Comparison of field data and numerical simulation of nitrate evolution in groundwater using the model of nitrate evolution

Abe, Toru*; Hirano, Fumio; Mihara, Morihiro; Honda, Akira

Genshiryoku Bakkuendo Kenkyu (CD-ROM), 27(1), p.3 - 11, 2020/06

https://doi.org/10.3327/jnuce.27.1_3

Degradation of TRU waste in a geological disposal facility may cause the formation of a nitrate plume. A Nitrate Evolution model due to mineral reactions, microbial activity, and metal corrosiON (NEON) has therefore been developed to evaluate the safety case for geological disposal of TRU waste. Small scale laboratory experiments can be reproduced satisfactorily, however, it is necessary to demonstrate the applicability of the NEON model on scales relevant to the geological disposal of TRU waste. In the current study, an industrial analogue of a nitrate plume from the pollution of groundwater from nitrate fertilizers used on Ikuchi Island, Japan was selected to test the applicability of the NEON model. Concentration profiles of nitrate ions in the groundwater were successfully reproduced over the hundreds of meters scale demonstrating the applicability of the NEON model in evaluating the chemical behavior of a nitrate plume derived from the geological disposal of TRU waste.

Carbon steel corrosion induced by microbial community in soil environment and its analysis

Hirano, Shinichi*; Nagaoka, Toru*; Ise, Kotaro; Amano, Yuki; Matsumoto, Norio*

Zairyo To Kankyo, 64(12), p.535 - 539, 2015/12

https://doi.org/10.3323/jcorr.64.535

To obtain the knowledge about the corrosion ability and its mechanism as a target the soil environment microorganisms, lake mud was cultured with metallic iron. As a result, corrosion of carbon steel was observed with sulfate reduction and methane producing activity in brackish medium with lactate as substrate. Inhibition test of SRB and MPA suggested that SRB plays a major role for this corrosion, and MPA enhanced corrosion activity by the coexistence of SRB.

Study of specific energy for evaluation of in situ rock mass properties (Joint research)

Hikima, Ryoichi*; Hirano, Toru*; Yamashita, Masayuki*; Ishiyama, Koji*; Tanno, Takeo*; Sanada, Hiroyuki; Sato, Toshinori

JAEA-Research 2013-040, 51 Pages, 2014/03

JAEA-Research-2013-040.pdf:6.86MB

For the research and development about high-level radioactive waste disposal, it is important to evaluate the mechanical stability of the excavation and the long-term behavior of in situ rock. However, from the limited information such as the bowling core before the excavation, it is difficult to evaluate the mechanical properties of in situ rock containing cracks. For this reason, evaluation of rock properties based on Specific Energy using mechanical data from an excavation machine is carried out. This report describes the results of the joint research carried out in FY 2010 to FY 2012.

Estimation of geological structure around underground tunnel based on cross-correlation analyses of random continuous signals from small scale core drilling

Soma, Nobukazu*; Oikawa, Yasuki*; Hirano, Toru*; Matsui, Hiroya; Asanuma, Hiroshi*

Butsuri Tansa, 66(2), p.69 - 83, 2013/04

We have studied a reflection imaging technique in which passive seismic signals from other construction activity such as drilling noise are used as a wave source in order to develop a low-cost measurement method inside underground gallery. In this paper, we show an application to data sets from Mizunami Underground Research Laboratory of Japan Atomic Energy Agency. The drilling was conducted with a main purpose of extraction rock core samples for rock mechanics research. The three-dimensional reflection imaging results and comparison with well observation are shown in this paper.

Mizunami Underground Research Laboratory Project; Rock mechanical investigations measurement of the rock strain and displacement during shaft excavation at the GL.-200m level of research galley

Hirano, Toru*; Seno, Yasuhiro*; Hikima, Ryoichi; Matsui, Hiroya

JAEA-Research 2011-019, 51 Pages, 2011/09

JAEA-Research-2011-019.pdf:2.93MB

In order to establish the scientific and technical basis for geological disposal of high-level radioactive waste, Japan Atomic Energy Agency (JAEA) is proceeding with the geoscientific research in the research galleries excavated at the Mizunami Underground Research Laboratory (MIU). One of the scientific and technical objective of this project is to understand the change of geological environment due to excavation of research galleries. The investigation described herein is the measurement of the rock strain / displacement while pre-excavation grouting or excavating of the shaft around the GL.-200m level research gallery.

Mizunami Underground Research Laboratory Project; Rock mechanical investigations annual report for fiscal year 2009

Tanno, Takeo; Hirano, Toru*; Matsui, Hiroya

JAEA-Research 2011-013, 59 Pages, 2011/06

JAEA-Research-2011-013.pdf:5.39MB

This report presents the following FY2009 activities undertaken to achieve the above goals. (1) Suitability of Laboratory Tests of Physical and Mechanical Properties on Waste Rock from Excavation of the Shaft, (2) Suitability of the Phase I Rock Mechanical Environment Model, (3) Preliminary Deformation Analysis of Rock Mass around the Underground Facilities, (4) Phenomenological Study on Crystalline Rock for Evaluating Long-term Behavior, (5) Theoretical Study on Crystalline Rock for Evaluating of Long-term Behavior, (6) Fundamental Study on Evaluation Methods of Excavation Distributed Zones. As the result of above 6 activities, suitability of laboratory test and Phase I Rock mechanical Environment Model are confirmed and also methods for EDZ estimation were specified by estimation of in situ stress with core and SWD (Seismic While Drilling).

