Assessing in situ Radionuclide Migration from Natural Analog Studies: Response to McKinley and Alexander (1996)

1998 ◽  
Vol 80 (4) ◽  
Author(s):  
Teh-Lung Ku ◽  
Shangde Luo ◽  
Bret W. Leslie ◽  
Douglas E. Hammond
Keyword(s):  
Radionuclide Migration ◽  
Natural Analog

Leaching and migration of Np, Pu, and Am from α-doped SON68 HLW glass in contact with dense clay

2006 ◽  
Vol 932 ◽  
Author(s):  
Elie Valcke ◽  
Mireille Gysemans ◽  
Hugo Moors ◽  
Pierre Van Iseghem ◽  
Nicole Godon ◽  
...  
Keyword(s):  
Glass Frit ◽  
High Density ◽  
Radionuclide Migration ◽  
Colloidal Transport ◽  
Boom Clay ◽  
Backfill Materials ◽  
Powdered Glass ◽  
And Migration ◽  
Radionuclide Leaching

ABSTRACTIn the frame of an integrated in situ test on the alteration of the SON68 reference glass in realistic disposal conditions, the leaching of Np, Pu, and Am from α-doped SON68 glass samples and their migration in three clay-based backfill materials at high density was measured. The addition of powdered glass frit to a Ca-bentonite decreased the glass alteration by two orders of magnitude, and resulted in a concomitant decrease of the radionuclide leaching in comparison with dried Boom Clay, which is the more agressive backfill. All actinides were selectively retained in the alteration layer, but the retention degree was lower for Np than for Pu and Am. All backfill materials proved to be efficient barriers against radionuclide migration. For nearly all radionuclides and backfill materials, the migration profile showed a contribution of colloidal transport.

Site Characterization for Field Radionuclide Migration Studies in Climax Granite

1981 ◽  
Vol 6 ◽  
Author(s):  
Dana Isherwood ◽  
Ellen Raber ◽  
Randolph Stone
Keyword(s):  
Flow Model ◽  
Test Site ◽  
Hydraulic Testing ◽  
Nevada Test Site ◽  
Radionuclide Migration ◽  
Critical Question ◽  
Initial Field ◽  
In Situ Conditions ◽  
Fracture Apertures

ABSTRACTRadionuclide migration experiments in fractured granite at the Climax Stock, Nevada Test Site, are needed to compare field and laboratory measured retardation factors to determine whether laboratory studies accurately reflect in situ conditions. Initial field activities have concentrated on hydrological investigations to determine whether the fractures in Climax granite are suitable for migration experiments. A critical question was whether we could isolate a single vertical fracture between two boreholes and establish flow along that fracture from an upper to a lower borehole. Of the ten fractures tested, one fracture would not take water at pressures up to 200 psig for 24 hours. Several fractures were so permeable they accepted water at a rate which exceeded the pumping capacity of the equipment. Other fractures failed to show a connection between the two boreholes. In two fractures, we were able to establish a circulating system with up to 95 percent of the injected water being recovered. Constant pressure injection tests were conducted. Intrinsic permeabilities of 33 and 75 (μm)2 were estimated using a radial nonsteady flow model. These values correspond to effective fracture apertures of 20 and 30 μm respectively. Concurrent with the hydraulic testing activities is a study of the Climax ground-water chemistry. Our analyses show the natural water to be very different in composition from the granite equilibrated water used in laboratory sorption studies. This paper includes the results of the hydrogeological and geochemical investigations, and describes the overall experimental design plans for the radionuclide migration experiments.

Kaolinite as an in situ dosimeter for past radionuclide migration at the Earth's surface

1998 ◽  
Vol 13 (6) ◽  
pp. 751-765 ◽  
Author(s):  
Thierry Allard ◽  
Jean-Pierre Muller
Keyword(s):  
Radionuclide Migration

Transport of 14C and Uranium in the Carrizo Aquifer of South Texas, a Natural Analog of Radionuclide Migration

1983 ◽  
Vol 26 ◽  
Author(s):  
Robert W. Andrews ◽  
F. J. Pearson
Keyword(s):  
Ground Water ◽  
Water Flow ◽  
South Texas ◽  
Performance Assessments ◽  
Ground Water Flow ◽  
Radionuclide Migration ◽  
Natural Analog ◽  
Fraction Distribution ◽  
Nuclide Transport ◽  
Best Fit

