The Grimsel test site—Part of the disposal project for radioactive waste in Switzerland

1986 ◽  
Vol 34 (1) ◽  
pp. 51-57
Author(s):  
Andreas L. Nold ◽  
Robert W. Lieb
Keyword(s):  
Radioactive Waste ◽  
Test Site ◽  
Grimsel Test Site

Potential coordinate mislocations in crosshole tomography: Results from the Grimsel test site, Switzerland

Geophysics ◽  
1997 ◽  
Vol 62 (6) ◽  
pp. 1696-1709 ◽  
Author(s):  
Hansruedi Maurer ◽  
Alan G. Green
Keyword(s):  
Radioactive Waste ◽  
Test Site ◽  
Swiss Alps ◽  
Low Velocity ◽  
Weak Anisotropy ◽  
Data Set ◽  
Tomographic Images ◽  
Wide Range ◽  
Grimsel Test Site ◽  
National Cooperative

Tomographic techniques based on borehole‐to‐borehole and tunnel‐to‐borehole traveltime data are now being employed in a wide range of studies associated with the exploration and exploitation of hydrocarbons and metallic minerals, the disposal of chemical and radioactive waste, diverse civil engineering projects, and archaeology. A fundamental assumption of currently employed tomographic inversion strategies is that the coordinates of the boreholes and tunnels containing the seismic sources and receivers are accurately known. By inverting both synthetic and observed traveltime data, we demonstrate that relatively minor coordinate errors (1–2%) in the deeper parts of long boreholes (>100 m) may produce artifacts in the tomographic images that are comparable in extent and amplitude to true velocity anomalies. To address this problem, we introduce the coupled inverse method, commonly used in earthquake studies, as a means to determine simultaneously borehole coordinate adjustments and an estimate of the tomographic image. This method has been applied to traveltime data generated and collected along a tunnel and in three boreholes within a granitic body situated in the central Swiss Alps (Grimsel test site operated by NAGRA, the Swiss National Cooperative for the Disposal of Radioactive Waste). Coupled inversions of two independent subsets of traveltime data that involve a common central borehole, together with a coupled inversion of the entire data set, yield consistent coordinate adjustments for all boreholes and tomographic images that are compatible with the known geology and a sonic log from the central borehole. Further tests with synthetic data demonstrate that certain types of weak anisotropy could influence the coupled inversions. Regardless of whether minor coordinate mislocations or weak anisotropy is the dominant effect at the Grimsel test site, distinct low‐velocity zones appear to delineate fractures zones that are conduits for groundwater flow.

Grimsel Test Site - The Next Decades

2002 ◽  
Vol 757 ◽  
Author(s):  
Stratis Vomvoris ◽  
Wolfgang Kickmaier ◽  
Ian G. McKinley
Keyword(s):  
Radioactive Waste ◽  
Waste Management ◽  
Time Scales ◽  
Test Site ◽  
Radioactive Waste Management ◽  
Grimsel Test Site

ABSTRACTThe Grimsel Test Site, which has been in operation since 1984, is known in the radioactive waste management community for the scope and quality of the experiments and projects performed over the last two decades. This paper will overview Nagra's commitments and the current plans for future activities in association with Grimsel, which are being developed considering time scales of the order of a decade or more.

Modeling of an in-situ diffusion experiment in granite at the Grimsel Test Site

2014 ◽  
Vol 1665 ◽  
pp. 85-91 ◽  
Author(s):  
Josep M. Soler ◽  
Jiri Landa ◽  
Vaclava Havlova ◽  
Yukio Tachi ◽  
Takanori Ebina ◽  
...  
Keyword(s):  
Effective Diffusion ◽  
Test Site ◽  
Diffusion Experiment ◽  
Bulk Rock ◽  
Disturbed Zone ◽  
Mean Grain Size ◽  
Grimsel Test Site ◽  
In Situ Diffusion

