scholarly journals The Hydrothermal Stability of Cement Sealing Materials in the Potential Yucca Mountain High Level Nuclear Waste Repository

1991 ◽  
Vol 245 ◽  
Author(s):  
J. L. Krumhansl ◽  
T. E. Hinkebein ◽  
J. Myers
Keyword(s):  
Geochemical Modeling ◽  
Test Site ◽  
Cementitious Materials ◽  
Yucca Mountain ◽  
Nuclear Waste Repository ◽  
X Ray Diffraction ◽  
Nevada Test Site ◽  
Post Test ◽  
High Level ◽  
Modeling Code

ABSTRACTCementitious materials, together with other materials, are being considered to seal a potential repository at Yucca Mountain. A concern with cementitious materials is the chemical and mineralogic changes that may occur as these materials age while in contact with local ground waters. A combined theoretical and experimental approach was taken to determine the ability to theoretically predict mineralogic changes. The cementitious material selected for study has a relatively low Ca:Si ratio approaching that of the mineral tobermorite. Samples were treated hydrothermally at 200°C with water similar to that obtained from the J-13 well on the Nevada Test Site. Post-test solutions were analyzed for pH as well as dissolved K, Na, Ca, Al, and Si. Solid phases formed during these experiments were characterized by scanning electron microscopy and X-ray diffraction. These findings were compared with predictions made by the geochemical modeling code EQ3NR/EQ6. It was generally found that there was good agreement between predicted and experimental results.

Evaporative Evolution of Brines from Synthetic Topopah Spring Tuff Pore Water, Yucca Mountain, NV

2002 ◽  
Vol 757 ◽  
Author(s):  
Maureen Alai ◽  
Susan Carroll
Keyword(s):  
Pore Water ◽  
Yucca Mountain ◽  
Nuclear Waste Repository ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Level Nuclear Waste ◽  
Series Of Experiments ◽  
High Level ◽  
Topopah Spring Tuff

ABSTRACTWe are investigating the evaporation of pore water representative of the designated high-level-nuclear-waste repository at Yucca Mountain, NV to predict the range of brine compositions that may contact waste containers. These brines could form potentially corrosive thin films on the containers and impact their long-term integrity. Here we report the geochemistry of a relatively complex synthetic Topopah Spring Tuff pore water that was progressively evaporated in a series of experiments. The experiments were conducted in a vented vessel in which HEPA filtered air flowed over the 95°C solution. Samples of the evaporating solution and the condensed vapor were taken and analyzed to determine the evolving water chemistry and gas volatility. The final solid was analyzed by X-ray diffraction.The synthetic Topopah Spring Tuff water evolved towards a complex brine that contained about 45 mol % Cl, 7 mol% NO3, 43 mol% Na, 4 mol % K, and less than 1 mol % each of SO4, Ca, Mg, HCO3 and Si. Trends in the solution data and identification of CaSO4 solids suggest that fluorite, carbonate, sulfate, and Mg-silicate precipitation minimize the corrosion potential of “sulfate type pore water” by removing F, Ca, and Mg during the early stages of evaporation.

Numerical Simulation of Flow and Transport in Fractured Tuff

1983 ◽  
Vol 26 ◽  
Author(s):  
B. J. Travis ◽  
S. W. Hodson ◽  
H. E. Nuttall ◽  
T. L. Cook ◽  
R. S. Rundberg
Keyword(s):  
Numerical Simulation ◽  
Heat Flow ◽  
Radioactive Waste ◽  
Numerical Models ◽  
Test Site ◽  
Yucca Mountain ◽  
Nevada Test Site ◽  
Flow And Transport ◽  
Geologic Storage ◽  
High Level

ABSTRACTThe unsaturated, fractured tuff of Yucca Mountain in the Nevada Test Site is one of the potential sites for geologic storage of high-level radioactive waste. A modeling study of flow and transport in this geologically complex site is presented. Numerical models of mass and heat flow in conjunction with analytical solutions are being used for sensitivity and pathway analysis studies and to aid in design and interpretation of laboratory and field flow and transport tests in tuff.

