Numerical models Drift Scale Test

Sonnenthal, E. L., N. F. Spycher, M. E. Conrad, and J. A. Apps, 2003. A Conceptual and Numerical Model for Thermal-hydrologic-chemical Processes in the Yucca Mountain Drift Scale Test. Proceedings (to be published). GeoProc2003, Stockholm, Sweden, October 2003. 

Abstract As a part of the DECOVALEX 111 project—model predictions were carried out of thermomechanical (TM) rock-mass responses at the Yucca Mountain drift scale test (DST), Nevada. This paper presents model predictions of TM-induced rock displacements at the DST carried out by two independent research teams using two different approaches and two different numerical models. Displacements predicted by the two independent analyses compare reasonably well to the measured ones, both in trends and average magnitude. The analyses indicate that the rock mass behaviour is essentially elastic and that the in situ rock mass thermal expansion coefficient is well represented a temperature-dependent thermal-expansion derived from laboratory tests on intact rock. 

A CONCEPTUAL AND NUMERICAL MODEL FOR THERMAL-HYDROLOGICAL-CHEMICAL PROCESSES IN THE YUCCA MOUNTAIN DRIFT SCALE TEST... 

Abstract Results from the four-year long heating phase of the Drift-Scale Heater Test at the Exploratory Studies Facility at Yucca Mountain, Nevada, provide a basis to evaluate conceptual and numerical models used to simulate thermal-hydrological coupled processes expected to occur at the proposed repository. A three-dimensional numerical model was built to perform the analyses. All model simulations were predicated on a dual (fracture and matrix) continuum conceptualization. A 20-percent reduction in the canister heat load to account for conduction and radiation heat loss through the bulkhead, a constant pressure boundary condition at the drift wall, and inclusion of the active fracture model to account for a reduction in the number of fractures that were hydraulically active provided the best agreement between model results and observed temperatures. The views expressed herein are preliminary and do not constitute a final judgment of the matter addressed or of the acceptability of its use in a license application... 

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