Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Nakano, Masanao; Fujita, Hiroki; Mizutani, Tomoko; Nemoto, Masashi; Tobita, Keiji; Kono, Takahiko; Hosomi, Kenji; Hokama, Tomonori; Nishimura, Tomohiro; Matsubara, Natsumi; et al.
JAEA-Review 2018-025, 171 Pages, 2019/02
Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of Japan Atomic Energy Agency, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged from the plant to the atmosphere and the sea during April 2016 to March 2017. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Station of Electric Power Company Holdings, Inc. in March 2011. Appendices present comprehensive information, such as monitoring programs, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes. In addition, the data which were influenced by the accidental release and were exceeded the normal range of fluctuation in the monitoring, were evaluated.
Nakano, Masanao; Fujita, Hiroki; Mizutani, Tomoko; Nemoto, Masashi; Tobita, Keiji; Hosomi, Kenji; Nagaoka, Mika; Hokama, Tomonori; Nishimura, Tomohiro; Koike, Yuko; et al.
JAEA-Review 2017-028, 177 Pages, 2018/01
Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of Japan Atomic Energy Agency, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged from the plant to the atmosphere and the sea during April 2016 to March 2017. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Station of Electric Power Company Holdings, Inc. in March 2011. Appendices present comprehensive information, such as monitoring programs, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes. In addition, the data which were influenced by the accidental release and were exceeded the normal range of fluctuation in the monitoring, were evaluated.
Fujita, Tomoo; Taniguchi, Naoki; Matsui, Hiroya; Tanai, Kenji; Nishimura, Mayuka; Kobayashi, Yasushi; Hiramoto, Masayuki; Maekawa, Keisuke; Sawada, Atsushi; Makino, Hitoshi; et al.
JAEA-Research 2007-045, 140 Pages, 2007/03
This report summarizes the progress of research and development on geological disposal during the surface-based investigation phase (2001-2005) in the Horonobe Underground Research Laboratory project (HOR), of which aims are to apply the design methods of geological disposal and mass transport analysis to actual geological environments and derive future subjects based on the results. The design methods of geological disposal were reviewed based on the recent knowledge and the advertences were identified. Then the parameters for virtual design of engineered barrier system, backfill deposition hole and tunnel were set up based on actual geological conditions obtained from the surface-based investigations in HOR as an example of actual geological environment. The conceptual structure from site investigation and evaluation to mass transport analysis was represented as a work flow at first. Then following this work flow a series of procedures for mass transport analysis were carried out based on actual geological conditions obtained from the surface-based investigations in HOR to illustrate the functioning of the work flow and the applicability of this methodology. Consequently, knowledge that will help follow-up or future execution and planning activities was obtained.
Aoyanagi, Shigeo; Yui, Mikazu; Tanai, Kenji; Kawakami, Susumu; Fujita, Tomoo; Taniguchi, Naoki; Shibata, Masahiro; Konishi, Kazuhiro; Nishimura, Mayuka; Kikuchi, Hirohito*; et al.
JAEA-Review 2006-014, 61 Pages, 2006/03
no abstracts in English
Naganuma, Takeshi*; Iwatsuki, Teruki; Murakami, Yuki; Hama, Katsuhiro; Okamoto, Takuji*; Tanimoto, Daisuke*; Fujita, Yuka*; Watanabe, Fumiko*; Adachi, Nahomi*; Sato, Makoto*
JNC TY7400 2003-001, 116 Pages, 2003/05
The abundance and diversity of groundwater microorganisms was studied in the Tono area, central Japan. Total cell counts were estimated by epifluorescence microscopy. Cell viability, based on cell membrane integrity, respiration-based metabolism, and esterase activity was estimated to be from 0.001% to approximately 100% of the total counts. The distribution of microbial abundance wad related to a variety of environmental factors, including fracture numbers, hydrological, and geochemical conditions in the groundwater. In the groundwater, profiles of redox sensitive solutes such as sulphate and sulphide ions, abundance and viability of microbes, and sulphur isotope rations of sulphate ions suggest that microbial sulphate redution involving organic matter and subsequent pyrite precipiration are dominant redox reactions at the depths of the uranium ore body. Concentrations of both the sulphate and chloride increase with increasing depth. The dissoloved sulphate is surmised to have originated from dissolution of sulphate and sulphide minerals in a geologic marine formation precipitated in marine environments, in the upper part of the sedimentary rocks. Such a redox process in the water-mineral-microbe system is inferred to have continued from the time when the marine formation underwent uplift above sea-level, because sulphate-reducing bacteria can use sulphate ions dissolved in fresh water that infiltrates from the marine formation and organic matter located in the deeper sedimentary rocks. Calculations by using the sulphate-S contents of the rocks and the sulphate dissolution rate suggest that microbial sulphate redution alone could maintain sufficiently reducing conditions of preserve the uranium ore for several hundred thousand years, in the case where a hydrogeological system continues to exist without much change. On the other hand, iron-oxidizing/reducing bacteria seem to play an important role in iron redox cycling in the granite groundwater.
Fukasawa, Tsuyoshi*; Hirayama, Tomoyuki*; Yokoi, Shinobu*; Hirota, Akihiko*; Somaki, Takahiro*; Yukawa, Masaki*; Miyagawa, Takayuki*; Uchita, Masato*; Yamamoto, Tomohiko; Miyazaki, Masashi; et al.
no journal, ,
The seismic integrity of sodium-cooled fast reactor (SFR) designs in nuclear power plants is of paramount importance. Based on the static loading test, this study investigates the force-displacement relationship and load transference in a three-dimensional seismic isolation system that is envisaged for use in reactor buildings. In SFR designs, the necessity for thin-walled structures to maintain high-temperature structure integrity can unintentionally compromise the seismic design. Consequently, addressing horizontal and vertical seismic forces become vital for ensuring seismic resilience. Currently, there are no specific codes or standards governing the integration of Three-dimensional seismic isolation systems into nuclear reactor buildings. However, current guidelines for the design of horizontal seismic isolation systems emphasize the necessity to clarify the force-displacement relationship and load transfer under conditions of superimposed horizontal and vertical loads. This study involves static loading tests performed on a half-scale specimen, which is subjected to horizontal and vertical loads exceeding the design basis ground motions for the SFR. The findings affirm that the system's horizontal supporting function maintains the segregation of horizontal and vertical load transference, even under seismic loads that exceed the design basis ground motions.