Diffusion in the Matrix of Granitic Rock Field Test in the Stripa Mine

1987 ◽  
Vol 112 ◽  
Author(s):  
Lars Birgersson ◽  
Ivars Neretnieks
Keyword(s):  
Granitic Rock ◽  
Nuclear Waste Repository ◽  
Filling Material ◽  
Rock Matrix ◽  
In Situ Experiment ◽  
Undisturbed Rock ◽  
Disturbed Zone ◽  
The Matrix ◽  
Stress Environment

AbstractThree similar migration experiments in the matrix of granitic rock are presented. The experiments have been carried out in “undisturbed” rock, that is rock under its natural stress environment. Since the experiments were performed at the 360 m level (in the Stripa Mine), the rock was subjected to nearly the same conditions as the rock surrounding a nuclear waste repository as proposed in the Swedish concept (SKB).A mixture of three non-sorbing (conservative) tracers, Uranine, Cr-EDTA and I−, were injected into the granitic rock matrix for time periods of months up to years. The subsequent overcorings of the injection holes showed that the tracers had in some cases migrated at least ≈ 400 mm (measuring limit) into the rock matrix for the experiment with the longest injection time. It could also be seen that there were large differences in migration distance into the rock matrix for samples taken fairly close to each other. One example where the tracers have diffused through fissure coating (filling) material located in “undisturbed” rock is also presented.The results from all three experiments show that all three tracers have migrated through the disturbed zone close to the injection hole, through the fissure coating material and a distance into the “undisturbed” rock matrix.These results therefore indicate that dissolved compounds may migrate into the rock matrix. This migration into the rock matrix will increase the area available for sorption of radionuclides significantly and may therefore increase the migration times for radionuclides by order(s) of magnitude.Diffusivities and hydraulic conductivities obtained in this in-situ experiment compare well with those obtained in laboratory experiments.

Diffusion in the Matrix of Granitic Rock Field Test in the Stripa Mine Part 2.

1983 ◽  
Vol 26 ◽  
Author(s):  
Lars Birgersson ◽  
Ivars Neretnieks
Keyword(s):  
Laboratory Experiments ◽  
Granitic Rock ◽  
Nuclear Waste Repository ◽  
Rock Matrix ◽  
Injection Hole ◽  
Undisturbed Rock ◽  
Natural Stress ◽  
The Matrix ◽  
Migration Experiment ◽  
Stress Environment

ABSTRACTA migration experiment in the rock matrix is presented. The experiment has been carried out in “undisturbed” rock, that is in rock under its natural stress environment. Since the experiment was performed at the 360 m-level (in the Stripa mine), the rock was subject to nearly the same conditions as the rock surrounding a nuclear waste repository as proposed in the Swedish concept (KBS).The results show that all three tracers (Cr-EDTA, Uranine and 1-) have passed the zone disturbed by the presence of the injection hole and migrated some distance into “undisturbed” rock.These results indicate the existence of a connected micro fissure system in undisturbed rock, in which tracers (and therefore radionuclides) can migrate. Diffusivities obtained in this experiment are comparable to those obtained in laboratory experiments.

Migration in a Single Fracture in Granitic Rock

1983 ◽  
Vol 26 ◽  
Author(s):  
Harald Abelin ◽  
Jard Gidlund ◽  
Luis Moreno ◽  
Ivars Neretnieks
Keyword(s):  
Experimental Design ◽  
Field Data ◽  
Granitic Rock ◽  
Breakthrough Curves ◽  
Short Description ◽  
Hydrodynamic Dispersion ◽  
Single Fracture ◽  
Rock Matrix ◽  
In Situ Experiment

ABSTRACTAn in situ experiment to study migration in a single fracture in granitic rock has been performed. Both sorbing and nonsorbing tracers have been used. Results from a tracer run with a nonsorbing tracer (Uranine) are presented. The breakthrough curves have been explored with a model which takes into account hydrodynamic dispersion as well as diffusion into the rock matrix. Diffusivities and porosities of the rock matrix measured in the laboratory are used to interpret the field data. A short description of the experimental design is given. This investigation is a part of the STRIPA PROJECT phase I.

