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2020 Vol.30, Issue 4 Preview Page

Original Article

An Introduction to the DECOVALEX-2019 Task G: EDZ Evolution – Reliability, Feasibility, and Significance of Measurements of Conductivity and Transmissivity of the Rock Mass

DECOVALEX-2019 Task G 소개: EDZ Evolution – 굴착손상영역 평가를 위한 수리전도도 및 투수량계수 측정의 신뢰도, 적합성 및 중요성

Saeha Kwon1
,
Ki-Bok Min2*
권 새하1
,
민 기복2*
1Ph.D Student, Department of Energy Systems Engineering, Seoul National University
2Professor, Department of Energy Systems Engineering, Seoul National University
1서울대학교 에너지시스템공학부 박사과정
2서울대학교 에너지시스템공학부 교수
* Corresponding Author
31 August 2020. pp. 306-319
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Abstract

Characterizations of Excavation Damage Zone (EDZ), which is hydro-mechanical degrading the host rock, are the important issues on the geological repository for the spent nuclear fuel. In the DECOVALEX 2019 project, Task G aimed to model the fractured rock numerically, describe the hydro-mechanical behavior of EDZ, and predict the change of the hydraulic factor during the lifetime of the geological repository. Task G prepared two-dimensional fractured rock model to compare the characteristics of each simulation tools in Work Package 1, validated the extended three-dimensional model using the TAS04 in-situ interference tests from Äspö Hard Rock Laboratory in Work Package 2, and applied the thermal and glacial loads to monitor the long-term hydro-mechanical response on the fractured rock in Work Package 3. Each modelling team adopted both Finite Element Method (FEM) and Discrete Element Method (DEM) to simulate the hydro-mechanical behavior of the fracture rock, and added the various approaches to describe the EDZ and fracture geometry which are appropriate to each simulation method. Therefore, this research can introduce a variety of numerical approaches and considerations to model the geological repository for the spent nuclear fuel in the crystalline fractured rock.

Keywords
Geological repository
Spent nuclear fuel
Excavation Damage Zone
Numerical simulation
Fractured rock

사용후핵연료의 심층처분 사업에서는 처분장 주변 모암의 수리역학적 성능을 저하시키는 굴착손상영역의 특성화가 중요하다. 이에 DECOVALEX-2019 프로젝트의 Task G에서는 균열암반 수치해석 모델을 구축한 후 암반 주변의 굴착손상영역의 수리역학적 거동을 모사하고, 구축한 모델로 처분장의 운영 시에 장기적으로 야기될 수 있는 추가적인 수리학적 변화를 관찰하였다. 과업의 첫 번째 단계에서는 2차원 균열암반 모델을 구축하여 수치해석 기법의 특성을 파악하고, 두 번째 단계에서는 3차원 균열암반 모델로 확장 후 스웨덴 애스푀 지하연구시설(Äspö Hard Rock Laboratory) 내 TAS04 간섭시험 결과와 비교하여 수치해석 모델을 검증한 후, 세 번째 단계에서는 열과 빙하 하중에 의한 영향을 반영하여 균열암반의 수리역학적 반응을 순차적으로 확인하였다. 과업의 전 과정에서 유한요소법과 개별요소법으로 균열암반에서의 수리역학적 분석을 수행하였으며, 균열의 기하학적 특성을 반영 및 굴착손상영역을 반영하는 과정에서 각 수치해석 기법에 따라 다양한 접근방법으로 고려하였다. 따라서 본 연구는 향후 결정질 균열암반에 사용후핵연료 처분장을 계획할 시 수치해석 단계에서 채택될 수 있는 다양한 접근 방법과 고려해야 할 사항들을 제시할 수 있을 것으로 전망한다.

