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Tanaka, Satoru*; Nagasaki, Shinya*; Nakata, Kotaro*; Oda, Takuji*; Kameda, Jun*; Kamei, Gento; Tachi, Yukio
JNC TY8400 2003-008, 88 Pages, 2003/05
JNC-TY8400-2003-008.pdf:1.29MB
Redox reactions between Cr(VI) and iron(II) chloride (FeCl2) and those between Cr(VI) and magnetite (Fe(II)1Fe(III)2O4) were observed as a preliminary study. According to the experimental results, it was suggested that the redox reactions were promoted more than the amount of Fe(II) on magnetite surface because of electron transfer from internal Fe(II) to magnetite surface. The results were quantitatively supported from quantum chemical calculations. Redox reactions between Np(V) and magnetite and the reduction of Np to tetravalent were observed, while those between Np(V) and FeCl2 were not observed obviously. It was observed that the reactions were promoted rapidly when the magnetite / solution ratio and the temperature were high, and the rate constant of the reactions was obtained. Furthermore, it was found that hydrogen gas and hydrogen ion were generated with crushing the quartz in an inert gas atmosphere.
Tokunaga, Tomochika*; Taniguchi, Makoto*; Shimada, Jun*; Zhang, J.*; Inaba, Kaoru; Saegusa, Hiromitsu; Iwatsuki, Teruki
JNC TY7400 2003-003, 142 Pages, 2003/05
JNC-TY7400-2003-003.pdf:6.85MB
One of the major concerns for the high-level radioactive waste disposal is the possibility of the radionuclides to reach biosphere by groundwater flow. Recent research results have shown that the fresh groundwater discharge from subsea formations are widespread phenomena, thus, it is necessary to evaluate the submarine groundwater discharge as possible pathways of contaminant discharge towards the biosphere. It is also important to unravel the groundwater flow and associated material transport at the coastal area and subsea formations. To better understand the groundwater flow processes and the submarine groundwater discharge, we have conducted the hydrological, hydrogeological, geochemical, and numerical modeling studies at the Kurobe alluvial fan and its offshore, Toyama Prefecture, Japan. In this report, the results of the following research activities are presented:1)Development and application of a method to detect the locations of the submarine groundwater discharge.2)Development and application of a method to collect uncontaminated groundwater samples from subesa formations.3)Measurements of submarine groundwater dischange fluxes by automated seepage meter.4)Hydrological and geochemical studies for groundwater flow at the coastal area.5)Geochemical studied to understand sources of fresh submarine groundwater discharge.6)Extamination of groundwater flow and submarine groundwater discharge using methane concentration and carbon isotope ratio.7)Numerical modeling studies for coastal groundwater flow system.