ABSTRACTMatrix diffusion is a key process for radionuclide retention in crystalline rocks. Within the LTD project (Long-Term Diffusion), an in-situ diffusion experiment in unaltered non-fractured granite was performed at the Grimsel Test Site (www.grimsel.com, Switzerland). The tracers included 3H as HTO, 22Na+, 134Cs+ and 131I- with stable I- as carrier.The dataset (except for 131I- because of complete decay) was analyzed with different diffusion-sorption models by different teams (NAGRA / IDAEA-CSIC, UJV-Rez, JAEA, Univ. Poitiers) using different codes, with the goal of obtaining effective diffusion coefficients (De) and porosity (ϕ) or rock capacity (α) values. A Borehole Disturbed Zone (BDZ), which was observed in the rock profile data for 22Na+ and 134Cs+, had to be taken into account to fit the experimental observations. The extension of the BDZ (1-2 mm) was about the same magnitude as the mean grain size of the quartz and feldspar grains.De and α values for the different tracers in the BDZ are larger than the respective values in the bulk rock. Capacity factors in the bulk rock are largest for Cs+ (strong sorption) and smallest for 3H (no sorption). However, 3H seems to display large α values in the BDZ. This phenomenon will be investigated in more detail in a second test starting in 2013.

Studies on radionuclide transport behaviour–The next generation of in-situ experiments at the Grimsel Test Site

2009 ◽  
Vol 1193 ◽  
Author(s):  
Andrew James Martin ◽  
Ingo Blechschmidt
Keyword(s):  
Shear Zone ◽  
Diffusion Processes ◽  
Test Site ◽  
Core Material ◽  
Laboratory Studies ◽  
Grimsel Test Site ◽  
And Migration ◽  
Colloid Formation

AbstractTwo recent ongoing major projects at the Grimsel Test Site (GTS) (www.grimsel.com) that were initiated to simulate the long-term behaviour of radionuclides in the repository near-field and the surrounding host rock are presented: the Colloid Formation and Migration (CFM) project, which focuses on colloid generation and migration from a bentonite source doped with radionuclides and the Long-Term Diffusion (LTD) project, which aims at in-situ verification and understanding of the processes that control the long-term diffusion of repository-relevant radionuclides. So far, the CFM project has principally involved: development and implementation of a state-of-the-art sealing concept to control hydraulic gradients in a shear zone to imitate repository-relevant conditions; extensive laboratory studies to examine bentonite erosion and colloid formation in a shear zone; and, development of models to estimate colloid formation and migration. The next stage will be to assess the behavior of bentonite colloids generated from a radionuclide spiked bentonite source-term emplaced into the controlled flow field of the shear zone. This will be coupled with further extensive laboratory studies in order to refine and evaluate the colloid models currently used in performance assessments. The LTD project consists of: a monopole diffusion experiment where weakly sorbing and non-sorbing radionuclides (3H, 22Na, 131I, 134Cs) have been circulating and diffusing into undisturbed rock matrix since June 2007; experiments to characterise pore space geometry, including determination of in-situ porosity with 14C doped MMA resin for comparison with laboratory derived data; a study of natural tracers to elucidate evidence of long-term diffusion processes; and, an investigation of the in-situ matrix diffusion paths in core material from earlier GTS experiments. Future experiments will focus on diffusion processes starting from a water-conducting feature under realistic boundary conditions.

