Soil dust and bioaerosols as potential sources for resuspended Cs occurring near the Fukushima Dai-ichi Nuclear Power Plant

Ota, Masakazu; Takahara, Shogo; Yoshimura, Kazuya; Nagakubo, Azusa; Hirouchi, Jun; Hayashi, Naho; Abe, Tomohisa; Funaki, Hironori; Nagai, Haruyasu

Journal of Environmental Radioactivity, 264, p.107198_1 - 107198_15, 2023/08

https://doi.org/10.1016/j.jenvrad.2023.107198

One of the current major radiation exposure pathways from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident-fallout is inhalation of the re-suspended Cs occurring in air. While wind-induced soil particle resuspension has been recognized as a primary mechanism of Cs resuspension, studies following the FDNPP accident suggested that fungal spores can be a significant source of the atmospheric Cs particularly in the rural areas such as difficult-to-return zone (DRZ). To elucidate the relative importance of the two resuspension phenomena, we propose a model simulating resuspension of Cs as soil particles and fungal spores, and applied it to DRZ. Our model's calculation showed that soil particle resuspension was responsible for the surface-air Cs observed during winter-spring, but could not account for the higher Cs concentrations observed in summer-autumn. The higher concentrations in the summer-autumn were in general reproduced by implementing fungal spore Cs emission, that replenished low soil particle Cs resuspension in that period. According to our model's concept, Cs accumulation in fungal spores and high spore emission rate characterized by the rural environment were likely responsible for the abundance of spore Cs in the air. It was inferred that the influence of the fungal spores on the atmospheric Cs would last longer since un-decontaminated forests still exist in DRZ.

Verification of detailed core-bowing analysis code ARKAS_cellule with IAEA benchmark problems

Ota, Hirokazu*; Ohgama, Kazuya; Yamano, Hidemasa

Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.30 - 39, 2019/09

A Design study on a mixed oxide fuel sodium-cooled fast reactor core partially loading highly concentrated MA-containing metal fuel

Ohgama, Kazuya; Ota, Hirokazu*; Oki, Shigeo; Iizuka, Masatoshi*

Proceedings of 2019 International Congress on Advances in Nuclear Power Plants (ICAPP 2019) (Internet), 9 Pages, 2019/05

Designing a prototype of the ITER pulse scheduling system

Yamamoto, Tsuyoshi; Yonekawa, Izuru*; Ota, Kazuya*; Hosoyama, Hiroki*; Hashimoto, Yasunori*; Wallander, A.*; Winter, A.*; Sugie, Tatsuo; Kusama, Yoshinori; Kawano, Yasunori; et al.

Fusion Engineering and Design, 87(12), p.2016 - 2019, 2012/12

https://doi.org/10.1016/j.fusengdes.2012.08.005

The ITER pulse scheduling system creates, approves and manage parameters that characterize plasma operation of ITER. JAEA analyzed requirements on the ITER plasma operations based on experience operating the JT-60U and designed essential functions. This system was designed to enable the change and reuse of parameters. The functions to support to check consistency between parameters and to assign parameter values are calculated by the system were proposed. These functions are useful to support operators.

A Four-pellet pneumatic injection system in the JT-60

Hiratsuka, Hajime; Kawasaki, Kozo; Miyo, Yasuhiko; ; ; Shimizu, Masatsugu; ; Onozuka, Masanori*; Shimomura*; ; et al.

Fusion Engineering and Design, 13, p.417 - 424, 1991/00

https://doi.org/10.1016/0920-3796(91)90096-9

no abstracts in English

Characteristic of pellet prodution and injection

Hiratsuka, Hajime; Miyo, Yasuhiko; Kawasaki, Kozo; ;

KEK-Internal-89-7, p.301 - 304, 1989/08

no abstracts in English

Development of fast magnetic valve for JT-60 pellet injector

Hiratsuka, Hajime; Kawasaki, Kozo; Takatsu, Hideyuki; Miyo, Yasuhiko; ; ; Shimizu, Masatsugu; Onozuka, Masanori*; ; ; et al.

Fusion Technology 1988, p.729 - 732, 1989/00

no abstracts in English

In-situ coating device for JT-60

Obara, Kenjiro; Kawasaki, Kozo; Hiratsuka, Hajime; ; ; Miyo, Yasuhiko; Okubo, Minoru; Ota, Mitsuru

JAERI-M 88-117, 77 Pages, 1988/07

JAERI-M-88-117.pdf:2.72MB

no abstracts in English

Development of the methan glow discharge system on JT-60

Kawasaki, Kozo; Hiratsuka, Hajime; Miyo, Yasuhiko; ; ; Maeno, Masaki; Okubo, Minoru

JAERI-M 87-183, 16 Pages, 1987/11

JAERI-M-87-183.pdf:0.6MB

no abstracts in English

Development of highly flexible technology for recovery and transmutation of minor actinide, 2; Study on a MOX fuel fast reactor core loading highly concentrated MA-containing metal fuel

Ohgama, Kazuya; Ota, Hirokazu*; Oki, Shigeo; Ogata, Takanari*; Iizuka, Masatoshi*

no journal, , 

no abstracts in English