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Journal Articles

Report of the Special Symposium on the Transport and Diffusion of Contaminants from the Fukushima Dai-ichi Nuclear Power Plant; Present status and future directions

Kondo, Hiroaki*; Yamada, Tetsuji*; Chino, Masamichi; Iwasaki, Toshiki*; Katata, Genki; Maki, Takashi*; Saito, Kazuo*; Terada, Hiroaki; Tsuruta, Haruo*

Tenki, 60(9), p.723 - 729, 2013/09

AA2013-0745.pdf:0.51MB

http://www.metsoc.jp/tenki/pdf/2013/2013_09_0017.pdf

no abstracts in English

Journal Articles

Detection and activity of iodine-131 in brown algae collected in the Japanese coastal areas

Morita, Takami*; Niwa, Kentaro*; Fujimoto, Ken*; Kasai, Hiromi*; Yamada, Haruya*; Nishiuchi, Ko*; Sakamoto, Tatsuya*; Godo, Waichiro*; Taino, Seiya*; Hayashi, Yoshihiro*; et al.

Science of the Total Environment, 408(16), p.3443 - 3447, 2010/06

https://doi.org/10.1016/j.scitotenv.2010.04.001

Times Cited Count：13 Percentile：33(Environmental Sciences)

Iodine-131 ( $^{131}$ I) was detected in brown algae collected off the Japanese coast. The maximum measured specific activity of $^{131}$ I in brown algae was 0.370.010 Bq/kg-wet. Cesium-137 ( $^{137}$ Cs) was also detected in all brown algal samples used in this study. There was no correlation between specific activities of $^{131}$ I and $^{137}$ Cs in these seaweeds. Low specific activity and minimal variability of $^{137}$ Cs in brown algae indicated that past nuclear weapon tests were the source of $^{137}$ Cs. Although nuclear power facilities are known to be pollution sources of $^{131}$ I, there was no relationship between the sites where $^{131}$ I was detected and the locations of nuclear power facilities. Most of the sites where $^{131}$ I was detected were near big cities with large populations. On the basis of the results, we suggest that the likely pollution source of $^{131}$ I, detected in brown seaweeds, is not nuclear power facilities, but nuclear medicine procedures.

JAEA Reports

Effects of overpack corrosion on redox potential of bentonite pore water under geological disposal environment; Important parameter acquisition and a preliminary h analysis (Contract research)

Otsuka, Ichiro; Taki, Hiroshi*; Yamaguchi, Tetsuji; Iida, Yoshihisa; Yamada, Fumika; Inada, Daisuke*; Tanaka, Tadao

JAEA-Research 2008-043, 101 Pages, 2008/03

JAEA-Research-2008-043.pdf:6.24MB

The influence of carbon steel overpack corrosion on redox potential (h) of bentonite pore water under geological disposal environment was investigated. The thermodynamics data of corrosion products, the corrosion rate of carbon steel, and the information on cathode reactions were acquired by experiments and literature survey. We conducted preliminary analysis of h, ascertained the validity of Phreeq C and identified important points on the analysis. Results were summarized as follows. (1) Thermodynamic data of Fe $^{2+}$ , FeOH $^{+}$ , Fe(OH) $_{2}$ (aq), Fe(OH) $_{3}$ $^{-}$ , Fe(OH) $_{4}$ $^{2-}$ , Fe $^{3+}$ , FeS $_{2}$ (pyrite), FeCO $_{3}$ (siderite),Fe(OH) $_{2}$ (s), Fe $_{3}$ O $_{4}$ (magnetite), Fe(cr) were determined by literature survey. The solubility product of Fe $_{2}$ CO $_{3}$ (OH) $_{2}$ was determined experimentally, and thermodynamic data were estimated. (2) The corrosion rate of carbon steel was obtained as a function of pH and sulfide ion concentration. (3) After corrosion tests of carbon steel, no CH $_{4}$ , HS $^{-}$ and H $_{2}$ S, the reduction product of CO $_{3}$ $^{2-}$ and SO $_{4}$ $^{2-}$ ,were not detected in liquid and gas phases. (4) Preliminary analysis showed that the redox couple changed as HS $^{-}$ (aq)/SO $_{4}$ $^{2-}$ , CH $_{4}$ (aq)/CO $_{3}$ $^{2-}$ , H $_{2}$ (aq)/H $_{2}$ O during the evaluation period. After 1000 years, h attained about -500 to -600 mV (vs. NHE) or -750 mV controlled by CH $_{4}$ (aq)/CO $_{3}$ $^{2-}$ ,or H $_{2}$ (aq)/H $_{2}$ O, respectively.

