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Takai, Shizuka; Kimura, Hideo*; Uchikoshi, Emiko*; Munakata, Masahiro; Takeda, Seiji
JAEA-Data/Code 2020-007, 174 Pages, 2020/09
JAEA-Data-Code-2020-007.pdf:4.23MB
The MIG2DF computer code is a computer program that simulates groundwater flow and radionuclide transport in porous media for the safety assessment of radioactive waste disposal. The original version of MIG2DF was released in 1992. The original code employs a two-dimensional (vertical or horizontal cross-section, or an axisymmetric configuration) finite-element method to approximate the governing equations for density-dependent saturated-unsaturated groundwater flow and radionuclide transport. Meanwhile, for geological disposal of radioactive wastes, landscape evolution such as uplift and erosion needs to be assessed as a long-term geological and climate events, considering site conditions. In coastal areas, the impact to groundwater flow by change of salinity distribution to sea level change also needs to be considered. To deal with these events in the assessment, we have revised the original version of MIG2DF and developed the external program which enables MIG2DF to consider unsteady landscape evolution. In these developments, this report describes an upgrade of MIG2DF (Version 2) and presents the configuration, equations, methods, and verification. This reports also give the explanation external programs of MIG2DF: PASS-TRAC (the particle tracking code), PASS-PRE (the code for dataset preparation), and PASS-POST (the post-processing visualization system).
Shimada, Taro; Takeda, Seiji; Mukai, Masayuki; Munakata, Masahiro; Tanaka, Tadao
Materials Research Society Symposium Proceedings, Vol.1744, p.229 - 234, 2015/04
Integrated safety assessment methodology which analyzes radionuclide migration reflecting the spatial and temporal changes of disposal systems was developed for a geological disposal site with uplift and denudation, and then some case analyses for an assumed site with sedimentary rocks were carried out. The combination of uniform uplift and denudation has the most effect on the radionuclide migration because the groundwater flow velocity increases with decreasing the depth from the ground surface. In the case without denudation, tilted uplift has more effect than uniform uplift because flow velocity in tilted uplift increase with increasing hydraulic gradient. The long-term change of the geological structures including the uplift and denudation, the hydraulic conditions, and the recharge and outlet of the groundwater around a candidate site should be carefully investigated to determine the appropriate the place,depth and layout of the repository.
Saito, Kimiaki; Onda, Yuichi*
Journal of Environmental Radioactivity, 139, p.240 - 249, 2015/01
Times Cited Count：52 Percentile：92.66(Environmental Sciences)no abstracts in English
In, Teiji*; Shima, Shigeki*; Nakayama, Tomoharu*; Ishikawa, Yoichi*; Togawa, Orihiko; Kobayashi, Takuya; Kawamura, Hideyuki
Gekkan Kaiyo, 37(9), p.674 - 680, 2005/09
no abstracts in English
Yamaguchi, Tetsuji; Negishi, Kumi; Ebashi, Katsuhiro; Inagaki, Shingo*; Shibata, Mitsunobu*; Tanaka, Tadao; Nakayama, Shinichi
JAERI-Conf 2004-011, p.139 - 140, 2004/07
Uncertainties should be quantitatively assessed in a long-term assessment of radioactive waste disposal. We focus our experimental efforts on parameters that induce major uncertainties in the radionuclide migration analysis and that have not been quantitatively understood. Solubility of radionuclides, diffusion in bentonite buffer material and sorption on rocks were investigated to quantify the uncertainties associated with the parameters and to minimize the uncertainties.
Umeki, Hiroyuki*; Kimura, Hideo
Nihon Genshiryoku Gakkai-Shi, 46(1), p.38 - 51, 2004/01
Radioactive waste disposals are performed by passive systems will not depend on the direct human actions. Geologic disposal is a methodology isolate long-lived radioactive wastes such as high-level radioactive waste from human and his environment safely. This paper describes safety assessment of geologic disposal.
Yamaguchi, Tetsuji; Nakayama, Shinichi
JAERI-Conf 2003-018, p.115 - 116, 2003/10
Effective diffusivity was determined for Np(IV) in bentonite material in presence of carbonate and for Pu(IV) in presence of fulvic acid. Adsorption of actinides onto negatively charged mineral surfaces were investigated under conditions that actinides were predominantly present as anionic complex species. The results of this study will reveal behavior of actinides under various geological environments.
