Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Tochigi, Yoshikatsu; Kogawa, Noritaka*; Mukai, Satoru*; Jintoku, Takashi*; Sasamoto, Hiroshi; Shibata, Masahiro; Yui, Mikazu
JAEA-Research 2007-024, 27 Pages, 2007/03
JAEA-Research-2007-024.pdf:1.83MB
In the safety assessment of high-level radioactive waste (HLW) geological disposal, it is important to understand diffusion behavior of radionuclides for evaluation of retardation capacity in the host rock. In this study, non steady state diffusion experiments with non-sorbing ion ware carried out using several granitic rock samples of different length and the matrix diffusion depth was evaluated. As the results of experiment, it is confirmed that the non-sorbing ion can diffuse into the unaltered zone of granitic rock at least about 200 mm in depth and almost same diffusion coefficient is estimated for all rock samples independent of length. Based on these results, it is expected that matrix diffusion of nuclides is acting on a scale of several dozens of centimeters in the granitic rock.
Taniguchi, Naoki; Kogawa, Noritaka*; Maeda, Kazuto*
JAEA-Research 2006-051, 60 Pages, 2006/08
JAEA-Research-2006-051.pdf:6.45MB
It is necessary to understand the corrosion behavior of candidate overpack materials to plan the in-situ engineered barrier test at underground laboratory constructing at Horonobe and to design the overpacks suitable to Horonobe environment. The preliminary corrosion tests of carbon steel which is a candidate material for overpacks were carried out using artificial groundwater and actual groundwater sampled at Horonobe. As the results of anodic polarization experiments, the anodic polarization curves of carbon steel in buffer material were active dissolution type, and the corrosion type of carbon steel in Horonobe groundwater environment was expected to be general corrosion. The results of immersion test under air equilibrium condition and anaerobic condition showed that the corrosion rate and the degree of corrosion localization were not exceeded the data obtained in previous studies. Based on the experimental results, it was confirmed that the corrosion assessment model and assumed corrosion rate in second progress report (H12 report) can be applied to the assessment for Horonobe groundwater condition.
Kitao, Hideo*; Kogawa, Noritaka*
JNC TJ6420 2003-010, 156 Pages, 2003/02