Surface modification technology of fuel cladding, fresh green to mitigate corrosion and hydrogen-pickup in high-temperature steam environment

Masahiro Furuya*

*この研究の対応する著者

研究成果: Conference contribution

抄録

Fuel claddings would be exposed to a hightemperature steam-flow after a boiled-up sequence of a severe accident of light water reactors as well as spent fuel pools. Zirconium alloys are common cladding material for light water reactors. All the zirconium alloys generate additional heat by the exothermic reaction of oxidation in high-temperature steam. Subsequent temperature rise accelerates the rate of oxidation. The countermeasure to suppress oxidation of zirconium alloy is key to mitigate severe accidents. We invent a surface modification technology of zirconium alloy, Fresh Green, to oxidize and to carbonize a zirconium-alloy surface in the same process. XRD and XPS analyses indicated that a modified layer on zirconium surface is carbon-doped zirconium dioxide, in which some of oxygen atoms in monoclinic zirconium dioxide are replaced by carbon. Experiments are conducted for three representative conditions using an autoclave at relatively high temperature: uniform corrosion at 400 degrees Celsius for 336 hours, nodular corrosion at 500 degrees Celsius for 24 hours, supercritical water corrosion (at 400 degrees Celsius, 24 hours). The Fresh Green surface modification reduces both the oxidation rate and hydrogen-pickup less than a half of that with untreated base material. This is because the Fresh Green layer is closely packed and adhered intimately to the base material. Hydrides were found in the base material without treatment, though they were scarcely observed in the Fresh Green treated specimen. Since the operating temperature of the Fresh Green process is lower than the final annealing temperature in a manufacturing process, the process does not affect the material property and crystal structure. The Fresh Green process, which can be operated at slightly higher pressure than ambient, can be introduced in the conventional manufacturing process without complicity.

本文言語English
ホスト出版物のタイトル2017 International Congress on Advances in Nuclear Power Plants, ICAPP 2017 - A New Paradigm in Nuclear Power Safety, Proceedings
出版社International Congress on Advances in Nuclear Power Plants, ICAPP
ISBN(電子版)9784890471676
出版ステータスPublished - 2017 1 1
外部発表はい
イベント2017 International Congress on Advances in Nuclear Power Plants: A New Paradigm in Nuclear Power Safety, ICAPP 2017 - Fukui and Kyoto, Japan
継続期間: 2017 4 242017 4 28

出版物シリーズ

名前2017 International Congress on Advances in Nuclear Power Plants, ICAPP 2017 - A New Paradigm in Nuclear Power Safety, Proceedings

Other

Other2017 International Congress on Advances in Nuclear Power Plants: A New Paradigm in Nuclear Power Safety, ICAPP 2017
国/地域Japan
CityFukui and Kyoto
Period17/4/2417/4/28

ASJC Scopus subject areas

  • エネルギー工学および電力技術
  • 原子力エネルギーおよび原子力工学

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