Abstract:Laboratory experiments were performed to investigate the effects of spatial variation in porosity on matrix-diffusion processes. Four centimeter-scale slabs of Culebra dolomite taken from the Waste 'Isolation Pilot Plant site were used in the tests. Experiments involved the simple diffusion of iodine into a single edge of each rock slab while X ray absorption imaging was used to measure the resulting two-dimensional solute concentration field as a function of time. X ray imaging was also used to quantify the two-dimensional porosity field of each rock slab. Image analysis provided a unique opportunity to both visualize and quantify the effects of the spatially variable porosity on matrixdiffusion. Four key results were obtained. First, significant variation in rates of diffusion were realized over the relatively small length (centimeter) and time scales (months) investigated. Second, clear evidence of diffusion preferentially following zones of relatively higher porosity was noted. Third, rate of diffusion was found to vary as tracer diffused into the rock slabs encountering changing porosity conditions. Fourth, strong correlation between porosity and the calculated diffusion coefficients was found. In fact, the nature of the correlation can be related to the geometry, position, and orientation of the heterogeneous porosity features populating each rock slab.

A hydrologic modeling study was performed to gain insight into the flow mechanisms around Room Q. A summary of hydrologic and structural data and of predictive fluid flow models from Room Q are provided. Six years of measured data are available from the time of excavation. No brine accumulation in Room Q was measured in the first two years following excavation. However, there is considerable uncertainty associated with this early-time data due to inadequate sealing of the room. Brine may have been lost to evaporation or it may have flowed into newly created disturbed rock zone (DRZ) porosity resulting from excavation. Non-zero brine accumulation rates were measured from 2-5 years, but brine accumulation within the room dropped to zero after 5.5 years. A conceptual model for brine inflow to Room Q was developed which assumes far-field Darcy flow combined with an increasing DRZ pore volume. Numerical simulations employed TOUGH28W and used predictive DRZ porosity increase with time from SPECTROM-32 rock deformation simulations. Simulated brine inflow showed good agreement with measured brine accumulation rates for the first five years. Two important conclusions were drawn fiom the simulation results: (1) early-time brine inflow to the room can be reduced to zero if the DRZ pore volume increases with time, and (2) brine accumulation (inflow) rates fiom 2 to 5 years suggest a far-field permeability of 5 x m2 with a bulk rock compressibility of 5.4 x 10-I2 Pa-I. The early-time brine inflow to the DISCLAIMER This report was prepared as a n account of work sponsored by a n agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disdased, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or sern'ce by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necesSarily state or reflect those of the United States Government or any agency thereof.. Greg Ruskauff of INTERA Inc. for performing many of the TOUGH28W numerical simulations; Kerry DeVries of RE/SPEC Inc. for his time and efforts providing results from SPECTROM-32 simulations; Rick Bower of TechReps Inc. for providing Room Q data;

Sandia National Laboratories maintains several libraries of equation of state tables, in a modified Sesame format, for use in hydrocode calculations and other applications. This report discusses one of those libraries, the seslan file, which contains 78 tables from the Los Alamos equation of state library. Minor changes have been made to these tables, making them more convenient for code users and reducing numerical difficulties that occasionally arise in hydrocode calculations. MA,STEB DItBTI_BUTION OF THIS DOCUMENT IS UNLIMITED Sandia EOS Data Base Contents Seslan File Appendix: File seslan.ref DOCUMF_PPATION OF DATA ON SANDIA SESLAN LIBRARY FILE Gerald I. Kerley, Division 1432 " 05/03/93 The seslan file contains Sesame EOS tables taken from the Los Alamos • data base. The 201 table was modified to give a reference state for use in hydro calculations. In some cases, the PANDA code was used to add points at zero density and temperature and to modify the pressure and energy in the tension region. 78 Materials on File .... Reference State Properties .... Material Material Density Temperature Sound Speed Table Name Number (g/cc) (Kelvin) (km/s) Types Uranium 1540 18.813

The PANDA code is used to construct tabular equations of state (EOS) for the detonation products of 24 explosives having CHNO compositions. These EOS, together with a reactive bum model, are used in numerical hydrocode calculations of cylinder tests. The predicted detonation properties and cylinder wall velocities are found to give very good agreement with experimental data. Calculations of flat plate acceleration tests for the HMX-based explosive LX14 are also made and shown to agree well with the measurements. The effects of the reaction zone on both the cylinder and flat plate tests are dkcussed. For TATB-based explosives, the differences between experiment and theory are consistently larger than for other compositions and may be due to nonideal (finite diameter) behavior.

Approved for public releaa&hIatribution la unlimited.