Tanaka, Tadao; Mukai, Masayuki; Munakata, Masahiro; Maeda, Toshikatsu; Ogawa, Hiromichi; Wang, Z.*; Li, S.*; Yang, Y.*; Zhao, Y.*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 2(3), p.350 - 360, 2003/09
Migration data of 
Sr,
Np and 
Pu in natural aquifer were collected by a field test, which was performed in an aquifer at 30 m under ground surface of the field test site. Migration parameters for analysis of the results obtained the field test were measured by laboratory column tests and batch tests. Diffusion coefficient corresponding to water velocity was determined from the relationship between water velocity and diffusion length, which obtained from the column tests. Distribution coefficient was determined by considering confident ability of data, test conditions, and environmental conditions. One dimensional migration behavior of the radionuclides in aquifer, calculated by using the migration parameters obtained from the batch and column tests, agreed with the results obtained from the field test. It was confirmed that the migration behavior of alpha-nuclides could be evaluated by applying the conventional equation for evaluating the radionuclide migration and the migration parameters obtained from laboratory tests.
Mukai, Masayuki; Tanaka, Tadao; Maeda, Toshikatsu; Ogawa, Hiromichi; Matsumoto, Junko; Munakata, Masahiro; Zhao, Y.*; Guo, Z.*; Ni, S.*; Li, S.*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 2(3), p.342 - 349, 2003/09
Evaluation of radionuclide migration in geologic media is of great importance in safety assessment for shallow land disposal specially for TRU nuclides because of inadequate data based on field test. As a cooperative research between JAERI and CIRP, a field test of radionuclide migration was conducted under natural condition using Sr-90, Np-237 and Pu-238 to obtain migration data of the radionuclides in actual aerated layer under natural rainfall condition. Values of input parameters to an existing evaluation equation of nuclide migration were determined on the basis of the results of laboratory experiments of batch and column methods and field investigation. Migration distribution of the radionuclides calculated with the determined values showed reasonable agreement with the measured distribution of the field test. This confirmed an applicability of the evaluation equation for radionuclide migration to actual aerated layer under natural condition.
Munakata, Masahiro; Kimura, Hideo; Tanaka, Tadao; Mukai, Masayuki; Maeda, Toshikatsu; Ogawa, Hiromichi
Nihon Genshiryoku Gakkai Wabun Rombunshi, 2(3), p.361 - 367, 2003/09
no abstracts in English
Tanaka, Tadao; Mukai, Masayuki; Maeda, Toshikatsu; Munakata, Masahiro; Matsumoto, Junko; Ogawa, Hiromichi; Bamba, Tsunetaka*; Wang, Z.*; Yang, Y.*; Zhao, Y.*
Proceedings of International Symposium on Radioecology and Environmental Dosimetry, p.179 - 184, 2003/00
Migration behaviors of stable strontium element and radioactive nuclide strontium 90 in natural aquifer were studied by a field test, which was performed in the aquifer loess zone at 30 m under the ground surface of the field test site of China Institute for Radiation Protection. The migration behavior of stable strontium was a little different from that of Sr. The difference was evaluated by applying the distribution coefficient considering Sr and coexistent ion concentrations. Migration behavior of radionuclide in natural environment has been generally demonstrated on field tests without radioactive tracers and/or large-scale column tests with radioactive tracers. Such tests seem to be valuable to improve reliability of the migratory evaluation.
Nakashio, Nobuyuki; Nakashima, Mikio
Dekomisshoningu Giho, (26), p.45 - 55, 2002/11
Melting treatment of low-level radioactive wastes (LLW) is considered to be a promising technology for the preparation of a stable solid that will be disposed of in near surface repositories. This is because of large reduction of waste volume and production of a stable homogeneous solidified product. In the Japan Atomic Energy Research Institute (JAERI), the construction of the Waste Volume Reduction Facilities (WVRF) has been in progress since 1999. In advance of operation of the WVRF, we have been conducting melting tests of non-metallic solid wastes with the aim of establishing the optimum melting condition for preparation of a stable solid that is suitable for disposal. We have reviewed a part of the melting test conducted in our program.