키워드
심층처분
사용후핵연료
굴착손상영역
수치해석
균열암반
References
1
Birkholzer J.T., C.F. Tsang, A.E. Bond, J.A. Hudson, L. Jing and O. Stephansson, 2019, 25 years of DECOVALEX - Scientific advances and lessons learned from an international research collaboration in coupled subsurface processes, Int. J. Rock Mech. Min. Sci. 122, 103995.
10.1016/j.ijrmms.2019.03.015
2
Christiansson R. and T. Janson, 2003, A test of different stress measurement methods in two orthogonal bore holes in Äspö Hard Rock Laboratory (HRL), Sweden. Int. J. Rock Mech. Min. Sci. 40(7-8), 1161-1172.
10.1016/j.ijrmms.2003.07.006
3
COMSOL Inc., 2018, COMSOL Multiphysics Reference Manual, COMSOL Inc.
4
Ericsson, L.O., J. Thörn, R. Christiansson, T. Lehtimäki, H. Ittner, K. Hansson, C. Burtron, O. Sigurdsson and P. Kinnbom, 2015, A Demonstration project on controlling and verifying the excavation-damaged zone. SKB R-14-30, Swedish Nuclear Fuel and Waste Management Co (SKB).
5
Hökmark, H., M. Lönnqvist and B. Fälth. 2010, THM-issues in repository rock, SKB TR-10-23, Swedish Nuclear Fuel and Waste Management Co (SKB).
6
Hudson, J.A., A. Bäckström, J. Rutqvist, L. Jing, T. Backers, M. Chijimatsu, R. Christiansson, X.T. Feng, A. Kobayashi, T. Koyama, H.S. Lee, I. Neretnieks, P.Z. Pan, M. Rinne and B.T. Shen, 2009, Characterising and modelling the excavation damaged zone in crystalline rock in the context of radioactive waste disposal, Environ. Geol. 57(6), 1275-1297.
10.1007/s00254-008-1554-z
7
Hwang, Y., 1997, Overview of the International DECOVALEX Project, Tunn. Undergr. Sp. 7, 246-252.
8
Itasca Consulting Group Inc., 2014, UDEC 6.0 User's Guide, Itasca Consulting Group Inc.
9
Itasca Consulting Group Inc., 2013, 3DEC 5.0 User's Guide, Itasca Consulting Group Inc.
10
Kwon, S. and K.B. Min, 2020, Fracture Transmissivity Evolution around the Geological Repository of Nuclear Waste Caused by Excavation Damage Zone, Thermoshearing and Glaciation. International Journal of Rock Mechanics and Mining Sciences (Submitted).
11
Lee, H.S., 2007, Analysis of Benchmark Test Model for Evaluation of Damage Characteristics of Rock Mass near Radioactive Waste Repository, Tunn. Undergr. Sp. 17(1), 32-42.
12
Lund, B., P. Schmidt and C. Hieronymus, 2009 Stress evolution and fault stability during the Weichselian glacial cycle. Waste Manag. SKB TR-09-15, Swedish Nuclear Fuel and Waste Management Co (SKB).
13
Meier, T. and T. Backers, 2020, DECOVALEX-2019 Task G Final Report, LBNL-2001266, Lawrence Berkeley National Laboratory (LBNL).
14
Min, K.B., J. Rutqvist, C.F. Tsang and L. Jing, 2004, Stress-dependent permeability of fractured rock masses: A numerical study, Int. J. Rock Mech. Min. Sci. 41(7), 1191-1210.
10.1016/j.ijrmms.2004.05.005
15
Min, K.B., J. Rutqvist, C.F. Tsang and L, Jing, 2005, Thermally induced mechanical and permeability changes around a nuclear waste repository - A far-field study based on equivalent properties determined by a discrete approach, Int. J. Rock Mech. Min. Sci. 42(5-6), 765-780.
10.1016/j.ijrmms.2005.03.014
16
Rutqvist, J., A. Bäckström, M. Chijimatsu, X.T. Feng, P.Z. Pan, J. Hudson, L. Jing, A. Kobayashi, T. Koyama, H.S. Lee, X.H. Huang, M. Rinne and B. Shen, 2009, A multiple-code simulation study of the long-term EDZ evolution of geological nuclear waste repositories, Environ. Geol. 57, 1313-1324.
10.1007/s00254-008-1536-1
17
Tsang, C.F., F. Bernier and C. Davies, 2005, Geohydromechanical processes in the Excavation Damaged Zone in crystalline rock, rock salt, and indurated and plastic clays - In the context of radioactive waste disposal, Int. J. Rock Mech. Min. Sci. 42(1), 109-125.
10.1016/j.ijrmms.2004.08.003
18
Tsang, C.F., O. Stephansson, L. Jing and F. Kautsky, 2009, DECOVALEX Project: from 1992 to 2007, Environ. Geol. 57, 1221-1237.
10.1007/s00254-008-1625-1
Information
  • Publisher :Korean Society for Rock Mechanics and Rock Engineering
  • Publisher(Ko) :한국암반공학회
  • Journal Title :Tunnel and Underground Space
  • Journal Title(Ko) :터널과 지하공간
  • Volume : 30
  • No :4
  • Pages :306-319
  • Received Date : 2020-07-31
  • Revised Date : 2020-08-24
  • Accepted Date : 2020-08-24
  • DOI :https://doi.org/10.7474/TUS.2020.30.4.306
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