Mizunami Underground Research Laboratory Project, Annual report for fiscal year 2009

Kunimaru, Takanori; Mikake, Shinichiro; Nishio, Kazuhisa; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Hayano, Akira; Takeuchi, Ryuji; Saegusa, Hiromitsu; Oyama, Takuya; Mizuno, Takashi; et al.

JAEA-Review 2011-007, 145 Pages, 2011/03

JAEA-Review-2011-007.pdf:16.51MB

Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) Project in crystalline rock environment in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). Geoscientific research and the MIU Project are planned in three overlapping phases; Surface-based Investigation Phase (Phase 1), Construction Phase (Phase 2) and Operation Phase (Phase 3). Currently, the project is under the Construction Phase. This document introduces the results of the research and development in fiscal year 2009, as a part of the Construction Phase based on the MIU Master Plan updated in 2002, (1) Investigation at the MIU Construction Site and the Shobasama Site, (2) Construction at the MIU Construction Site, (3) Research Collaboration, etc. The goals of the Phase 2 are to develop and revise the models of the geological environment using the investigation results obtained during excavation and determine and assess changes in the geological environment in response to excavation, to evaluate the effectiveness of engineering techniques used for construction, maintenance and management of underground facilities, to establish detailed investigation plans of Phase 3.

Study on mechanisms of strain variation at great depth

Horiuchi, Yasuharu; Hirano, Toru*; Ikeda, Koki; Matsui, Hiroya

Dai-40-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu (CD-ROM), p.242 - 247, 2011/01

Japan Atomic Energy Agency (JAEA) installed the intelligent type strain meters, at G.L-500m depth in pilot boreholes drilled from the 200m level in the ventilation and main shafts of the Mizunami Underground Research Laboratory (MIU). Strain variations due to several events including the excavation itself were monitored and analyzed. Monitoring results indicate that the intelligent type strain meter is able to measure very small fluctuations and detect rock deformation from blasting with 300m vertical separation from the measurement section. The strain meter can detect conditions in the rock mass such as differences in deformability.

Phenomenological study on crystalline rock for evaluating of long-term behavior (Contract research)

Okubo, Seisuke*; Hikima, Ryoichi; Hirano, Toru*; Matsui, Hiroya

JAEA-Research 2010-031, 45 Pages, 2010/10

JAEA-Research-2010-031.pdf:1.22MB

Rock shows time-dependent behavior such as creep/relaxation. With respect to high-level radioactive waste disposal, knowledge of the long-term mechanical stability of shafts and galleries excavated in rock are required, not only during construction and operation but also over a period of thousands of years after closure. Therefore, it is very important to understand the time-dependent behavior of rock for evaluating long-term mechanical stability. The purpose of this study is determining the mechanisms of time-dependent behavior of rock by the precise test, observation and measurement, to develop methods for evaluating long-term mechanical stability. In previous work, testing techniques have been established and basic evaluation methods were developed. Recently, some parameters needed for simulation of time-dependent behavior were determined at the Mizunami underground research facilities. However, we did not have enough data to check on the reliability of the evaluation method for these parameters. This report describes the results of the activities in fiscal year 2009. In Chapter 1, we provide an overview and the background to this study. In Chapter 2, the results of the long-term creep test on Tage tuff, started in fiscal year, 1997 are described. In Chapter 3, methods for obtaining parameters of the constitutive equation for rock are reviewed and summarized. The time dependent behavior of Toki granite and Inada granite (40-80 C) are also summarized based on data obtained prior to the previous fiscal year. In Chapter 4, the FEM analysis implemented with a generalized variable-compliance-type constitutive equation carried out to clarify the long-term behavior of Toki granite is described. Finally, based on the numerical analysis, an in situ testing method is proposed.

Study on mechanisms of strain variation at great depth (Joint research)

Horiuchi, Yasuharu; Hirano, Toru; Ikeda, Koki; Matsui, Hiroya

JAEA-Technology 2010-017, 122 Pages, 2010/07

JAEA-Technology-2010-017.pdf:35.17MB
JAEA-Technology-2010-017-appendix(CD-ROM).zip:28.63MB

Knowledge of strain variations at an excavation face is important for the prediction of rock bursts and for the application of the appropriate supplementary construction methods for excavation of shafts to great depths. JAEA installed the intelligent type strain meters, at G.L-500m depth in pilot boreholes drilled from the 200m level in the ventilation and main shafts of the Mizunami URL. Strain variations due to several events including the excavation itself were monitored and analyzed. Because of the breakdown of the monitoring system, the data is very short term. Nevertheless, it was possible to do some analysis for the study and important understanding derived from the analysis. Monitoring results indicate that the intelligent type strain meter is able to measure very small fluctuations and detect rock deformation from blasting with 300m vertical separation from the measurement section. The strain meter can detect conditions in the rock mass such as differences in deformability.