulation code SPLICE was developed at JAEA and designed to deal with gas-liquid-solid consolidated incompressible viscous flows with a phase change process in various laser applications. The results obtained from various numerical simulations using the SPLICE code are very encouraging in the sense that the SPLICE code would be used as one of the efficient front-loading tools to reduce overhead loads in laser processing.

Journal Articles

Computational science simulations for laser coating processes

Muramatsu, Toshiharu

Reza Kako Gakkai-Shi, 25(2), p.81 - 85, 2018/06

no abstracts in English

Journal Articles

Evaluation of melting and solidification processes by laser irradiations using a computational science simulation code SPLICE

Muramatsu, Toshiharu

Dai-89-Kai Reza Kako Gakkai Koen Rombunshu, p.115 - 119, 2018/05

no abstracts in English

Journal Articles

Establishment of Fukui Smart Decommissioning Technology Demonstration Base; Decommissioning Technology Demonstration Test Center (tentative name)

Muramatsu, Toshiharu; Sano, Kazuya; Terauchi, Makoto

Dekomisshoningu Giho, (57), p.65 - 74, 2018/03

The Decommissioning Technology Demonstration Test Center (tentative name) is established as a central facility of "Fukui Smart Decommissioning Technology Demonstration Base" which was adopted by the support policy "Regional Science and Technology Demonstration Base Establishment Project" of the Ministry of Education, Culture, Sports, Science and Technology in FY 2016 supplementary budget. This facility is a base to train local companies about technology concerning the decommissioning of nuclear power plants and for the industry, academia and government to contribute to the development of the regional economy and solving the problem of decommissioning under one roof, and consists of decommissioning dismantling technology verification field, laser processing advanced field and decommissioning mock-up test field. The papers introduce the outline of the facilities in each of these fields.

Journal Articles

Computational science simulation of laser material processing

Muramatsu, Toshiharu

Hikari Araiansu, 28(12), p.31 - 35, 2017/12

no abstracts in English

Journal Articles

Front-loading for metal powder additive manufacturing processes with a computational science simulation code SPLICE

Muramatsu, Toshiharu; Aoyagi, Yuji*; Yoshiuji, Takahiro*

Nippon Kikai Gakkai 2017-Nendo Nenji Taikai Koen Rombunshu (DVD-ROM), 4 Pages, 2017/09

A general-purpose three-dimensional thermohydraulics numerical simulation code SPLICE was developed at Japan Atomic Energy Agency and designed to deal with gas-liquid-solid consolidated incompressible viscous flows with a phase change process in various laser applications, such as welding, coating, cutting, etc. The result obtained from metal powder laser additive manufacturing simulations is very encouraging in the sense that the SPLICE code would be used as one of efficient tools to provide the laser irradiation conditions.

Journal Articles

Industry development activities and applied laser research activities at Fukui branch of Japan Atomic Energy Agency

Furusawa, Akinori; Takenaka, Yusuke*; Nishimura, Akihiko; Mizutani, Haruki; Muramatsu, Toshiharu

Nippon Hozen Gakkai Dai-14-Kai Gakujutsu Koenkai Yoshishu, p.479 - 480, 2017/08

Industry development activities on applied laser research held at Fukui branch of Japan Atomic Energy Agency are reported. Industry development is inevitable in long-term vision and strategy for developing maintenance technology and establishing decommissioning technology. Fukui branch of JAEA has organized public seminar offering businesses to promote these activities and technology exchange for years. Here some examples offered in the current seminar are introduced concerning with laser technology. Finally, our goal and important point of view are discussed.

Journal Articles

Computational science simulations of laser coating processes using a metal powder direct injection system

Muramatsu, Toshiharu

Reza Kenkyu, 44(12), p.799 - 803, 2016/12

no abstracts in English

Journal Articles

Computational science simulation of laser material processing and provision of their irradiation conditions

Muramatsu, Toshiharu

KANRIN, 68, p.14 - 18, 2016/09

no abstracts in English

Journal Articles

Front-loading method for laser processing of metallic materials with a digital mock-up system

Muramatsu, Toshiharu

Dai-84-KaiReza Kako Gakkai Koen Rombunshu, p.113 - 116, 2016/01

A general-purpose three-dimensional thermohydraulics numerical simulation code SPLICE was developed at Japan Atomic Energy Agency and designed to deal with gas-liquid-solid consolidated incompressible viscous flows with a phase change process in various laser applications, such as welding, coating, cutting, etc. The result obtained from laser coating simulations is very encouraging in the sense that the SPLICE code would be used as one of efficient front-loading tools for related to the laser coating processes.

