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

https://doi.org/10.1080/00223131.2019.1647890

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.

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.

Research on removal technologies of fuel debris and in-vessel structures using laser light (I); 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.

Development of migration prediction system(MIGSTEM) for cationic species of radionuclides through soil layers

Onuki, Toshihiko; Takebe, Shinichi; Yamamoto, Tadatoshi

Journal of Nuclear Science and Technology, 26(8), p.795 - 804, 1989/08

https://doi.org/10.3327/jnst.26.795

no abstracts in English

Study on removal technologies for Fukushima's fuel debris using laser light, 1; Outline of the study

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

no journal, , 

no abstracts in English

Study on removal technologies for Fukushima's fuel debris using laser light, 2; Characteristic evaluation of metal cutting by laser continuous irradiation and assist gas flow

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

no journal, , 

no abstracts in English

Study on removal technologies for Fukushima's fuel debris using laser light, 6; Experiment of laser cutting and crushing of randomly-shaped / metal-ceramics composite

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

no journal, , 

no abstracts in English

Study on removal technologies for Fukushima's fuel debris using laser light, 7; Evaluation of transient temperature characteristics of molten metal during laser cutting process

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

no journal, , 

Study on removal technologies for Fukushima's fuel debris using laser light, 11; Experiment of laser cutting and crushing for indefinite shape and metal-ceramics composite materials in water

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

no journal, , 

no abstracts in English

Evaluation of fiber laser cutting and crushing applied to the removal technology of fuel debris and in-vessel structures

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

no journal, , 

In the decommissioning of the Fukushima Daiichi NPPs, remote handling techniques are necessary to remove the fuel debris which is solidified by mixed molten materials composed of fuels and in-vessel structures. In terms of remote handling, a laser beam can penetrate a narrow gap and it can shoot the substance without reactive force. Thus, a laser has been expected as one of the useful decommissioning tools. In this paper, to evaluate the cutting and crushing performances, we performed thick metal cutting and ceramics crushing using a fiber laser. A continuous wave mode and pulsed mode make it possible to cut a 30 mm thick SS400 steel plate and to crush a 10 mm thick alumina pellet. Moreover, we succeeded to cut a metal-ceramic mixture materials using fiber laser, in combination with x-y-z tri-axes control system and laser scanner. It is hoped that the outcome of the present study would be of some use to develop remote cutting and crushing technique for the decommissioning.