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Journal Articles

Applicability of the PHITS code to a tokamak fusion device

Sukegawa, Atsuhiko; Okuno, Koichi*; Kawasaki, Hiromitsu*

RIST News, (51), p.20 - 29, 2011/07

no abstracts in English

JAEA Reports

Study on the effects of long-term evolution of geological environment on groundwater flow (Contract research)

Imai, Hisashi*; Yamashita, Ryo*; Shiozaki, Isao*; Urano, Kazuhiko*; Kasa, Hiroyoshi*; Maruyama, Yoshio*; Niizato, Tadafumi; Maekawa, Keisuke

JAEA-Research 2009-001, 116 Pages, 2009/03

JAEA-Research-2009-001.pdf:32.12MB

Evaluation of long-term geological evolution and its impact on groundwater flow is one of the major themes within the frame of Horonobe Underground Research Laboratory Project. For the purpose of development of a groundwater flow modeling methodology considering the effects of long-term geological evolution, following three items were studied: (1) Upgrade of SMS (Sequential Modeling System of geo-environmental evolution impact on groundwater flow) which was developed in 2006 FY; (2) Groundwater flow simulation under more realistic conditions of geological structures and hydrogeological conditions; and (3) Sensitivity study of geo-environmental evolution impacts on groundwater flow. The studies showed following suggestive results. (1) Development of a precise time step setting enabled to narrow the gaps in simulated head between time steps in which the model configuration used to deformed. (2) Several aspects have been found from studies on impact factors such as deposition on pore pressure, recharge rate and difference in density of saline groundwater. For evaluation of pore pressure induced by deposition, it is necessary to model the porosity and permeability variation considering the exceed pore pressure change. The setting of recharge rate during the Ice Age influence the characteristics of groundwater flow in coastal and hilly areas. The density of groundwater is not so influential as topological potential factors, however it is effective for the characteristics of groundwater flow in coastal area and intrusion of recharge water from ground surface. (3) The sensitivity study on faulting characteristics indicated that the two types of fault configuration and the hydraulic conductivity setting considered are not influential on the nature of groundwater flow above the depth of 500 m.

JAEA Reports

Investigation of sub-surface disposal concept; The Cases of Finland and Sweden (Contract research)

Koibuchi, Hiroto; Dohi, Terumi; Nakagoshi, Akio*; Amemiya, Kiyoshi*

JAEA-Review 2008-035, 21 Pages, 2009/02

JAEA-Review-2008-035.pdf:1.28MB

Sub-surface disposal is one of the disposal methods for low-level radioactive waste in Japan. It will operate below the generally used depth domestically. The waste disposed by this method is assumed to be core internals and part of TRU (the transuranium elements) waste from reprocessing and MOX (mix oxide fuel) fuel fabrication facilities. These contain the waste generated as a result of research activities, too. In order to establish a safety regulation for the disposal, a case study of the overseas disposal is useful. The similar disposal plan of Japan has been considered or already operated especially in Finland and Sweden. Therefore, in this study, we investigated current status and concept of appropriate sub-surface disposal in both countries as below. In Finland, waste management and disposal methods are regulated by Nuclear Energy Act and national policy. Low and intermediate level wastes are disposed into the cave in bedrock at each nuclear power plant site. In Sweden, safety handling and disposal of waste are regulated by Act on Nuclear Activities. The disposal of low and intermediate level wastes has been operated under the seabed. This operation is carried out by a joint company which the nuclear companies have formed. In addition, we reported a site selection, burial depth and financial plan etc. in both nations.

JAEA Reports

Study on the Monitoring Methods for Engineered Barriers Performance Confirmation (II)

Chijimatsu, Masakazu*; Fukudome, Kazuto*; Urano, Kazuhiko*; Imai, Hisashi*; Sasaki, Hajime*; Amemiya, Kiyoshi*

JNC-TJ8400 2004-027, 87 Pages, 2005/02

JNC-TJ8400-2004-027.pdf:2.13MB

This study investigates the methodology for the engineered barriers performance confirmation. First of all the investigation about the monitoring concept in foreign countries were performed and the monitoring aiming was fixed at the performance confirmation of the engineered barriers. The monitoring item and the element of engineered barriers were set as followings, namely temperature, hydraulic pressure, water contents, pH, Eh and the chemistry of solutions. The indirect measuring method of items both providing the engineered barriers performance and varying with exhibition of performance from the rock around the engineered barriers is proposed for the engineered barriers performance confirmation monitoring.

