Management strategy for radioactive waste in the fusion demo reactor

Youji Someya, Kenji Tobita, Hiroyasu Utoh, Nobuyuki Asakura, Yoshiteru Sakamoto, Kazuo Hoshino, Makoto Nakamura, Shinsuke Tokunaga

研究成果: Chapter

13 被引用数 (Scopus)


We have considered a strategy for reducing the radioactive waste generated by the replacement of in-vessel components, such as blanket segments and divertor cassettes, for the fusion DEMO reactor. In the basic case, the main parameters of the DEMO reactor are a major radius of 8.2 m and a fusion power of 1.35 GW. Blanket segments and divertor cassettes should be replaced independently, as their lifetimes differ. A blanket segment comprises several blanket modules mounted to a back-plate. The total weight of an in-vessel component is estimated to be about 6,648 ton (1,575, 3,777, 372, and 924 ton of blanket module, back-plate, conducting shell, and divertor cassette, respectively). The lifetimes of a blanket segment and a divertor cassette are assumed to be 2.2 years and 0.6 years, respectively, and 52,487 tons of waste is generated over a plant life of 20 years. Therefore, there is a concern that the contamination-control area for radioactive waste may need to increase due to the amount of waste generated from every replacement. This paper proposes a management scenario to reduce radioactive waste. When feasible and relevant, back-plates of blanket segment and divertor cassette bodies (628 ton) should be reused. Using the three-dimensional neutron transportation code MCNP, the displacement per atom (DPA) of the SUS316LN back-plates is 0.2 DPA/year and that of the F82H cassette bodies is 0.6 DPA/year. Therefore, the reuse of back-plates and cassette bodies would be possible if re-welding points are arranged under neutron shielding. We found that radioactive waste could be reduced to 20 % when tritium breeding materials are recycled. Finally, we propose a design for the DEMO building that uses a hot cell and temporary storage.

ホスト出版物のタイトルFusion Science and Technology
出版社American Nuclear Society
出版ステータスPublished - 2015 9月 1

ASJC Scopus subject areas

  • 土木構造工学
  • 核物理学および高エネルギー物理学
  • 原子力エネルギーおよび原子力工学
  • 材料科学(全般)
  • 機械工学


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