Laser erosion diagnostics of plasma facing materials with displacement sensors and their application to safeguard monitors to protect nuclear fusion chambers

Koichi Kasuya, Shinji Motokoshi, Seiji Taniguchi, Mitsuo Nakai, Kazutoshi Tokunaga, Waldemar Mroz, Boguslaw Budner, Barbara Korczyc

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

Tungsten and SiC are candidates for the structural materials of the nuclear fusion reactor walls, while CVD poly-crystal diamond is candidate for the window material under the hazardous fusion stresses. We measured the surface endurance strength of such materials with commercial displacement sensors and our recent evaluation method. The pulsed high thermal input was put into the material surfaces by UV lasers, and the surface erosions were diagnosed. With the increase of the total number of the laser shots per position, the crater depth increased gradually. The 3D and 2D pictures of the craters were gathered and compared under various experimental conditions. For example, the maximum crater depths were plotted as a function of shot accumulated numbers, from which we evaluated the threshold thermal input for the surface erosions to be induced. The simple comparison-result showed that tungsten was stronger roughly two times than SiC. Then we proposed how to monitor the surface conditions of combined samples with such diamonds coated with thin tungsten layers, when we use such samples as parts of divertor inner walls, fusion chamber first walls, and various diagnostic windows. We investigated how we might be able to measure the inner surface erosions with the same kinds of displacement sensors. We found out the measurable maximum thickness of such diamond which is useful to monitor the erosion. Additionally we showed a new scheme of fusion reactor systems with injectors for anisotropic pellets and heating lasers under the probable use of W and/or SiC.

Original languageEnglish
Title of host publicationXX International Symposium on High-Power Laser Systems and Applications 2014
EditorsXiaolin Tang, Shu Chen, Chun Tang
PublisherSPIE
ISBN (Electronic)9781628413229
DOIs
Publication statusPublished - Jan 1 2015
Event20th International Symposium on High Power Systems and Applications 2014, HPLS and A 2014 - Chengdu, China
Duration: Aug 25 2014Aug 29 2014

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume9255
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Other

Other20th International Symposium on High Power Systems and Applications 2014, HPLS and A 2014
CountryChina
CityChengdu
Period8/25/148/29/14

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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  • Cite this

    Kasuya, K., Motokoshi, S., Taniguchi, S., Nakai, M., Tokunaga, K., Mroz, W., Budner, B., & Korczyc, B. (2015). Laser erosion diagnostics of plasma facing materials with displacement sensors and their application to safeguard monitors to protect nuclear fusion chambers. In X. Tang, S. Chen, & C. Tang (Eds.), XX International Symposium on High-Power Laser Systems and Applications 2014 [925548] (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 9255). SPIE. https://doi.org/10.1117/12.2065233