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U.S. Department of Energy
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Technical basis for a conceptual model in unsaturated tuff for the NEFTRAN-S code

Technical Report ·
OSTI ID:138137

NEFTRAN-S was developed by Sandia National Laboratories for the United States Environmental Protection Agency as part of a program providing technical support for re-promulgation of the standard 40 CFR 191. The code is intended to provide realistic estimates of releases to the environment that could result from disposal of radioactive waste in geologic subsurfaces. One of the geologic environments that will be considered by the EPA in their analyses is unsaturated tuff. The information given in this report is intended to provide a conceptual model for the NEFTRAN-S code for calculations involving a generic site in unsaturated tuff. Information about the phenomena expected to dominate transport and methods for modeling transport in an unsaturated medium are presented. NEFTRAN-S calculations using this conceptual model are compared to TOSPAC calculations for three possible infiltration rates. TOSPAC is the code currently used in performance assessment for an unsaturated tuff site at Yucca Mountain in Nevada. 14 refs., 21 figs., 22 tabs.

Research Organization:
Sandia National Labs., Albuquerque, NM (United States)
Sponsoring Organization:
USDOE, Washington, DC (USA)
DOE Contract Number:
AC04-76DP00789
OSTI ID:
138137
Report Number(s):
SAND--90-1986; ON: DE91014717
Country of Publication:
United States
Language:
English