november 7, 2004 gsa annual meeting, denver, co russell l jarek, carlos f. jove-colon and charles r....
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November 7, 2004
GSA Annual Meeting, Denver, CO
Russell L Jarek, Carlos F. Jove-Colon andCharles R. Bryan
Sandia National LabsAlbuquerque, New Mexico
Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company,for the United States Department of Energy’s National Nuclear Security Administration
under contract DE-AC04-94AL85000.
In-Drift Chemical Modeling – From Data to Abstraction
Measurement and Test Data
Drift-Scale THC Physical & ChemicalEnvironment Models
Stratigraphy,Mineralogy
Repository Horizon Pore Water Chemistry
USGS: In-Drift Dust Leachate Chemistry
Multiscale TH
Overview from Data to Performance Assessment
Rock Thermal Properties
Measurement and Test Data
Multiscale TH Drift-Scale THC Physical & ChemicalEnvironment Models
EQ 3/6 with Pitzer Database
Potential Seepage Compositions
For Evaporative Evolution to Brine
Overview from Data to Performance Assessment
Measurement and Test Data
Multiscale TH Drift-Scale THC Physical & ChemicalEnvironment Models
EQ 3/6 with Pitzer Database
PA for License Application: Drip Shield and Waste Package DegradationWaste Form Degradation and Mobilization
· In-Drift Temperatures
· Relative Humidities
Local Chemical Environment (pH, I, [Cl−], [NO3
−])
Overview from Data to Performance Assessment
Drift-Scale THC Physical & ChemicalEnvironment Models
EQ 3/6 with Pitzer Database
Focus of In-Drift Details
Potential Seepage Compositions
Measurement and Test Data
Repository Horizon Pore Water Chemistry
PA for License Application: Drip Shield and Waste Package DegradationWaste Form Degradation and Mobilization
Yucca Mountain Pore Waters
5 Pore Waters Chosen to carry forward in THC analysis.
Ca + M
gSO4 +
Cl
Mg
Na+KCa CO3 Cl
SO4
• Units of % meq/l
THC Potential Seepage Outputs
• Fracture Chemistries used for Crown Seepage– Evolution of parameters from starting pore waters
• P(CO2), pH, Na, K, Ca, Mg, SiO2, HCO3, Cl, NO3, F, SO4
• Al and Fe included from illite and hematite equilibrium
Drift-Scale THC Physical & ChemicalEnvironment Models
EQ 3/6 with Pitzer Database
Local Chemical Environment (pH, I, P(CO2), [Cl−], [NO3
−])
Focus of In-Drift Details
For Evaporative Evolution to Brine
Measurement and Test Data
PA for License Application: Drip Shield and Waste Package DegradationWaste Form Degradation and Mobilization
EQ3/6 Results with Pitzer Database
Compared with CRC Handbook data (81th ed., 2000) at 100ºC.
0
0.2
0.4
0.6
0.8
1
0 0.2 0.4 0.6 0.8 1
Activity of Water
mas
s so
lute
/(m
ass
solu
te +
mas
s H
2O
1:1 MgCl2 + CaCl2
EQ3/6 (version 8.0)with new Pitzer DB
1:1 NaNO3 + Ca(NO3)2
1:1 CaCl2 + Ca(NO3)2
Scanning Electrodynamic Balance Experimental Data (evaporation): Choi and Chan (2002)
Compared with evaporation experimental data for prediction of aw.
Saturated Solutions Evaporation of Mixtures
•Do have problems with KNO3 at high temp. ORNL (D. Palmer) will conduct isopiestic experiments.
Na-Cl-Al(OH)4-SiO2-OH-Mg-NO3-Ca-SO4-H2O system; 25 to 140 C.
Example of Seepage Evaporation Result
Evolution to a Na/K-Cl/NO3 brine.
Minerals:Calcite, Halite, Fluorite, Amorphous Si, Thenardite, Nitrite, other minor.
Seepage Abstraction
• Take the THC Chemistry vs. Time Information
– Evaporate one water from each time step to 65% RH• This passes most chemical divides and reaches halite
– Group resulting water chemistries according to their aqueous compositions (results in 11 “bins”)
– The representative water for each bin is used in place of all the other waters from that bin
Condition-Dependent Chemistry for PA
• Abstraction Allows for Condition-Dependent Chemical Representation– For each of the representative bin seepage waters:
• 3 Temperatures (40, 70, 100°C)
• 3 P(CO2) (10−2, 10−3, 10−4 bars)
• 2% RH increments, or less
– 99 Tables for TSPA-LA to sample from
• Outputs that feed directly to TSPA-LA
– Waste Package Degradation (Localized Corrosion)• Seepage chemistry parameters (P(CO2), pH, Cl, NO3)
• Dust deliquescence (P(CO2), pH, Cl, NO3)
– Waste Form Degradation and Mobilization• Invert chemistry parameters (pH, ionic strength)
In-Drift Physical and Chemical Environment
• Importance of In-Drift Water / Gas Chemistry in PA– Determining factor for potential localized corrosion
of waste packages
– Can affect invert radionuclide solubility
• Many Models and Data Contribute– Pore water and dust leachate analyses
– Drift-Scale Thermohydrologic Chemical Model to obtain starting composition and CO2(g)
– Pitzer database and EQ3/6 to evolve T and RH conditions
Summary
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