Diffusion in the Matrix of Granitic Rock. Field Test in the Stripa Mine

1981 ◽  
Vol 11 ◽  
Author(s):  
Lars Birgersson ◽  
Ivars Neretnieks
Keyword(s):  
Field Test ◽  
Granitic Rock ◽  
Pore System ◽  
Undisturbed Rock ◽  
The Matrix ◽  
Migration Experiment

A migration experiment with the objective to investigate the existence of a connected pore system in undisturbed rock has been performed in the Stripa mine at the 360 m-level.

Determination of the Porosity, Permeability and Diffusivity of Rock in the Excavation-Disturbed Zone Around Full-Scale Deposition Holes Using the He-Gas Method

1999 ◽  
Vol 556 ◽  
Author(s):  
J. Autio ◽  
J. Timonen ◽  
T. Aaltonen ◽  
M. Laajalahti ◽  
K. Kuoppamäki ◽  
...  
Keyword(s):  
Nuclear Waste ◽  
Granitic Rock ◽  
Nuclear Waste Repository ◽  
Direction Parallel ◽  
Disturbed Zone ◽  
Excavation Disturbed Zone ◽  
Waste Repository ◽  
Effective Diffusivities ◽  
Scale Deposition

AbstractIn a nuclear waste repository, rock in the excavation-disturbed zone adjacent to the walls of deposition holes for waste canisters is a potential pathway for the transport of corrosive agents and radionuclides. Three experimental holes the size of deposition holes in a KBS-3 type repository (depth 7.5 m and diameter 1.5 m) were bored in hard granitic rock in the Research Tunnel at Olkiluoto and the porosities, effective diffusivities and permeabilities of rock in the excavation-disturbed zone were determined in a direction parallel to the disturbed surface using He-gas methods. Permeability and diffusivity in a direction parallel to the rock schistosity was found to be clearly larger than in a direction perpendicular to it.

Channeling and its Potential Consequences for Radionuclides Transport

1987 ◽  
Vol 112 ◽  
Author(s):  
Luis Moreno ◽  
Ivars Neretnieks
Keyword(s):  
Water Flow ◽  
Granitic Rock ◽  
Flow Distribution ◽  
Crystalline Rock ◽  
Fractured Media ◽  
Radionuclide Transport ◽  
Rock Matrix ◽  
Sorption Coefficient ◽  
The Matrix ◽  
Large Flow

SummaryRadionuclide transport through fractured media is usually calculated assuming that water flows in most of the fractures. Several observations in the field and the laboratory show that flow is very unevenly distributed in fractured crystalline rock. These observations indicate that most of the water flow takes place in a limited number of channels. The channels are seldom wider than a few meters and are often much narrower. This means that the surface of the fracture in contact with the flowing water (wetted surface) is less than one might expect.This low value of the wet surface of the fracture may considerably influence the transport of radionuclides through fractured media. If the channels do not intersect over a certain distance, then the channels may be modelled as a bundle of independent channels. Channels with a large flow and small sorption surface will carry the tracer rapidly and in large amounts.Calculations are performed for cases where channeling is assumed to take place. The most important entities to assess are the water flow distribution in the different channels, the wetted surface of the channels, the diffusivity into the rock matrix, and the sorption coefficient in the matrix. Experimental data for the water flow distribution are used and the transport of nuclides is calculated for the different channels. From these values the concentration of the effluent is determined. The results show that the retardation for the nonsorbing nuclides is negligible. Retardation is only important for the nuclides which are strongly sorbed on the granitic rock. Calculations are also done assuming other channel frequencies and other overall water flowrates.

scholarly journals Characterization of Granitic Rock by means of the Borehore Radar. On the Result of the Measurements at the Kamaishi Mine in-situ Experiment Site.