Journal Articles

Development and verification of a reactive transport model for long-term alteration of bentonite-cement-seawater systems

Yamaguchi, Tetsuji; Yamada, Fumika; Negishi, Kumi*; Hoshino, Seiichi; Mukai, Masayuki; Tanaka, Tadao; Nakayama, Shinichi

Physics and Chemistry of the Earth, 33(Suppl.1), p.S285 - S294, 2008/00

It is important to assess long-term alteration of engineered barrier composed of bentonite and cement for the safety assessment of radioactive waste disposal. In order to promote our development of the assessment methodologies, we developed a secondary mineral formation model for cement based materials and a hydraulic conductivity model for bentonite buffer materials. These models were verified by comparing with experimental observations. We also calculated changes in mineralogy of bentonite buffer materials and accompanying changes in the hydraulic conductivity over 10,000 y. We identified the temperature as an important factor dominating the alteration of the buffer. We also identified that the alteration is limited by slow kinetics of the dissolution of montmorillonite and by the diffusive mass transfer. Our calculation showed that the mineralogical change proceeds rather fast during the initial 1,000 y and slows down afterwards, and that salinity of the groundwater has both positive and negative effects on the hydraulic conductivity.

Journal Articles

Crack propagation tests of HIPed DSCu/SS joints for plasma facing components

Hatano, Toshihisa; Goto, Masahiro*; Yamada, Tetsuji*; Nomura, Yuichiro*; Saito, Masakatsu*

Fusion Engineering and Design, 49-50, p.207 - 212, 2000/11

Hoshino, Seiichi; Kadowaki, Mitsushi; Yamada, Fumika*; Mukai, Masayuki; Iida, Yoshihisa; Yamaguchi, Tetsuji; Tanaka, Tadao; Nakayama, Shinichi

no journal, ,

no abstracts in English

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Report of the Special Symposium on the Transport and Diffusion of Contaminants from the Fukushima Dai-ichi Nuclear Power Plant; Present status and future directions

Detection and activity of iodine-131 in brown algae collected in the Japanese coastal areas

Effects of overpack corrosion on redox potential of bentonite pore water under geological disposal environment; Important parameter acquisition and a preliminary h analysis (Contract research)

Development and verification of a reactive transport model for long-term alteration of bentonite-cement-seawater systems

Crack propagation tests of HIPed DSCu/SS joints for plasma facing components

Development of a coupled mass-transport/chemical reaction code for simulating variation in hydraulic conductivity of bentonite buffer in radioactive waste disposal

Modeling of pore-water chemistry as a common base for understanding dissolution of montmorillonite and mass transport in compacted bentonite

Experimental research for long term evaluation on radioactive waste disposal; Progress in 2006

Diffusivity in hardened cement paste altered by contacting aqueous carbonate solutions

Effect of overpack corrosion on redox potential of bentonite pore water, 2; Determination of corrosion rate and cathode reaction by ampoule test

Effect of overpack corrosion on redox potential of bentonite pore water, 1; Estimation of redox potential by geochemical simulation

Experimental research for long term evaluation on radioactive waste disposal; Progress in 2007, Approach to modeling of alteration of cement based materials

Experimental research for long term evaluation on radioactive waste disposal; Progress in 2007

Experimental study on mineralogical changes with interaction between cement and bentonite

Experimental research for long-term assessment of radioactive waste disposal, Status at 2008; Studies on alteration of cement and bentonite