Kakiuchi, Hideki; Amano, Hikaru; Ichimasa, Michiko*
Journal of Radioanalytical and Nuclear Chemistry, 252(2), p.437 - 439, 2002/05
Times Cited Count：6 Percentile：39.54(Chemistry, Analytical)no abstracts in English
Sato, Haruo
JNC TN1200 2001-007, 38 Pages, 2002/03
JNC-TN1200-2001-007.pdf:8.64MB
no abstracts in English
*;
JNC TN8400 2001-027, 131 Pages, 2001/11
In order to document a basic manual about input data, output data, execution of computer code on groundwater flow and radionuclide transport calculation in heterogeneous porous rock, we investigated the theoretical background about geostastical computer codes and the user's manual for the computer code on groundwater flow and radionuclide transport which calculates water flow in three dimension, the path of moving radionuclide, and one dimensional radionuclide migration. In this report, based on above investigation we describe the geostastical background about simulating heterogeneous permeability field. And we describe construction of files, input and output data, a example of calculating of the programs which simulates heterogeneous permeability field, and calculates groundwater flow and radionuclide transport. Therefore, we can document a manual by investigating the theoretical background about geostastical computer codes and the user's manual for the computer code on groundwater flow and radionuclide transport calculation. And we can model heterogeneous porous rock and analyze groundwater flow and radionuclide transport by utilizing the information from this report.
*
JNC TN1400 2001-013, 70 Pages, 2001/08
JNC-TN1400-2001-013.pdf:5.13MB
no abstracts in English
*; Kanazawa, Yasuo*;
JNC TN8400 2001-012, 69 Pages, 2001/04
JNC-TN8400-2001-012.pdf:6.87MB
On understanding the radionuclide transport in natural barrier in radioactive waste isolation research, the macroscopic dispersion in heterogeneous permeability field in the underground rock is regarded as an important process. Therefore, we have conducted lots of tracer experiments by the MACRO II facility with an artificially constructed heterogeneous permeability field. In order to study the scale dependence of dispersion coefficients in case of laboratory experiments, we placed the flow cell horizontally, and conducted injection-withdraw tracer experiment with a single well. We have conducted I5 cases experiments. These cases were prepared by changing a position of single well and the injection-withdraw time. At each position we have conducted 9 cases and 6 cases experiments. In this report, we evaluated the macroscopic dispersion coefficients by the fitting of analytical solution to breakthrough curve measured by the 15 cases pumping tracer experiment. Consequently, we could evaluate the dispersion coefficients for 12 cases of 15 cases. Then, we discussed the relation between a injection-withdraw flow rate and a property of heterogeneous media and dispersion coefficient. The conclusions obtained from the results of the evaluation are summarized as follows, (1)It was found that the macroscopic dispersion coefficients tend to be increased with increase of the average radius of tracer front spread around a single well. (2)We have conducted any experiments with s single well settled at two positions. In case of that there is low permeability around a single well, we found dispersion coefficients are large. In case of that there is high permeability around a single well, we found dispersion coefficients are small. (3)In three cases that we could not evaluate because of incorrect accuracy of fitting, we have found it possible that there is some points that dispersion coefficients were strikingly small in tracer front.
; *
JNC TN8400 2001-010, 25 Pages, 2001/03
Performance assessment in geosphere for the JNC's 2nd progress report was based on nuclide migration calculation results by discrete fracture network model. The channel network model approximated from fracture network model with considering fracture connectivity was applied for nuclide migration analysis, since fracture network model had too large data to calculate nuclide migration. However, there are many options in the process of approximation from fracture network model to channel network model. In case of analyzing nuclide migration for above report, so-called "base case", one option was chosen from many options, arbitrarily. In this report, the sensitivity of these options to nuclide migration calculation results was studied. As a result, there was no significant impact to nuclide migration although connectivity of channel and flow characteristics of the model slightly changed among different options. Based on above studies, we concluded that an option used for the base case was appropriate.
Kimura, Hideo
KURRI-KR-56, p.95 - 108, 2001/03
no abstracts in English
Ogawa, Hiromichi; Nagao, Seiya; Yamaguchi, Tetsuji; Mukai, Masayuki; Munakata, Masahiro; Sakamoto, Yoshiaki; Nakayama, Shinichi; Takeda, Seiji; Kimura, Hideo; Kumata, Masahiro; et al.
JAERI-Research 2000-052, 101 Pages, 2001/01
JAERI-Research-2000-052.pdf:8.27MB
no abstracts in English