Modeling Geochemical Stability of Cement Formulations for use as Shaft Liner and Sealing Components at Yucca Mountain(1)

1990 ◽  
Vol 212 ◽  
Author(s):  
Mark A. Gardiner ◽  
Thomas E. Hinkebein ◽  
Jonathan Myers
Keyword(s):  
Ground Water ◽  
Nuclear Waste ◽  
Geochemical Modeling ◽  
Cementitious Materials ◽  
Yucca Mountain ◽  
Nuclear Waste Repository ◽  
Preliminary Estimate ◽  
Mountain Site ◽  
Compositional Changes ◽  
Waste Repository

ABSTRACTThe geochemical modeling codes EQ3NR/EQ6 were used to model the interaction of cementitious materials with ground water from the Yucca Mountain proposed nuclear waste repository site in Nevada. This paper presents a preliminary estimate of the compositional changes caused by these interactions in the ground water and in the cement-based compounds proposed for use as sealing and shaft liner materials at the Yucca Mountain site.

scholarly journals Insights to Repository Performance through Study of a Nuclear Test Site

2000 ◽  
Vol 663 ◽  
Author(s):  
D.K. Smith ◽  
A.B. Kersting ◽  
J.L. Thompson ◽  
D.L. Finnegan
Keyword(s):  
Tectonic Setting ◽  
Test Site ◽  
Yucca Mountain ◽  
Nuclear Test ◽  
High Level Waste ◽  
Radionuclide Transport ◽  
Source Terms ◽  
Nevada Test Site ◽  
Waste Repository ◽  
High Level

ABSTRACTUnderground nuclear test sites offer an unprecedented opportunity to evaluate processes relevant to high-level waste repository performance in the absence of engineered barriers. Radionuclide migration programs at the Nevada Test Site represent a twenty-five year systematic investigation of the diverse radiologic source terms residual from weapons testing and the evolution of the hydrologic source term which comprises those radionuclides dissolved in or otherwise available for transport by groundwater. The Nevada Test Site shares actinide source terms, correlative geology, an identical tectonic setting, similar climate, and a thick unsaturated zone with the adjacent potential Yucca Mountain high-level waste repository and provides a natural laboratory to assess long-term radionuclide transport in the near field. Analog studies may ultimately help validate predictions of radionuclide transport from the potential Yucca Mountain repository.

Conductivity Behavior of Salt Deposits on the Surface of Engineered Barrier Materials for the Potential High-Level Nuclear Waste Repository at Yucca Mountain, Nevada

2004 ◽  
Vol 824 ◽  
Author(s):  
Lietai Yang ◽  
Miriam R. Juckett ◽  
Roberto T. Pabalan
Keyword(s):  
Electrical Conductance ◽  
Yucca Mountain ◽  
Nuclear Waste Repository ◽  
Conductivity Measurements ◽  
Barrier Materials ◽  
Salt Mixtures ◽  
High Level Nuclear Waste ◽  
Waste Repository ◽  
High Level ◽  
Conductivity Behavior

AbstractThe electrical conductance or conductivity of three salt mixtures, Na-K-Cl-NO3, Ca-K-Cl and Ca-Na-Cl, were measured at 25, 50 and 70°C [77, 122, and 158 °F] as a function of relative humidity (RH). Mutual deliquescence and efflorescence RH (MDRH and MERH) values were determined based on the conductivity measurements. It was found that the conductivity of the three salt mixtures started to increase at RH values that are approximately 40 % of their MDRH and increased by 1to 2 orders of magnitude just before reaching the MDRH. At the MDRH, a significant increase in conductivity was observed. The MDRH and MERH for the Ca-K-Cl and Ca-Na-Cl mixtures were found to be approximately 15 % in the temperature range of 50 to 70 °C [122 to 158 °F]. The MDRH and MERH for the Na-K-Cl-NO3system were found to be approximately 54 % at 50 °C [122 °F] and decreased significantly with an increase in temperature.

