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Kuno, Yoshio; Sasamoto, Hiroshi
Materials Research Society Symposium Proceedings, Vol.1124, p.581 - 586, 2009/00
Column experiments were carried out using an artificial fracture within the granite rock in order to investigate the migration behavior of bentonite colloids. A sufficient fraction of colloids was immobilized within the fractured granite in 10
M NaCl solution. In case of comparatively high ionic concentration, retardation of bentonite colloids is expected in the geological medium.
Oi, Takao; Inagaki, Manabu; Kawamura, Makoto; Ebashi, Takeshi
Materials Research Society Symposium Proceedings, Vol.1124, p.407 - 412, 2009/00
In the safety assessment of geological disposal system of radioactive waste, diverse apprehensions have been extracted from the viewpoint of the impact on the safety and the researches relating to those have been carried out strenuously. However, systematical investigation for presenting the relative importance of those has so far scarcely been conducted. The demonstration of the importance is critical issue to contribute the improvement of reliability of safety assessment. In this study, the following investigations were carried out with the goal of developing the systematic approach which can present the relative importance of the apprehensions: (1) Establishment of Total Assessment Work Frame [TAWF], (2) Establishment of the organaization procedure for evaluating the relative importance.
Tachi, Yukio; Seida, Yoshimi; Doi, Reisuke; Xia, X.*; Yui, Mikazu
Materials Research Society Symposium Proceedings, Vol.1124, p.573 - 579, 2009/00
Honda, Akira; Masuda, Kenta; Nakanishi, Hiroshi*; Fujita, Hideki*; Negishi, Kumi*
Materials Research Society Symposium Proceedings, Vol.1124, p.365 - 372, 2009/00
Yoshida, Yasushi*; Yoshikawa, Hideki
Materials Research Society Symposium Proceedings, Vol.1124, p.413 - 420, 2009/00
Ra is one of the important radionuclide for performance assessment of HLW. Concentration of Ra in groundwater is limited by an interaction with calcite. Incorporation of Ra can be evaluated by partition coefficient. In addition to this parameter, a number of surface layers which contribute ion substitution reaction is also necessary for calculation. Therefore experiments were carried out. As a result, a number of surface layers of calcite is estimated as 15to 44. Those values are consistent with estimated value in literature. With this number of layers, the migration analysis of 4n+2 series radionuclides were performed with reaction of calcite. This effect can be evaluated with partition coefficient. As a result, release rates of Ra was largest in their series on an outer surface of engineered barrier and about one order magnitude lower than that for radionuclide of highest release rate at the point of 100 m in rock.