1992 ◽  
Vol 32 (6) ◽  
pp. 304-312
Author(s):  
Takeshi SEMBA ◽  
Nobuhisa OGATA ◽  
Ken HASEGAWA ◽  
Hiroshi IWASAKI ◽  
Kunio WATANABE
Keyword(s):  
Granitic Rock ◽  
In Situ Experiment

Determination of the Structure and Porosity of Rock in the Disturbed Zone Around Experimental Full-Scale Deposition Holes Using the 14C-PMMA Method

1997 ◽  
Vol 506 ◽  
Author(s):  
J. Autio ◽  
M. Slltari-Kauppi
Keyword(s):  
Granitic Rock ◽  
Gradual Transition ◽  
Nuclear Waste Repository ◽  
Gas Release ◽  
The Novel ◽  
Transport Pathway ◽  
Bentonite Buffer ◽  
Disturbed Zone ◽  
Scale Deposition

ABSTRACTIn a nuclear waste repository the disturbed rock zone adjacent to the deposition holes of waste canisters is a potential transport pathway of radionuclides. The properties of the disturbed zone may also play an important role in the saturation of the bentonite buffer and in gas release.Three experimental holes of the size of deposition holes (depth 7.5 m and diameter 1.5 m) in a KBS-3 type repository were bored in hard granitic rock in the Research Tunnel at Olkiluoto. The disturbed rock zone caused by the boring was analyzed including determination of the porosity and structure of the disturbed and intact rock. These were studied in the laboratory using core samples by using the novel 14C-polymethylmethacrylate (14C-PMMA) method. In addition the structure of the disturbed zone was also examined using scanning electron and optical microscopy. A distinct zone of disturbance adjacent to the surface of the deposition holes was found. This disturbed zone was further divided into three separate sub-zones with gradual transition between the zones. It was also observed that the machine and tool factors have effect on the properties of the disturbed zone.

scholarly journals Supramolecular ionic polymer/carbon nanotube composite hydrogels with enhanced electromechanical performance

2020 ◽  
Vol 9 (1) ◽  
pp. 478-488 ◽  
Author(s):  
Yun-Fei Zhang ◽  
Fei-Peng Du ◽  
Ling Chen ◽  
Ka-Wai Yeung ◽  
Yuqing Dong ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Ion Mobility ◽  
Artificial Muscles ◽  
Ionic Polymer ◽  
Composite Hydrogels ◽  
The Matrix ◽  
Electromechanical Performance ◽  
Carbon Nanotube Composite ◽  
Robotic Devices

AbstractElectroactive hydrogels have received increasing attention due to the possibility of being used in biomimetics, such as for soft robotics and artificial muscles. However, the applications are hindered by the poor mechanical properties and slow response time. To address these issues, in this study, supramolecular ionic polymer–carbon nanotube (SIPC) composite hydrogels were fabricated via in situ free radical polymerization. The polymer matrix consisted of carbon nanotubes (CNTs), styrene sulfonic sodium (SSNa), β-cyclodextrin (β-CD)-grafted acrylamide, and ferrocene (Fc)-grafted acrylamide, with the incorporation of SSNa serving as the ionic source. On applying an external voltage, the ions accumulate on one side of the matrix, leading to localized swelling and bending of the structure. Therefore, a controllable and reversible actuation can be achieved by changing the applied voltage. The tensile strength of the SIPC was improved by over 300%, from 12 to 49 kPa, due to the reinforcement effect of the CNTs and the supramolecular host–guest interactions between the β-CD and Fc moieties. The inclusion of CNTs not only improved the tensile properties but also enhanced the ion mobility, which lead to a faster electromechanical response. The presented electro-responsive composite hydrogel shows a high potential for the development of robotic devices and soft smart components for sensing and actuating applications.

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