JAEA Reports

Investigation Research on the Evaluation of a Coupled Thermo-Hydro-Mechanical-Chemical Phenomena (IV) -Result Report-

Ishihara, Yoshinao*; Chijimatsu, Masakazu*; Amemiya, Kiyoshi*; Shiozaki, Isao*; Ito, Takaya*

JNC-TJ8400 2004-015, 192 Pages, 2005/02

JNC-TJ8400-2004-015.pdf:1.98MB

In order to realize a coupling analysis in the near field of the geological disposal system, the coupling analysis code "COUPLYS (Coupling Analysis System)" on the Thermo-Hydro-Mechanical-Chemical (THMC) phenomena by THAMES, Dtransu and phreeqc, which are existing analysis code, is developed in this study.

JAEA Reports

Renewal of the existing hydrogeological model and groundwater flow simulation

Imai, Hisashi*; Shiozaki, Isao*

JNC-TJ5440 2004-001, 80 Pages, 2004/11

JNC-TJ5440-2004-001.pdf:34.21MB

To understand the deep underground geological environment around the Horonobe Underground Research Laboratory, and to estimate the underground facility construction effect on the geological environment, renewal of the existing hydrogeological model and groundwater flow simulations were carried out.

JAEA Reports

Investigation Research on the Evaluation of a Coupled Thermo-Hydro-Mechanical-Chemical Phenomena (III) -Result Report-

Ishihara, Yoshinao*; Chijimatsu, Masakazu*; Amemiya, Kiyoshi*; Shiozaki, Isao*; Ito, Takaya*

JNC-TJ8400 2004-004, 625 Pages, 2004/02

JNC-TJ8400-2004-004.pdf:7.37MB

In order to realize a coupling analysis in the near field of the geological disposal system, the coupling analysis code on the thermo-hydro-mechanical-chemical phenomena by THAMES, Dtransu and phreeqc, which are existing analysis code, is developed in this study. And we carried out the case analysis on the thermo-hydro-mechanical-chemical phenomena by this code.(1).Some supporting module, which includes transfer of dissolution concentration and total concentration (dissolution + precipitation concentration), was prepared as a functional expansion. And in order to treat de-gases and gases diffusion, accumulation and dilution phenomena, we have modified mass transport analysis code.(2).We have modified reactive transport module to treat ionic exchange, surface reaction and kinetic reaction in the each barrier.(3).We have prepared hydraulic conductivity module of buffer material depending on change of dry density due to chemical equilibrium (dissolution and precipitation of minerals), degradation of buffer material such as Ca-type bentonite and change of concentration of NaCl solutions. After THAMES, Dtransu, phreeqc and hydraulic conductivity module were installed in the COUPLYS, verification study was carried out to check basic function. And we have modified COUPLYS to control coupling process.(4).In order to confirm the applicability of the developed THMC analysis code, we have carried out case analysis on 1-dimensional and 3-dimensional model which including vitrified waste, over-pack, buffer material and rock in the HLW near-field.

JAEA Reports

Study on the Monitoring Methods for Engineered Barriers Performance Confirmation

Chijimatsu, Masakazu*; Imai, Hisashi*; Sasaki, Hajime*; Moro, Yoshiji*

JNC-TJ8400 2003-090, 116 Pages, 2004/02

JNC-TJ8400-2003-090.pdf:3.43MB

This study investigates the methodology for the engineered barriers performance confirmation. First of all the investigation about the monitoring concept in foreign countries were performed and the monitoring aiming was fixed at the performance confirmation of the engineered barriers. The monitoring item and the element of engineered barriers were set as followings, namely temperature, hydraulic pressure, water contents, pH, Eh and the chemistry of solutions. The indirect measuring method of items both providing the engineered barriers performance and varying with exhibition of performance from the rock around the engineered barriers is proposed for the engineered barriers performance confirmation monitoring. Finally the problems to be solved for the future monitoring program are clarified, and the plan of R&D for sensing methods in the performance assessment, and the in-situ experimental plan in the Horonobe deep underground research center are proposed.

