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Title: Thermal conductivity of silicic tuffs: predictive formalism and comparison with preliminary experimental results

Technical Report ·
DOI:https://doi.org/10.2172/59407· OSTI ID:59407

Performance of both near- and far-field thermomechanical calculations to assess the feasibility of waste disposal in silicic tuffs requires a formalism for predicting thermal conductivity of a broad range of tuffs. This report summarizes the available thermal conductivity data for silicate phases that occur in tuffs and describes several grain-density and conductivity trends which may be expected to result from post-emplacement alteration. A bounding curve is drawn that predicts the minimum theoretical matrix (zero-porosity) conductivity for most tuffs as a function of grain density. Comparison of experimental results with this curve shows that experimental conductivities are consistently lower at any given grain density. Use of the lowered bounding curve and an effective gas conductivity of 0.12 W/m{sup 0}C allows conservative prediction of conductivity for a broad range of tuff types. For the samples measured here, use of the predictive curve allows estimation of conductivity to within 15% or better, with one exception. Application and possible improvement of the formalism are also discussed.

Research Organization:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Organization:
USDOE
DOE Contract Number:
AC04-76DP00789
OSTI ID:
59407
Report Number(s):
SAND-80-0769; ON: RECYCLE
Resource Relation:
Other Information: PBD: Jul 1980
Country of Publication:
United States
Language:
English