Evaluation of excavation damaged zones (EDZs) in Horonobe Underground Research Laboratory (URL)

Hata, Koji*; Niunoya, Sumio*; Aoyagi, Kazuhei

International Journal of the JSRM (Internet), 20(1), p.240104_1 - 240104_4, 2024/11

https://doi.org/10.11187/ijjsrm.240104

Japan Atomic Energy Agency has been conducting R&D activities to enhance the reliability of high-level radioactive waste deep geological disposal technology. In this project, one of the challenges is the development of methods for long-term monitoring of rock mass behavior. Therefore, in January 2014, the long-term measurements of the hydro-mechanical behavior of the rock mass were launched using the three types of optical sensors in the vicinity of the shaft excavated deeper than 350 m at the Horonobe Underground Research Center. The measurement results show that Acoustic emission occur frequently up to 1.5 m from the wall during excavation. In addition, hydraulic conductivity increased by 2-4 orders of magnitude. Elastoplastic analysis revealed that the hydraulic behavior of the rock mass affected the pore pressure fluctuations and caused micro-fractures. Based on this, a conceptual model is developed to represent the excavation damaged zone, which contributes to the safe geological disposal of radioactive waste.

Evaluation of excavation damaged zones (EDZs) in Horonobe Underground Research Laboratory (URL)

Hata, Koji*; Niunoya, Sumio*; Aoyagi, Kazuhei; Miyara, Nobukatsu*

Journal of Rock Mechanics and Geotechnical Engineering, 16(2), p.365 - 378, 2024/02

https://doi.org/10.1016/j.jrmge.2023.05.010

Excavation of underground caverns, such as mountain tunnels and energy-storage caverns, may cause the damages to the surrounding rock as a result of the stress redistribution. In this influenced zone, new cracks and discontinuities are created or propagate in the rock mass. Therefore, it is effective to measure and evaluate the acoustic emission (AE) events generated by the rocks, which is a small elastic vibration, and permeability change. The authors have developed a long-term measurement device that incorporates an optical AE (O-AE) sensor, an optical pore pressure sensor, and an optical temperature sensor in a single multi-optical measurement probe (MOP). Japan Atomic Energy Agency has been conducting R&D activities to enhance the reliability of high-level radioactive waste (HLW) deep geological disposal technology. In a high-level radioactive disposal project, one of the challenges is the development of methods for long-term monitoring of rock mass behavior. Therefore, in January 2014, the long-term measurements of the hydro-mechanical behavior of the rock mass were launched using the developed MOP in the vicinity of 350 m below the surface at the Horonobe Underground Research Center. The measurement results show that AEs occur frequently up to 1.5 m from the wall during excavation. In addition, hydraulic conductivity increased by 2 to 4 orders of magnitude. Elastoplastic analysis revealed that the hydraulic behavior of the rock mass affected the pore pressure fluctuations and caused micro-fractures. Based on this, a conceptual model is developed to represent the excavation damaged zone (EDZ), which contributes to the safe geological disposal of radioactive waste.

Acoustic emission in ITER CS model coil and CS insert coil

Ninomiya, Akira*; Arai, Kazuaki*; Takano, Katsutoshi*; Nakajima, Hideo; Michael, P.*; Martovetsky, N.*; Takahashi, Yoshikazu; Kato, Takashi; Ishigooka, Takeshi*; Kaiho, Katsuyuki*; et al.

Teion Kogaku, 36(6), p.344 - 353, 2001/06

https://doi.org/10.2221/jcsj.36.344

no abstracts in English

Behavior of acoustic emission caused by microfracture in polycrystalline graphites

Ioka, Ikuo; ; Konishi, Takashi*

Carbon, 28(6), p.879 - 885, 1990/00

https://doi.org/10.1016/0008-6223(90)90336-W

no abstracts in English

Acoustic emission measuremeut on superconductiug coil for fusion

;

Teion Kogaku, 22(1), p.30 - 33, 1987/01

https://doi.org/10.2221/jcsj.22.30

no abstracts in English

Acoustic emission measurement of large scale at JAERI

; ; ; ; ;

Advances in Cryogenic Engineering, Vol.31, p.277 - 284, 1986/00

no abstracts in English

Detecting Acoustic Emission During Cyclic Crack Growth in Simulated BWR Environment

Nakajima, Hajime; ; Shindo, Masami; ; ;

JAERI-M 9037, 35 Pages, 1980/09

JAERI-M-9037.pdf:1.8MB

no abstracts in English

Challenges for LIBS analysis of nuclear fuel debris at FDNPS; Effect of sample temperature and laser ablation angle on optical emission and acoustic signals from laser-induced Zirconium plasma

Batsaikhan, M.

no journal, ,