Journal Articles

Computational science simulation of laser materials processing and provision of their irradiation conditions

Muramatsu, Toshiharu

RIST News, (60), p.22 - 27, 2016/01

no abstracts in English

JAEA Reports

A Study on laser welding of ferritic/martensitic steel (PNC-FMS) for fast reactor fuel assemblies

Kono, Fumiaki; Sogame, Motomu; Yamada, Tomonori; Shobu, Takahisa; Naganuma, Masayuki; Ozawa, Takayuki; Muramatsu, Toshiharu

JAEA-Technology 2015-004, 57 Pages, 2015/03

JAEA-Technology-2015-004.pdf:20.87MB

Laser welding of ferritic/martensitic steel (PNC-FMS) sheets with different thicknesses (2 mm and 5 mm) was examined to investigate the weldability between the inner and outer duct in fast reactor fuel assemblies with inner duct structure (FAIDUS); the objective of the inner duct is to avoid the re-criticality in case of the core melting accident. Laser-spot and melt-run welding was performed at various laser powers, welding times and velocities to find out the appropriate welding conditions with few defects and enough penetration depth. As for the spot welding, furthermore, slow cooling rate or pulsed laser irradiation could reduce the crack and porosity in the welded zone. The strain of the welded zone almost disappeared and the hardness was comparable with that of the base metal by applying post welding heat treatment at 690 $$^{circ}$$C for 103 min. In addition, the shear strength of welded joints was confirmed to be sufficiently higher than the provisional allowance shear stress. These results indicate that laser welding would be probably applied to the PNC-FMS inner and outer ducts.

JAEA Reports

Research on interaction of laser light and non-metals; Evaluation of laser irradiation behavior to concrete

Yamada, Tomonori; Muramatsu, Toshiharu

JAEA-Research 2014-026, 28 Pages, 2015/02

JAEA-Research-2014-026.pdf:18.03MB

In this study the response of hardened cement pastes, which is a major component of concrete, to laser irradiation was investigated under various experimental conditions aiming at the future application to "laser-processing" of concrete. (1) Evaluation of water-cement ratio for laser irradiation. It was found that hardened cement paste subjected to laser irradiation explodes very easily to be hollowed in all the experimental conditions; this response is applicable to "laser-drilling" of a hardened cement paste. (2) Evaluation of the kind of mortar for laser irradiation. Totally 75 laser irradiation tests for fixed mortar blocks were performed with combinations of following experimental conditions: fine aggregate in the mortar blocks was either of quartz, limestone, or Nachiguro-ishi. Although it was found that all kinds of the mortar fuse under laser irradiation after all, difference in the response to laser irradiation among the mortars was also found.

JAEA Reports

Research on removal technologies of fuel debris and in-vessel structures using laser light, 2; Research activities on FY2013

Muramatsu, Toshiharu; Yamada, Tomonori; Hanari, Toshihide; Takebe, Toshihiko; Nguyen, P. L.; Matsunaga, Yukihiro

JAEA-Research 2014-018, 41 Pages, 2014/09

JAEA-Research-2014-018.pdf:42.21MB

In decommissioning works of the Fukushima Daiichi Nuclear Power Plants, it is required that fuel debris solidifying mixed materials of fuels and in-vessel structures should be removed. The fuel debris is considered to have characteristics, such as indefinite shapes, porous bodies, multi-compositions, higher hardness, etc. from the knowledge in the U.S. and the Three Mile Island nuclear power plant. Laser lights are characterized by higher power density, local processability, remote controllabilitiy, etc. and can be performed thermal cutting and crushing-up for various materials which does not depend on fracture toughness. This report describes a research program and research activities in FY2013 aiming at developing removal system of fuel debris by the use of laser lights.

