Research plan on geosphere stability for long-term isolation of radioactive waste (Scientific program for fiscal year 2023)

Niwa, Masakazu; Shimada, Koji; Sueoka, Shigeru; Fujita, Natsuko; Yokoyama, Tatsunori; Ogita, Yasuhiro; Fukuda, Shoma; Nakajima, Toru; Kagami, Saya; Ogata, Manabu; et al.

JAEA-Review 2023-017, 27 Pages, 2023/10

JAEA-Review-2023-017.pdf:0.94MB

This report is a plan of research and development (R&D) on geosphere stability for long-term isolation of high-level radioactive waste (HLW) in Japan Atomic Energy Agency (JAEA), in fiscal year 2023. The objectives and contents in fiscal year 2023 are described in detail based on the JAEA 4th Medium- and Long-term Plan (fiscal years 2022-2028). In addition, the background of this research is described from the necessity and the significance for site investigation and safety assessment, and the past progress. The plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques.

Feasibility Study on Commercialization of Fast Breeder Reactor Cycle Systems Interim Report of Phase II; Technical Study Report for Reactor Plant Systems

Konomura, Mamoru; Ogawa, Takashi; Okano, Yasushi; Yamaguchi, Hiroyuki; Murakami, Tsutomu; Takaki, Naoyuki; Nishiguchi, Youhei; Sugino, Kazuteru; Naganuma, Masayuki; Hishida, Masahiko; et al.

JNC TN9400 2004-035, 2071 Pages, 2004/06

JNC-TN9400-2004-035.pdf:76.42MB

The attractive concepts for Sodium-, lead-bismuth-, helium- and water-cooled FBRs have been created through using typical plant features and employing advanced technologies. Efforts on evaluating technological prospects of feasibility have been paid for these concepts. Also, it was comfirmed if these concepts satisfy design requierments of capability and performance presumed in the feasibilty study on commertialization of Fast Breeder Reactor Systems. As results, it was concluded that the selection of sodium-cooled reactor was most rational for practical use of FBR technologies in 2015.

Late Holocene coseismic subsidence in the Nobi Plain estimated from sediment core analyses

Niwa, Yuichi*; Sugai, Toshihiko; Ogami, Takashi*; Tajikara, Masayoshi; Yasue, Kenichi; Fujiwara, Osamu*

no journal, , 

no abstracts in English

Depositional environmental changes recorded in the Holocene sequence in the Nobi plain and their implication for the activity of the Yoro fault system, fringing the margine of the plain

Niwa, Yuichi*; Sugai, Toshihiko*; Ogami, Takashi*; Tajikara, Masayoshi*; Yasue, Kenichi; Fujiwara, Osamu*

no journal, , 

Analyses of drilling cores and C-14 ages from a lowland along the Yoro fault system fringing the Nobi plain suggest that five subsidence events occurred in the middle to late Holocene. The cores are represented by a prograding delta sequence that has formed on the footwall side of the Yoro fault system. Vertical changes of sedimentary facies, grain size distribution and Electronic Conductivity (EC) value of sediment samples suggest that temporal relative sea-level rise occurred. Trend of relative-sea level lowering during middle to late Holocene indicates that cause of these sea-level rise events can be coseismic subsidence.

X-ray absorption near edge structure of ATP thin film irradiated with soft X-rays

Fujii, Kentaro; Fujii, Shinichiro*; Kato, Dai*; Tsukimoto, Mitsutoshi*; Akimitsu, Nobuyoshi*; Narita, Ayumi; Nakajima, Takafumi*; Ide, Shunta*; Salam, K. A.*; Niwa, Osamu*; et al.

no journal, ,