Abstracts 12) 40067 – An Analytical Model <strong>on</strong> the Sealing Performance of Space for the Design of Buffer Material and Backfill Material Haruo Sato, JAEA (Japan) <str<strong>on</strong>g>The</str<strong>on</strong>g> self-sealing functi<strong>on</strong> of spaces between buffer material and overpack, tunnel wall and disposal pit by swelling occurred with water penetrati<strong>on</strong> is expected for bent<strong>on</strong>ite which will be used as buffer material and part of the backfill material in the geological of high-level radioactive waste in Japan. <str<strong>on</strong>g>The</str<strong>on</strong>g> clearance filling properties of Na-bent<strong>on</strong>ite for buffer material and backfill material specificati<strong>on</strong>s have been studied for distilled water and saline water c<strong>on</strong>diti<strong>on</strong>s, for example, it is reported that Na-bent<strong>on</strong>ite seals clearance even under saline water c<strong>on</strong>diti<strong>on</strong>s in a range of effective bent<strong>on</strong>ite densities which are higher than 1.3 kg/dm3, for a bent<strong>on</strong>ite dry density of 1.8 kg/dm3 and a clearance ratio (volumetric ratio of clearance volume to total volume including pore and the clearance) of 10 % (1.11 in volumetric swelling ratio: Rvs) in experiments for Kunigel-V1 (Na-m<strong>on</strong>tmorill<strong>on</strong>ite c<strong>on</strong>tent ca. 50 wt.%). Although such informati<strong>on</strong> is useful for judging whether clearance is filled, the filling properties of bent<strong>on</strong>ite depend <strong>on</strong> groundwater c<strong>on</strong>diti<strong>on</strong>, silica sand c<strong>on</strong>tent, m<strong>on</strong>tmorill<strong>on</strong>ite c<strong>on</strong>tent in the bent<strong>on</strong>ite and the bent<strong>on</strong>ite dry density, even though at the same effective bent<strong>on</strong>ite density. In the present study, the author c<strong>on</strong>structed an analytical model <strong>on</strong> the clearance filling performance for the design of buffer material and backfill material, based <strong>on</strong> the swelling properties of Na-m<strong>on</strong>tmorill<strong>on</strong>ite which is the clay mineral c<strong>on</strong>stituent of bent<strong>on</strong>ite. In the modelling, experimental data <strong>on</strong> the Rvs of bent<strong>on</strong>ite (Kunigel-V1) reported so far were analyzed. C<strong>on</strong>sequently, it was found that dry density of the bent<strong>on</strong>ite when the free swelling reached equilibrium state was approximately in the range of 0.204-0.241 kg/dm3 for distilled water c<strong>on</strong>diti<strong>on</strong>. <str<strong>on</strong>g>The</str<strong>on</strong>g>se dry densities are equivalent to the range of 0.106-0.126 kg/dm3 in m<strong>on</strong>tmorill<strong>on</strong>ite partial density. On the other hand, the Rvs of bent<strong>on</strong>ite decreased for saline water c<strong>on</strong>diti<strong>on</strong>. Based <strong>on</strong> these experimental data for Rvs, the author derived an analytical expressi<strong>on</strong> to be able to calculate Rvs values against various dry densities and bent<strong>on</strong>ites (different m<strong>on</strong>tmorill<strong>on</strong>ite and silica sand c<strong>on</strong>tents), and showed the manner for judging whether clearance is sealed for an arbitrary clearance ratio. In the paper, the author shows the calculated results of Rvs versus dry density under various c<strong>on</strong>diti<strong>on</strong>s. 13) 40069 – Current Status of Hor<strong>on</strong>obe URL Project in C<strong>on</strong>structi<strong>on</strong> Phase Hir<strong>on</strong>obu Abe, Koichiro Hatanaka, JAEA (Japan) Hor<strong>on</strong>obe URL project has been pursued by JAEA (Japan Atomic Energy Agency) to establish and dem<strong>on</strong>strate site characterizati<strong>on</strong> methodologies, engineering technologies, and safety assessment methodologies for HLW geological disposal in relevant geological envir<strong>on</strong>ment with sedimentary rock and saline groundwater distributing in Hor<strong>on</strong>obe area, Hokkaido, Japan. In the Hor<strong>on</strong>obe URL project, surface-based investigati<strong>on</strong> phase (Phase I) has already completed in the year 2005, and then c<strong>on</strong>structi<strong>on</strong> phase (Phase II) has initiated in the same year. Currently, c<strong>on</strong>structi<strong>on</strong> of the underground facilities such as shafts/drifts which were designed in Phase I, investigati<strong>on</strong>s of the geological