JAEA Reports

Research on Evaluation of Coupled Thermo-Hydro-Mechanical Phenomena in the Near-Field

Chijimatsu, Masakazu*; Imai, Hisashi*; Fukudome, Kazuto*; Kayukawa, Koji*; Sasaki, Hajime*; Moro, Yoshiji*

JNC-TJ8400 2003-089, 354 Pages, 2004/02

JNC-TJ8400-2003-089.pdf:17.22MB

After emplacement of the engineered barrier system (EBS), it is expected that the near-field environment will be impacted by phenomena such as heat dissipation by conduction and other heat transfer mechanisms, infiltration of groundwater from the surrounding rock in to the engineered barrier system, stress imposed by the overburden pressure and generation of swelling pressure in the buffer due to water infiltration. In order to recognize and evaluate these coupled thermo-hydro-mechanical (THM) phenomena, it is necessary to make a confidence of the mathematical models and computer codes. Evaluating these coupled THM phenomena is important in order to clarify the initial transient behavior of the EBS within the near field. DECOVALEX project is an international co-operative project for the DEvelopment of COupled models and their VALidation against EXperiments in nuclear waste isolation and it is significance to participate this project and to apply the code for the validation. Therefore, we tried to apply the developed numerical code against the subjects of DECOVALEX. We carried out the simulation against the Task1 (simulation of FEBEX in-situ full-scale experiment), Task 3 BMT1 (Bench Mark Test against the near field coupling phenomena) and Task3 BMT2 (Bench Mark Test against the up-scaling of fractured rock mass). This report shows the simulation results against these tasks. Furthermore, technical investigations about the in-situ full-scale experiment (called Prototype Repository Project) in Aspo HRL facility by SKB of Sweden were performed. In order to evaluate the coupled phenomena in the engineered barrier, we use the new swelling model based on the theoretical approach. In this paper, we introduce the modeling approach and applicability about the new model.

JAEA Reports

Study on Groundwater Flow Characteristics in Horonobe Underground Research Laboratory Project

Imai, Hisashi*; Fukudome, Kazuto*; Kayukawa, Koji*; Sasaki, Hajime*; Chijimatsu, Masakazu*; Moro, Yoshiji*

JNC-TJ5400 2003-009, 223 Pages, 2004/02

JNC-TJ5400-2003-009.pdf:59.94MB
JNC-TJ5400-2003-009(errata).pdf:0.08MB

In order to search for an appropriate methodology of the regional groundwater flowanalysis for sedimentary rock mass area, the following four studies were carried out: 1) Two simulation region setting and data set arrangement of the two region for numerical simulation of groundwater flow 2) Evaluation of regional groundwater flow characteristics in the Horonobe Project site using the results of the numerical simulation and obtained field data 3) Estimation of the shaft excavation effect on the groundwater flow such as the inflow rate of groundwater into the shafts, the chroline contents of groundwater flowing into the shafts and the hydraulic head evolution around the shafts 4) Proposal of desirable investigations for the next stage : the methodology of evaluating groundwater flow characteristics

JAEA Reports

Groundwater flow analysis for validity evaluation of analytical code

Hazama Corporation*

JNC-TJ7440 2005-079, 70 Pages, 2003/07

JNC-TJ7440-2005-079.PDF:1.99MB

This report is the one that the result of executing the underground water flow analysis intended for the exercise obtained from document information etc. aiming to extract the problem in the current state for the underground water flow analysis was arranged.

JAEA Reports

Investigation Research on the Evaluation of a Coupled Thermo-Hydro-Mechanical-Chemical Phenomena (II); Outline Report

Ishihara, Yoshinao*; Chijimatsu, Masakazu*; Neyama, Atsushi*; Tanaka, Yumiko*; Amemiya, Kiyoshi*; Shiozaki, Isao*; Ito, Takaya*

JNC-TJ8400 2003-033, 118 Pages, 2003/02

JNC-TJ8400-2003-033.pdf:1.66MB

In order to realize a coupling analysis in the near field of the geological disposal system, the coupling analysis code on the thermo-hydro-mechanical-chemical phenomena by THAMES, Dtransu and phreeqe60, which are existing analysis code, is developed in this study. And we carried out the case analysis on the thermo-hydro-mechanical-chemical phenomena by this code.

