Studies of long term alteration of volcanic glass and bentonite and of long term immobility of iodine in Geological medium
Futakuchi, Katsuhito*; not registered; not registered; not registered; Hashimoto, Shuji*
The alteration characteristics of volcanic glass and bentonite and immobility of iodine in geological medium are investigated as a part of the natural analogue study of geological disposal of high-level radioactive waste. For the study of volcanic glass, volcanic ashes (08) are collected at Kamogawa area in Chiba Prefecture which ejected Pleistocene (ca. 1.0 Ma.) to examine the hydration in underground condition. Optical analysis, espetially reflaction index measurement show that volcanic ashes (08) were wholly hydrated. For the study of bentonite, marine argillaceous rocks in Nishikubiki area, Niigata Prefecture have been studied to determine the thermal history of this area. In order to estimate the temperature on contact of inturusive body and argillaceous rocks, measurement of homoginized temperature of fluid inclusion and observation under the optical microscope. For the study of iodine immobility in geological medium, iodine-bearing groundwater in Mobara Gas field, Chiba Prefecture, were discussed.