envir<strong>on</strong>ment in the excavated shafts/drifts and c<strong>on</strong>firmati<strong>on</strong> of applicability of engineering technologies has been alternately carried out as Phase II activities of the project. At the end of January, 2010, ventilati<strong>on</strong> shaft has reached at the depth of GL-250m and east access shaft has reached at the depth of GL210m. C<strong>on</strong>cerning horiz<strong>on</strong>tal drifts, c<strong>on</strong>structi<strong>on</strong> of GL-140m gallery with total length of 184m has completed and GL-250m gallery has partially c<strong>on</strong>structed with the length of 42m. During the c<strong>on</strong>structi<strong>on</strong> so far, m<strong>on</strong>itoring for the c<strong>on</strong>structi<strong>on</strong> safety such as c<strong>on</strong>vergence measurements, tunnel wall observati<strong>on</strong>, sampling of groundwater and rock, investigati<strong>on</strong>s for evaluating excavati<strong>on</strong> damaged z<strong>on</strong>e al<strong>on</strong>g shaft/drift were carried out. In additi<strong>on</strong>, shotcrete c<strong>on</strong>structi<strong>on</strong> test and grout injecti<strong>on</strong> test by using low alkaline cement material were carried in the horiz<strong>on</strong>tal drifts. In this paper, status of the URL c<strong>on</strong>structi<strong>on</strong> and research activities menti<strong>on</strong>ed above are outlined as the current achievement of the Hor<strong>on</strong>obe URL project. 14) 40074 – Development of New Ultrafiltrati<strong>on</strong> Techniques Maintaining In-Situ Hydrochemical C<strong>on</strong>diti<strong>on</strong>s for Colloidal Study Daisuke Aosai, Yuhei Yamamoto, Takashi Mizuno, JAEA (Japan) Chemical state of elements in groundwater is <strong>on</strong>e of the most important informati<strong>on</strong> for understanding behavior of elements in underground envir<strong>on</strong>ment. Chemical state of elements c<strong>on</strong>trolled mainly by groundwater physico-chemical parameters. Because the change of physico-chemical parameters of groundwater, due to pressure release and oxidati<strong>on</strong> during sampling, causes changes in chemical state of elements, systematic methodologies for understanding in situ chemical state is required. In this study, in order to understand chemical state of elements in groundwater, an ultrafiltrati<strong>on</strong> instrument for maintaining in-situ pressure and anaerobic c<strong>on</strong>diti<strong>on</strong>s was developed. <str<strong>on</strong>g>The</str<strong>on</strong>g> instrument developed in this study for ultrafiltrati<strong>on</strong> made of passivated Stainless Used Steel (SUS) materials, was designed to keep groundwater samples maintaining in-situ pressure/anaerobic c<strong>on</strong>diti<strong>on</strong>s. Ultrafiltrati<strong>on</strong> of groundwater was c<strong>on</strong>ducted at a borehole drilled from the 200 mbGL (meters below ground level) Sub-stage at a depth of 200 m at the Mizunami Underground Research Laboratory. Chemical analyses of groundwater were also c<strong>on</strong>ducted using samples filtered under both pressurized/anaerobic and atmospheric c<strong>on</strong>diti<strong>on</strong>s and passivated SUS materials with different elapsed times after passivati<strong>on</strong>. <str<strong>on</strong>g>The</str<strong>on</strong>g> results indicate that our ultrafiltrati<strong>on</strong> method is suitable for collecti<strong>on</strong> of filtered groundwater and passivati<strong>on</strong> is an essential treatment before ultrafiltrati<strong>on</strong>. Keywords: groundwater, ultrafiltrati<strong>on</strong>. 106
Abstracts 15) 40089 – Sorpti<strong>on</strong> Behavior of Iodine <strong>on</strong> Calcium Silicate Hydrates Formed as a Sec<strong>on</strong>dary Mineral Keisuke Shirai, Yuichi Niibori, Akira Kirishima, Hitoshi Mimura, Tohoku Univ. (Japan) This study examined the sorpti<strong>on</strong> behaviors of iodine into CSH gel without dried processes, c<strong>on</strong>sidering the repository system saturated with groundwater after the backfilling. In glove box saturated with N2 gas, each sample of CSH gel was synthesized with CaO, SiO2, and distilled water with liquid/solid ratio 20. <str<strong>on</strong>g>The</str<strong>on</strong>g>n, 1 mM iodine soluti<strong>on</strong> is added into the aqueous soluti<strong>on</strong> including the CSH gel with various Ca/Si molar ratios under the isothermal c<strong>on</strong>diti<strong>on</strong> (298 K). In the results, even if the Ca/Si ratio is relatively small (
Change language