Bidirectional reflectance distribution function of recrystallized tungsten mono-block exposed to cyclic heat loading

Hiroki Natsume; Kunpei Nojiri; Shin Kajita; Makoto Fukuda; Tomohiko Ushiki; Hirohiko Tanaka; Tatsuo Sugie; Sin-iti Kitazawa; Takanori Kikuchi; Tomohiro Yokozuka; Noriyasu Ohno; Koichiro Ezato; Takaki Hatae

Nuclear Materials and Energy (Oct 2022)

Bidirectional reflectance distribution function of recrystallized tungsten mono-block exposed to cyclic heat loading

Hiroki Natsume,
Kunpei Nojiri,
Shin Kajita,
Makoto Fukuda,
Tomohiko Ushiki,
Hirohiko Tanaka,
Tatsuo Sugie,
Sin-iti Kitazawa,
Takanori Kikuchi,
Tomohiro Yokozuka,
Noriyasu Ohno,
Koichiro Ezato,
Takaki Hatae

Affiliations

Hiroki Natsume: Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan; Corresponding author.
Kunpei Nojiri: Naka Fusion Institute, National Institutes for Quantum Science and Technology (QST), Naka, Japan
Shin Kajita: Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha, Kashiwa 277-8561, Japan
Makoto Fukuda: Naka Fusion Institute, National Institutes for Quantum Science and Technology (QST), Naka, Japan
Tomohiko Ushiki: Naka Fusion Institute, National Institutes for Quantum Science and Technology (QST), Naka, Japan
Hirohiko Tanaka: Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
Tatsuo Sugie: Nippon Advanced Technology Co., Ltd., Tokai, Naka District, Japan
Sin-iti Kitazawa: Naka Fusion Institute, National Institutes for Quantum Science and Technology (QST), Naka, Japan
Takanori Kikuchi: Naka Fusion Institute, National Institutes for Quantum Science and Technology (QST), Naka, Japan
Tomohiro Yokozuka: Naka Fusion Institute, National Institutes for Quantum Science and Technology (QST), Naka, Japan
Noriyasu Ohno: Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
Koichiro Ezato: Naka Fusion Institute, National Institutes for Quantum Science and Technology (QST), Naka, Japan
Takaki Hatae: Naka Fusion Institute, National Institutes for Quantum Science and Technology (QST), Naka, Japan

Journal volume & issue: Vol. 33
p. 101243

Abstract

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The bidirectional reflectance distribution function (BRDF) of recrystallized tungsten mono-blocks exposed to cyclic heat loading for ITER divertor outer vertical target was measured using a goniophotometer at a wavelength of 473 nm. Laser microscope observations revealed that the surface roughness of the mono-block increased by an order of magnitude after cyclic heat loads of approximately 20 MWm−2. Furthermore, the overall values of BRDF decreased with an increase in cyclic heat loading. A comparison between the modeled and measured BRDFs showed that an additional Lambertian component is necessary to a specular function (microfacet model or Gaussian function) to fit the measured BRDFs when the surface of the mono-blocks becomes rough.

Published in Nuclear Materials and Energy

ISSN: 2352-1791 (Online)
Publisher: Elsevier
Country of publisher: United Kingdom
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Nuclear engineering. Atomic power
Website: http://www.journals.elsevier.com/nuclear-materials-and-energy/

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