ABSTRACTGround-water flow and transport were modeled along a one-dimensional, vertical cross-section of the Carrizo aquifer from its outcrop down gradient for 100 km. Using a constant flux of 14C at the recharge boundary, the 14C mass fraction distribution downgradient was simulated until steady-state was attained. The match between the observed data and simulated results is excellent for a porosity of 35% and a KD of zero. The transport of both 234U and 238U was simulated with varying retardation coefficients. The best fit occurred with a RD of about 30, which corresponds to a KD of 6. The results indicate that modeling may be reliably conducted over time periods and distances of interest in radionuclide transport performance assessments and that regionally averaged hydrologic properties can provide appropriate values for predicting ground-water flow and nuclide transport.

scholarly journals Mathematical Modelling of Fault Reactivation Induced by Water Injection

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 282 ◽  
Author(s):  
Thanh Son Nguyen ◽  
Yves Guglielmi ◽  
Bastian Graupner ◽  
Jonny Rutqvist
Keyword(s):  
Induced Seismicity ◽  
Water Injection ◽  
In Situ Stress ◽  
Fault Reactivation ◽  
Shear Strength Parameters ◽  
Radionuclide Migration ◽  
Strength Parameters ◽  
Mont Terri ◽  
Underground Research Laboratory

Faults in the host rock that might exist in the vicinity of deep geological repositories for radioactive waste, constitute potential enhanced pathways for radionuclide migration. Several processes might trigger pore pressure increases in the faults leading to fault failure and induced seismicity, and increase the faults’ permeability. In this research, we developed a mathematical model to simulate fault activation during an experiment of controlled water injection in a fault at the Mont-Terri Underground Research Laboratory in Switzerland. The effects of in-situ stress, fault shear strength parameters and heterogeneity are assessed. It was shown that the above factors are critical and need to be adequately characterized in order to predict the faults’ hydro-mechanical behaviour.

The Assessment of Radionuclide Retardation in Fractured Crystalline Rocks

1997 ◽  
Vol 506 ◽  
Author(s):  
W. Russell Alexander ◽  
Kunio Ota ◽  
Bernhard Frieg ◽  
Ian G. Mckinley
Keyword(s):  
Test Site ◽  
Breakthrough Curves ◽  
Swiss Alps ◽  
Radionuclide Migration ◽  
Sorption Data ◽  
Kd Values ◽  
Long Term Experiment ◽  
Fractured Crystalline Rocks ◽  
Tracer Migration

ABSTRACTThe joint Nagra/PNC Radionuclide Migration Programme has been running for over ten years in Nagra‘s Grimsel Test Site in the central Swiss Alps. The programme is specifically aimed at the further development of conceptual models of radionuclide transport in the geosphere, rigorously testing the applicability of current transport codes to quantify radionuclide migration in situ and assessing how successfully laboratory sorption data (specifically, Kd values) may be extrapolated to in situ conditions to predict radionuclide retardation in the geosphere [1]. A large series of field tracer migration experiments was carried out in a hydrologically well characterised water-bearing, complex fracture (or shear zone), increasing in complexity from simple, nonsorbing fluoresceine (a fluorescent dye), 3H, 3,4He, 82Br and 123I through weakly sorbing 22.24Na,85Sr and 86Rb to a final, long-term experiment with moderately sorbing 134,137Cs. The radionuclides were injected into a dipole flow field where the flowpath length, dipole width or shape and groundwater flow velocity were all varied. After a considerable learning period, generally good fits could be obtained between transport code predictions and subsequent field tracer breakthrough curves, suggesting that the transport codes tested were a reasonable representation of in situ conditions.

The Radlonuclide Migration Experiment at the Grimsel Rock Laboratory, Switzerland

1987 ◽  
Vol 112 ◽  
Author(s):  
Ian G. McKinley ◽  
W. Russell Alexander ◽  
Claudine Bajo ◽  
Urs Frick ◽  
Jörg Hadermann ◽  
...  
Keyword(s):  
Safety Assessment ◽  
Crystalline Rock ◽  
Radionuclide Migration ◽  
Support Programme ◽  
Rock Laboratory ◽  
First Results ◽  
Migration Experiment ◽  
Site Characterisation

AbstractThis paper describes the programme for an in-situ radionuclide migration experiment in fractured crystalline rock and presents the first results of site characterisation work. This study is particularly notable for its extensive hydrologic/geochemical support programme and the use of radiotracers identified as important in safety assessment studies.

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