In-Drift Chemical Modeling – From Data to Abstraction :
November 7, 2004
GSA Annual Meeting, Denver, CO
Russell L Jarek, Carlos F. Jove-Colon and Charles R. Bryan
Sandia National Labs
Albuquerque, 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
Overview of In-Drift Environment : Overview of In-Drift Environment
Overview from Data to Performance Assessment : Measurement and Test Data Drift-Scale THC Physical & Chemical Environment 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
Slide4 : Measurement and Test Data Multiscale TH Drift-Scale THC Physical & Chemical Environment Models EQ 3/6 with Pitzer Database Potential Seepage Compositions For Evaporative Evolution to Brine Overview from Data to Performance Assessment
Slide5 : Measurement and Test Data Multiscale TH Drift-Scale THC Physical & Chemical Environment Models EQ 3/6 with Pitzer Database · In-Drift Temperatures · Relative Humidities Local Chemical Environment (pH, I, [Cl−], [NO3−]) Overview from Data to Performance Assessment
Slide6 : Drift-Scale THC Physical & Chemical Environment Models EQ 3/6 with Pitzer Database Focus of In-Drift Details Potential Seepage Compositions Measurement and Test Data Repository Horizon Pore Water Chemistry
Yucca Mountain Pore Waters : Yucca Mountain Pore Waters 5 Pore Waters Chosen to carry forward in THC analysis. Ca + Mg SO4 + Cl Mg Na+K Ca CO3 Cl SO4 Units of % meq/l
Drift-Scale Thermohydrologic-Chemical Processes Modeled : Drift-Scale Thermohydrologic-Chemical Processes Modeled Illustration; not to scale.
Slide9 : THC Results at Repository Drift Horizon
THC Potential Seepage Outputs : 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
Slide11 : Drift-Scale THC Physical & Chemical Environment 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
EQ3/6 Results with Pitzer Database : EQ3/6 Results with Pitzer Database Compared with CRC Handbook data (81th ed., 2000) at 100ºC. 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.
Evaporation and Deliquescence Processes : Evaporation and Deliquescence Processes
Example of Seepage Evaporation Result : 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 : 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
Slide16 : Representative Seepage Bin Compositions
Condition-Dependent Chemistry for PA : 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
Bin-History Map : Bin-History Map
In-Drift Physical and Chemical Environment : 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
Summary : 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
Acknowledgements : Acknowledgements THC Model:
Nicholas Spycher (LBNL)
Eric Sonnenthal (LBNL)
EQ3/6 Pitzer Database:
Tom Wolery (LLNL)
Additional Thanks:
Paul Mariner (Framatome)
Ernest Hardin (BSC)
Cliff Howard (SNL)
Darren Jolley