JAEA Reports

Research on removal technologies of fuel debris and in-vessel structures using laser light, 1; Research plan and research activities on FY2012

Muramatsu, Toshiharu; Yamada, Tomonori; Hanari, Toshihide; Takebe, Toshihiko; Matsunaga, Yukihiro

JAEA-Research 2013-024, 49 Pages, 2013/08

JAEA-Research-2013-024.pdf:6.63MB

In decommissioning works of the Fukushima Daiichi Nuclear Power Plants, it is required that fuel debris solidifying mixed materials of fuels and in-vessel structures should be removed. The fuel debris is considered to have characteristics, such as indefinite shapes, porous bodies, multi-compositions, higher hardness, etc. from the knowledge in the U.S. and the Three Mile Island nuclear power plant. Laser lights are characterized by higher power density, local processability, remote controllabilitiy, etc. and can be performed thermal cutting and crushing-up for various materials which does not depend on fracture toughness. This report describes a research program and research activities in FY2012 aiming at developing removal system of fuel debris by the use of laser lights.

Journal Articles

Numerical simulation of laser processing

Yamada, Tomonori; Yamashita, Susumu; Sugihara, Kenta; Muramatsu, Toshiharu

Purazuma, Kaku Yugo Gakkai-Shi, 89(7), p.500 - 506, 2013/08

no abstracts in English

Journal Articles

In-situ X-ray observation of molten pool depth during laser micro welding

Yamada, Tomonori; Shobu, Takahisa; Nishimura, Akihiko; Yonemoto, Yukihiro; Yamashita, Susumu; Muramatsu, Toshiharu

Journal of Laser Micro/Nanoengineering, 7(3), p.244 - 248, 2012/11

Small size and high-performance fiber lasers enable in-situ flaw sizing and repairs at nuclear power plants. In quantum beam science directorate, the new probing system was developed to treat micro cracks at the welded section of heat exchanger tubes, where a fiber laser beam passed through a composite-type optical fiber scope. Molten pool's diameter by laser welding gradually expanded more than the width of the micro crack's crevice caused by stress corrosion cracking. In this work, we have carried out in-situ X-ray observation of inside materials during laser welding. In-situ observation of inside materials during fiber laser welding provides a useful knowledge of repair welding because bubbles and cracks which cause the poor weld was clearly observed in non-destructive. This is very effective for control of weld defect and investigation of the mechanisms. As a result, we are able to confirm the molten pool depth of butt welding for heat exchanger units using the new probing system.

Journal Articles

Thermohydraulic aspects in laser welding and cutting processes

Muramatsu, Toshiharu

Proceedings of 31th International Congress on Applications of Lasers & Electro-Optics (ICALEO 2012) (CD-ROM), p.661 - 669, 2012/09

A general-purpose three-dimensional thermohydraulics numerical simulation code SPLICE was developed at JAEA (Japan Atomic Energy Agency) and designed to deal with gas-liquid-solid consolidated incompressible viscous flows with a phase change process in various laser applications, such as welding, piercing, drilling, cutting, etc. The code solves mass, momentum and energy conservation equations simultaneously in a finite difference form to evaluate various complex phenomena, such as a laser light-material interaction, liquid metal thermohydraulics in welded pond with a mushy zone, residual stress characteristics in welding processes, etc. Applications of the SPLICE code reveal considerable thermohydraulic aspects in the laser welding and cutting processes. The result obtained in this work is very encouraging in the sense that the SPLICE code would be used as one of the efficient tools for simulating the complex phenomena related to the laser welding and cutting processes.

Journal Articles

Numerical simulation of thermohydraulic characteristics of dross ejection process in laser steel cutting

Sugihara, Kenta; Nakamura, Yasuyuki; Ogawa, Takemitsu; Muramatsu, Toshiharu

Proceedings of 20th International Conference on Nuclear Engineering and the ASME 2012 Power Conference (ICONE-20 & POWER 2012) (DVD-ROM), 7 Pages, 2012/07

Numerical simulation code, based on multi-phase thermohydraulics, has been being developed with a goal of a control and prediction for the laser cutting process. A thermohydraulic numerical simulation of the laser steel cutting was carried out to confirm an assist gas and sweep velocity effect to the cutting performance. The performance was evaluated, based on temperature profile and cutting front formation. Simulation results were as follows. If there was no effect of dross ejection by assist gas, a laser light was absorbed into molten steel stagnated in the kerf. Therefore, there was less laser heat input to a solid surface directly. Then, heat transport to the back side of steel plate got delayed. In the case of faster sweep velocity, delay of heat conduction and failure cut were confirmed at behind the cut starting position of the steel plate. Failure cut at the position was observed in our experiments. From these results, it was concluded that the thermohydraulics in the kerf takes important role for not only dross ejection but also promotion of heat input at solid surface.

154 (Records 1-20 displayed on this page)