JAEA Reports

Investigation Research on the Evaluation of a Coupled Thermo-Hydro-Mechanical-Chemical Phenomena (II) - Result Report-

Ishihara, Yoshinao*; Chijimatsu, Masakazu*; Neyama, Atsushi*; Tanaka, Yumiko*; Amemiya, Kiyoshi*; Shiozaki, Isao*; Ito, Takaya*

JNC-TJ8400 2003-032, 237 Pages, 2003/02

JNC-TJ8400-2003-032.pdf:2.5MB

In order to realize a coupling analysis in the near field of the geological disposal system, the coupling analysis code on the thermo-hydro-mechanical-chemical phenomena by THAMES, Dtransu and phreeqe60, which are existing analysis code, is developed in this study. And we carried out the case analysis on the thermo-hydro-mechanical-chemical phenomena by this code.

JAEA Reports

Prediction Analysis of Fracture Propagation and Initiation during excavation of Research Tunnels

Moro, Yoshiji*; Amemiya, Kiyoshi*

JNC-TJ7400 2005-051, 171 Pages, 2003/02

JNC-TJ7400-2005-051.pdf:13.35MB

In this report, the excavation influence analysis was executed imitating MIU by using crack progress analysis code FRACOD.

JAEA Reports

Research on Evaluation of Coupled Thermo-Hydro-Mechanical Phenomena against Full-scale In-situ Engineered Barrier Experiment

Chijimatsu, Masakazu*; Amemiya, Kiyoshi*

JNC-TJ8400 2003-020, 53 Pages, 2003/01

JNC-TJ8400-2003-020.pdf:1.02MB

In order to achieve the geological disposal of radioactive waste in safe, it is necessary to ensure the stability of the engineered barrier system (EBS). One of the most important factors for the stability of the EBS is the emplacement technology of the EBS. It is considered that the stability of the EBS is secured by the properly emplacement based on the design requirement. In this research, the methods filling the gap between buffer and rock or buffer and over-pack were examined. Bentonite pellets were tested as the filling materials. To research the time-dependent phenomena of bentonite pellets after swelling, permeability tests were conducted with different period. Furthermore, to clarify the effect of test fluid, permeability test was conducted with synthetic seawater to compare the result with that of the test with distilled water. After emplacement of the engineered barrier system, it is expected that the near-field environment will be impacted by phenomena such as heat dissipation by conduction and other heat transfer mechanisms, infiltration of groundwater from the surrounding rock in to the engineered barrier system, stress imposed by the overburden pressure and generation of swelling pressure in the buffer due to water infiltration. In order to recognize and evaluate these coupled phenomena, it is necessary to make a confidence of the mathematical models and computer codes based on the information about the in-situ experiments regarding the engineered barrier system. In this research, technical investigations about the in-situ full-scale experiment (called Prototype Repository Project) in Aspo HRL facility by SKB of Sweden were performed. In order to evaluate the coupled phenomena in the engineered barrier, we use the new swelling model based on the theoretical approach. In this paper, we introduce the modeling approach and applicability about the new model.

JAEA Reports

Research on Evaluation of Coupled Thermo-Hydro-Mechanical Phenomena against Full-scale In-situ Engineered Barrier Experiment

Chijimatsu, Masakazu*; Amemiya, Kiyoshi*

JNC-TJ8400 2003-019, 202 Pages, 2003/01

JNC-TJ8400-2003-019.pdf:4.56MB

In order to achieve the geological disposal of radioactive waste in safe, it is necessary to ensure the stability of the engineered barrier system (EBS). One of the most important factors for the stability of the EBS is the emplacement technology of the EBS. It is considered that the stability of the EBS is secured by the properly emplacement based on the design requirement. In this research, the methods filling the gap between buffer and rock or buffer and over-pack were examined. Bentonite pellets were tested as the filling materials. To research the time-dependent phenomena of bentonite pellets after swelling, permeability tests were conducted with different period. Furthermore, to clarify the effect of test fluid, permeability test was conducted with synthetic seawater to compare the result with that of the test with distilled water. After emplacement of the engineered barrier system, it is expected that the near-field environment will be impacted by phenomena such as heat dissipation by conduction and other heat transfer mechanisms, infiltration of groundwater from the surrounding rock in to the engineered barrier system, stress imposed by the overburden pressure and generation of swelling pressure in the buffer due to water infiltration. In order to recognize and evaluate these coupled phenomena, it is necessary to make a confidence of the mathematical models and computer codes based on the information about the in-situ experiments regarding the engineered barrier system. In this research, technical investigations about the in-situ full-scale experiment (called Prototype Repository Project) in Aspo HRL facility by SKB of Sweden were performed. In order to evaluate the coupled phenomena in the engineered barrier, we use the new swelling model based on the theoretical approach. In this paper, we introduce the modeling approach and applicability about the new model.