Numerical Modeling of the Gas Migration Test at the Grimsel Test Site (Switzerland)

2008 ◽  
Vol 164 (2) ◽  
pp. 155-168 ◽  
Author(s):  
Rainer Senger ◽  
Bill Lanyon ◽  
Paul Marschall ◽  
Stratis Vomvoris ◽  
Ai Fujiwara
Keyword(s):  
Numerical Modeling ◽  
Test Site ◽  
Gas Migration ◽  
Migration Test ◽  
Grimsel Test Site

Recurrent fault activity in the Grimsel Test Site (GTS, Switzerland): revealed by Rb-Sr, K-Ar and tritium isotope techniques

1992 ◽  
Vol 149 (2) ◽  
pp. 293-301 ◽  
Author(s):  
M. KRALIK ◽  
N. CLAUER ◽  
R. HOLNSTEINER ◽  
H. HUEMER ◽  
F. KAPPEL
Keyword(s):  
Test Site ◽  
Fault Activity ◽  
Isotope Techniques ◽  
Grimsel Test Site

scholarly journals The seismo-hydro-mechanical behaviour during deep geothermal reservoir stimulations: open questions tackled in a decameter-scale in-situ stimulation experiment

2017 ◽  
Author(s):  
Florian Amann ◽  
Valentin Gischig ◽  
Keith Evans ◽  
Joseph Doetsch ◽  
Reza Jalali ◽  
...  
Keyword(s):  
Rock Mass ◽  
Geothermal Energy ◽  
Numerical Models ◽  
Test Site ◽  
Crystalline Rock ◽  
Coupled Processes ◽  
Small Scale ◽  
Intermediate Scale ◽  
Grimsel Test Site

Abstract. In this contribution we present a review of scientific research results that address seismo-hydro-mechanical coupled processes relevant for the development of a sustainable heat exchanger in low permeability crystalline rock and introduce the design of the In-situ Stimulation and Circulation (ISC) experiment at the Grimsel Test Site dedicated to study such processes under controlled conditions. The review shows that research on reservoir stimulation for deep geothermal energy exploitation has been largely based on laboratory observations, large-scale projects and numerical models. Observations of full-scale reservoir stimulations have yielded important results. However, the limited access to the reservoir and limitations in the control on the experimental conditions during deep reservoir stimulations is insufficient to resolve the details of the hydro-mechanical processes that would enhance process understanding in a way that aids future stimulation design. Small scale laboratory experiments provide a fundamental insights into various processes relevant for enhanced geothermal energy, but suffer from 1) difficulties and uncertainties in upscaling the results to the field-scale and 2) relatively homogeneous material and stress conditions that lead to an over-simplistic fracture flow and/or hydraulic fracture propagation behaviour that is not representative for a heterogeneous reservoir. Thus, there is a need for intermediate-scale hydraulic stimulation experiments with high experimental control that bridge the various scales, and for which access to the target rock mass with a comprehensive monitoring system is possible. Only few intermediate-scale hydro-shearing and hydro-fracturing experiments have recently been performed in a densely instrumented rock mass. No such measurements have been performed on faults in crystalline basement rocks. The In-situ Stimulation and Circulation (ISC) experiment currently performed in a naturally fractured and faulted crystalline rock mass at the Grimsel Test Site (Switzerland) is designed to address open research questions, which could not be investigated in the required detail so far. Two hydraulic injection phases were executed to enhance the permeability of the rock mass: a hydro-shearing phase and then a hydraulic fracturing phase. During the injection phases the rock mass deformation across fractures and within intact rock, the pore pressure distribution and propagation and the micro-seismic response were monitored at a high spatial and temporal resolution.

Results of the colloid and radionuclide retention experiment (CRR) at the Grimsel Test Site (GTS), Switzerland – impact of reaction kinetics and speciation on radionuclide migration

2004 ◽  
Vol 92 (9-11) ◽  
Author(s):  
Horst Geckeis ◽  
Thorsten Schäfer ◽  
W. Hauser ◽  
Thomas Rabung ◽  
T. Missana ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Test Site ◽  
Radionuclide Migration ◽  
Migration Behaviour ◽  
Grimsel Test Site

SummaryThe influence of smectite colloids on the migration behaviour of U(VI), Th(IV), Pu(IV), Am(III), Np(V), Sr(II) and Cs(I) is investigated within the Colloid and Radionuclide Retardation experiment (CRR). Two

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