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.

Microearthquakes at Yucca Mountain, Nevada

1992 ◽  
Vol 82 (1) ◽  
pp. 164-174
Author(s):  
James N. Brune ◽  
Walter Nicks ◽  
Arturo Aburto
Keyword(s):  
Great Basin ◽  
Narrow Band ◽  
High Gain ◽  
Yucca Mountain ◽  
Continuous Operation ◽  
Nuclear Waste Repository ◽  
High Level Nuclear Waste ◽  
Waste Repository ◽  
High Level ◽  
Approximate Magnitude

Abstract We operated a microearthquake array in the neighborhood of the proposed high-level nuclear waste repository at Yucca Mountain, Nevada. The array consists of four high-gain (up to 34 million), narrow band (25 Hz) telemetered stations. Based on approximate magnitude calibration of the array we expect during quiet periods, for distances less than 15 km, complete recording of events at Yucca Mt. for M ≧ −1. We have operated the four stations for 12-hour periods overnight between August and October 1990 and intermittently afterward, until April 1991, when we began more or less continuous operation. The pattern of microearthquake activity confirms the existence of a zone of seismic quiescence in the vicinity of proposed repository. We recorded only about 10 events with S-P times of less than 3 sec (D < 24 km). Most events had S-P times between 3 and 6.5 sec, consistent with the higher seismic activity at distances between 24 and 52 km observed by Rogers et al. (1987) and Gomberg (1991). Oliver et al. (1966) found, contrary to what has been observed by us for Yucca Mountain, that in seismically active areas most of the events had S-P times of less than 3 sec. We confirmed this expectation for four microearthquake stations near Mammoth Lakes, where we observed microearthquake rates of over 100 per day, most with S-P times of less than 3 sec. Extrapolation of seismicity data from the Southern Great Basin Seismic Network confirms the low microearthquake activity in the immediate vicinity of Yucca Mountain.

Sensitivity to Formation Porosity of Contaminant Transport from Nevada Test Site to Yucca Mountain

2011 ◽  
Vol 15 (4) ◽  
pp. 219-227 ◽  
Author(s):  
Jianting Zhu ◽  
Karl F. Pohlmann ◽  
Jenny B. Chapman ◽  
Charles E. Russell ◽  
Rosemary W. H. Carroll ◽  
...  
Keyword(s):  
Contaminant Transport ◽  
Test Site ◽  
Yucca Mountain ◽  
Nevada Test Site ◽  
Formation Porosity

scholarly journals Radionuclides in Hydrothermal Systems as Indicators of Repository Conditions

1990 ◽  
Vol 212 ◽  
Author(s):  
H.A. Wollenberg ◽  
S. Flexser ◽  
A.R. Smith
Keyword(s):  
Sedimentary Rocks ◽  
Carbonaceous Material ◽  
Test Site ◽  
Volcanic Field ◽  
Yucca Mountain ◽  
Hydrothermal Systems ◽  
Rock Matrix ◽  
Nevada Test Site ◽  
San Juan Mountains ◽  
Long Valley

ABSTRACTHydrothermal systems in tuffaceous and older sedimentary rocks contain evidence of the interaction of radionuclides in fluids with rock matrix minerals and with materials lining fractures, in settings somewhat analogous to the candidate repository site at Yucca Mountain, NV. Earlier studies encompassed the occurrences of U and Th in a “fossil” hydrothermal system in tuffaceous rock of the San Juan Mountains volcanic field, CO. More recent and ongoing studies examine active hydrothermal systems in calderas at Long Valley, CA and Valles, NM. At the Nevada Test Site, occurrences of U and Th in fractured and unfractured rhyolitic tuff that was heated to simulate the introduction of radioactive waste are also under investigation. Observations to date suggest that U is mobile in hydrothermal systems, but that localized reducing environments provided by Fe-rich minerals and/or carbonaceous material concentrate U and thus attenuate its migration.

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