JAEA Reports

Research on simulation against the DECOVALEX project; Document prepared by other institute, based on the contract

Chijimatsu, Masakazu*; Amemiya, Kiyoshi*

JNC-TJ8400 2003-010, 190 Pages, 2003/01

JNC-TJ8400-2003-010.pdf:26.58MB

After emplacement of the engineered barrier system (EBS), it is expected that the near-field environment will be impacted by phenomena such as heat dissipation by conduction and other heat transfer mechanisms, infiltration of groundwater from the surrounding rock in to the engineered barrier system, stress imposed by the overburden pressure and generation of swelling pressure in the buffer due to water infiltration. In order to recognize and evaluate these coupled thermo-hydro-mechanical (THM) phenomena, it is necessary to make a confidence of the mathematical models and computer codes. Evaluating these coupled THM phenomena is important in order to clarify the initial transient behavior of the EBS within the near field. DECOVALEX project is an international co-operative project for the DEvelopment of COupled models and their VALidation against Experiments in nuclear waste isolation and it is significance to participate this project and to apply the code for the validation. Therefore, we tried to apply the developed numerical code against the subjects of DECOVALEX. We carried out the simulation against the Task1 (simulation of FEBEX in-situ full-scale experiment), Task 3 BMT1 (Bench Mark Test against the near field coupling phenomena) and Task3 BMT2 (Bench Mark Test against the up-scaling of fractured rock mass). This report shows the simulation results against these tasks.

JAEA Reports

Study on regionary groundwater flow analysis relevant to the Horonobe underground research program

Imai, Hisashi*; *; Yamashita, Ryo*; *; Amemiya, Kiyoshi*; Chijimatsu, Masakazu*

JNC-TJ1400 2002-004, 357 Pages, 2002/03

JNC-TJ1400-2002-004.pdf:25.69MB

JAEA Reports

Research on evaluation of coupled thermo-hydro-mechanical phenomena against full-scale in-situ experiment

Chijimatsu, Masakazu*; Amemiya, Kiyoshi*; Yamashita, Ryo*

JNC-TJ8400 2002-024, 53 Pages, 2002/02

JNC-TJ8400-2002-024.pdf:4.81MB

no abstracts in English

JAEA Reports

Research on evaluation of coupled thermo-hydro-mechanical phenomena against full-scale in-situ experiment

Chijimatsu, Masakazu*; Amemiya, Kiyoshi*; Yamashita, Ryo*

JNC-TJ8400 2002-023, 147 Pages, 2002/02

JNC-TJ8400-2002-023.pdf:10.91MB

In order to achieve the geological disposal of radioactive waste in safe, it is necessary to ensure the stability of the engineered barrier system (EBS). One of the most important factors for the stability of the EBS is the emplacement technology of the EBS. It is considered that the stability of the EBS is secured by the property emplacement based on the design requirement. In this research, the methods filling the gap between buffer and rock or buffer and over-pack were examined. Bentonite pellets were tested as the filling materials. To research the time-dependent phenomena of bentonite pellets after swelling, permeability tests were conducted with different period. Furthermore, to clarify the effect of test fluid, permeability test was conducted with synthetic seawater to compare the result with that of the test with distilled water. After emplacement of the engineered barrier system, it is expected that the near-field envilonment will be impacted by phenomena such as heat dissipation by conduction and other heat transfer mechanisms, infiltration of groundwater from the surrounding rock in to the engineered barrier system, stress imposed by the overburden pressure and generation of swelling pressure in the buffer due to water infiltration. In order to recognize and evaluate these coupled phenomena, it is necessary to make a confidence of the mathematical models and computer codes based on the information about the in-situ experiments regarding the engineered barrier system. In this research, technical investigations about the in-situ full-scale experiment (called Prototype Repository Project) in Aspo HRL facility by SKB of Sweden were performed.

62 (Records 1-20 displayed on this page)