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Amamoto, Ippei
Journal of the Society of Inorganic Materials, Japan, 24(391), p.393 - 401, 2017/11
Glass is a non-crystalline solid, as such, it is relatively easy to change its composition to control its characteristics. The borosilicate glass, which is produced by the addition of boron oxide into sodium-lime glass, possesses excellent heat-resistant properties and mechanical strength. It has a wide variety of uses. The borosilicate glass is applied as the vitrified medium for radioactive wastes to immobilize and stabilize them for long term. The glass form which is loaded with high-level radioactive waste is called the vitrified waste. This paper classified the radioactive waste and describes treatment and production methods of vitrified waste, its characteristics, disposal method and also introduces alternative vitrified medium.
Tanaka, Satoru*
JNC TJ8400 2000-003, 62 Pages, 2000/02
JNC-TJ8400-2000-003.pdf:11.88MB
For the safety assessment of radioactive waste disposal, it is important to elucidate the effect of colloids on radionuclide migration, which are released with dissolution of cementitious materials composing engineered barricr. In the previous work, we identified and characterized the colloidal particles in the solutions contacting cement hydrates, OPC and low-alkaline cement paste, and observed the release of the colloid particle. In the present work, we performed same experiments as the last year to confirm the reproducibility of the colloid release. We studied the leaching behavior of the colloid when OPC and low-alkaline cement past contact water flow. Furthermore, the effect of an alumina particle was studied, which is used as a barrier material for colloid migration. The following conclusions were derived: (1)In the solution contacting cement paste, the small amount of particles, which are considered as CaCO
or silicate colloids were observed. Thus, the reproducibility of the last work was confirmed. (2)The leaching of colloid in the solution was confirmed by water flow through the cement paste. The concentration of particle was as low as 10
10
mL
. (3)Al
0 powder, with the diameter of 200150
m, was found to be effective to some extent as a barrier for a colloid migration from low-alkaline cement paste.
Masumoto, Kazuhiko*; Matsushita, Tomoaki*; Takeuchi, Ryuji
no journal, ,
The monitoring of groundwater condition in fractures around the rock cavern is important for safety assessment for high level radioactive waste. The GPR (Ground Penetrating Radar) method is unique technique to survey the water condition in fractures, indirectly, and with no disturbance of original groundwater condition. The authors conducted the GPR monitoring of infiltration of saline water on the side wall of the 500m access tunnel of Mizunami Underground Research Laboratory. The results showed that the difference of saline concentration in fractures caused the change of the reflection wave form and the intense of spectrum due to the results of spectrum analysis of reflection wave.
Kubota, Kenji*; Morifuji, Yohei*; Aoyagi, Kazuhei; Sugita, Yutaka
no journal, ,
We performed in-situ experiments such as seismic and electrical resistivity tomography, geological survey and so on before, during, and 11 years after excavation of galleries at 140 and 250 m depth in an area of soft sedimentary rock in the Horonobe Underground Research Laboratory, Hokkaido, Japan. The results demonstrate that the extent of fractures and unsaturated zone induced by the gallery excavation were clarified. The extent of fractures related with EDZ was limited in about 0.45 m from the gallery wall in the 140 m gallery and to about 1 m from the gallery wall in the 250 m gallery. The extent of the unsaturated zone related with EdZ was about 1 m in the 140 m gallery, but it was not appeared in the 250 m gallery. Such changes induced by the gallery excavation occurred within one year after gallery excavation. On the other hand, the extension of the developed fractures and unsaturated zone was hardly clarified in about 11 years after gallery excavation.
Yamaguchi, Fumie
no journal, ,
no abstracts in English