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-AC04-94AL In-Drift Chemical Modeling – From Data to Abstraction

Overview of In-Drift Environment

Measurement and Test Data Drift-Scale THCPhysical & 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

Measurement and Test Data Multiscale THDrift-Scale THCPhysical & Chemical Environment 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 THDrift-Scale THCPhysical & Chemical Environment Models EQ 3/6 with Pitzer Database PA for License Application: Drip Shield and Waste Package Degradation Waste Form Degradation and Mobilization · In-Drift Temperatures · Relative Humidities Local Chemical Environment (pH, I, [Cl − ], [NO 3 − ]) Overview from Data to Performance Assessment

Drift-Scale THCPhysical & 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 PA for License Application: Drip Shield and Waste Package Degradation Waste Form Degradation and Mobilization

Yucca Mountain Pore Waters 5 Pore Waters Chosen to carry forward in THC analysis. Ca + Mg SO 4 + Cl Mg Na+K Ca CO 3 Cl SO 4 Units of % meq/l

Drift-Scale Thermohydrologic-Chemical Processes Modeled Illustration; not to scale.

THC Results at Repository Drift Horizon

THC Potential Seepage Outputs Fracture Chemistries used for Crown Seepage –Evolution of parameters from starting pore waters P(CO 2 ), pH, Na, K, Ca, Mg, SiO 2, HCO 3, Cl, NO 3, F, SO 4 Al and Fe included from illite and hematite equilibrium

Drift-Scale THCPhysical & Chemical Environment Models EQ 3/6 with Pitzer Database Local Chemical Environment (pH, I, P(CO 2 ), [Cl − ], [NO 3 − ]) Focus of In-Drift Details For Evaporative Evolution to Brine Measurement and Test Data PA for License Application: Drip Shield and Waste Package Degradation Waste Form Degradation and Mobilization

EQ3/6 Results with Pitzer Database Compared with CRC Handbook data (81 th ed., 2000) at 100ºC. Compared with evaporation experimental data for prediction of a w. Saturated Solutions Evaporation of Mixtures Do have problems with KNO 3 at high temp. ORNL (D. Palmer) will conduct isopiestic experiments. Na-Cl-Al(OH) 4 -SiO 2 -OH-Mg-NO 3 -Ca-SO 4 -H 2 O system; 25 to 140  C.

Evaporation and Deliquescence Processes

Example of Seepage Evaporation Result Evolution to a Na/K-Cl/NO 3 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

Representative Seepage Bin Compositions

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(CO 2 ) (10 −2, 10 −3, 10 −4 bars) 2% RH increments, or less –99 Tables for TSPA-LA to sample from

Bin-History Map

Outputs that feed directly to TSPA-LA –Waste Package Degradation (Localized Corrosion) Seepage chemistry parameters (P(CO 2 ), pH, Cl, NO 3 ) Dust deliquescence (P(CO 2 ), pH, Cl, NO 3 ) –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 CO 2 (g) –Pitzer database and EQ3/6 to evolve T and RH conditions Summary

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