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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