scholarly journals Modeling coupled thermal–hydrological–chemical processes in the unsaturated fractured rock of Yucca Mountain, Nevada: Heterogeneity and seepage

2006 ◽  
Vol 31 (10-14) ◽  
pp. 626-633 ◽  
Author(s):  
S. Mukhopadhyay ◽  
E.L. Sonnenthal ◽  
N. Spycher
Keyword(s):  
Fractured Rock ◽  
Yucca Mountain ◽  
Chemical Processes

Migration of Solutes in Unsaturated, Fractured Rock at Yucca Mountain: Measurements, Mechanisms, and Models

1995 ◽  
Vol 412 ◽  
Author(s):  
A. V. Wolfsberg ◽  
B. A. Robinson ◽  
J. T. Fabryka-Martin
Keyword(s):  
Solute Transport ◽  
Transport Model ◽  
Alternative Hypothesis ◽  
Fractured Rock ◽  
Yucca Mountain ◽  
Nuclear Waste Repository ◽  
Transport Studies ◽  
And Performance ◽  
High Level ◽  
A Site

AbstractCharacterization and performance assessment (PA) studies for the potential high-level nuclear waste repository at Yucca Mountain require an understanding of migration mechanisms and pathways of radioactive solutes. Measurements of 36C1 in samples extracted from boreholes at the site are being used in conjunction with recent infiltration estimates to calibrate a site-scale flow and solute transport model. This exercise using the flow and solute transport model, FEHM, involves testing different model formulations and two different hypotheses to explain the occurrence of elevated 36Cl in the Calico Hills unit (CHn) which indicates younger water than in the overlying Topopah Spring unit (TSw). One hypothesis suggests fast vertical transport from the surface via fractures in the TSw to the CHn. An alternative hypothesis is that the elevated 36C1 concentrations reflect rapid horizontal flow in the CHn or at the interface between the CHn and the TSw with the source being vertical percolation under spatially isolated regions of high infiltration or at outcrops of those units. Arguments in favor of and against the hypotheses are described in conjunction with the site-scale transport studies.

Simulation of Radionuclide Transport through Unsaturated, Fractured Rock: Application to Yucca Mountain, Nevada

2012 ◽  
Vol 11 (4) ◽  
pp. vzj2011.0142 ◽  
Author(s):  
Bruce A. Robinson ◽  
Shaoping Chu ◽  
Zhiming Lu
Keyword(s):  
Fractured Rock ◽  
Yucca Mountain ◽  
Radionuclide Transport

scholarly journals Evaluating the Moisture Conditions in the Fractured Rock at Yucca Mountain: The Impact of Natural Convection Processes in Heated Emplacement Drifts

2006 ◽  
Vol 5 (4) ◽  
pp. 1172-1193 ◽  
Author(s):  
J. T. Birkholzer ◽  
S. W. Webb ◽  
N. Halecky ◽  
P. F. Peterson ◽  
G. S. Bodvarsson
Keyword(s):  
Natural Convection ◽  
Fractured Rock ◽  
Yucca Mountain ◽  
Moisture Conditions ◽  
The Impact

The Modification and Application of the Geochemical Modelling Code CHEQMATE to Simulate Transport and Chemical Processes within Fractured Media

1993 ◽  
Vol 333 ◽  
Author(s):  
A. V. Chambers ◽  
A.C. Smith
Keyword(s):  
Fractured Rock ◽  
Chemical Processes ◽  
Fractured Media ◽  
Single Fracture ◽  
Radionuclide Transport ◽  
Continuum Approach ◽  
Multiple Fractures ◽  
Intermediate Level Radioactive Waste ◽  
The Uk ◽  
Fracture Distribution

ABSTRACTThe UK current plans for a repository for the disposal of intermediate-level radioactive waste involve the use of a cementitious backfill within the repository vaults. Radionuclide transport could be concentrated within cracks that may form in the cement, or in fractures within the rock surrounding the repository. A version of CHEQMATE (CHemical EQuilibrium with Migration And Transport Equations) that includes a representation of transport through fractured media has been developed. This paper describes modifications of the code, to allow simulation of transport through either a single fracture, or, by adopting a continuum approach to represent fracture distribution, through multiple fractures. Successful verification of the modified program against analytical solutions for transport through fractured rock and cracked cementitious media is presented. An application of the modified program to study the evolution of the aqueous chemistry within a repository vault containing a single fracture through the cementitious backfill is also discussed.

scholarly journals Well-Doublets: A First-Order Assessment of Geothermal SedHeat Systems

2021 ◽  
Vol 11 (2) ◽  
pp. 697
Author(s):  
Seyed Bijan Mahbaz ◽  
Ali Yaghoubi ◽  
Alireza Dehghani-Sanij ◽  
Erfan Sarvaramini ◽  
Yuri Leonenko ◽  
...  
Keyword(s):  
Fractured Rock ◽  
Pressure Change ◽  
Chemical Processes ◽  
Hot Water ◽  
First Order ◽  
Geothermal Well ◽  
Transfer Processes ◽  
Energy Needs ◽  
Temperature And Pressure ◽  
Fractured Rock Masses

Renewable and sustainable energy sources can play an important role in meeting the world’s energy needs and also in addressing environmental challenges such as global warming and climate change. Geothermal well-doublet systems can produce both electrical and thermal energy through extracting heat from hot-water aquifers. In this paper, we examine some potential challenges associated with the operation of well-doublet systems, including heat conductivity, chemical, and mechanical issues. In these systems, geomechanics issues such as thermal short-circuiting and induced seismicity arise from temperature and pressure change impacts on the stress state in stiff rocks and fluid flow in fractured rock masses. Coupled chemical processes also can cause fluid channeling or formation and tubular goods plugging (scaling) with precipitates. Mechanical and chemical disequilibrium conditions lead to increased production uncertainties; hence risk, and therefore coupled geo-risk assessments and optimization analyses are needed for comparative commercialization evaluations among different sites. The challenges related to heat transfer processes are also examined. These studies can help better understand the issues that may arise during the operation of geothermal well-doublet systems and improve their effectiveness, subsequently reducing associated costs and risks.

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