Modification of the finite element heat and mass transfer code (FEHM) to model multicomponent reactive transport
The finite element code FEHMN, developed by scientists at Los Alamos National Laboratory (LANL), is a three-dimensional finite element heat and mass transport simulator that can handle complex stratigraphy and nonlinear processes such as vadose zone flow, heat flow and solute transport. Scientists at LANL have been developing hydrologic flow and transport models of the Yucca Mountain site using FEHMN. Previous FEHMN simulations have used an equivalent Kd model to model solute transport. In this thesis, FEHMN is modified making it possible to simulate the transport of a species with a rigorous chemical model. Including the rigorous chemical equations into FEHMN simulations should provide for more representative transport models for highly reactive chemical species. A fully kinetic formulation is chosen for the FEHMN reactive transport model. Several methods are available to computationally implement a fully kinetic formulation. Different numerical algorithms are investigated in order to optimize computational efficiency and memory requirements of the reactive transport model. The best algorithm of those investigated is then incorporated into FEHMN. The algorithm chosen requires for the user to place strongly coupled species into groups which are then solved for simultaneously using FEHMN. The complete reactive transport model is verified over a wide variety of problems and is shown to be working properly. The new chemical capabilities of FEHMN are illustrated by using Los Alamos National Laboratory`s site scale model of Yucca Mountain to model two-dimensional, vadose zone {sup 14}C transport. The simulations demonstrate that gas flow and carbonate chemistry can significantly affect {sup 14}C transport at Yucca Mountain. The simulations also prove that the new capabilities of FEHMN can be used to refine and buttress already existing Yucca Mountain radionuclide transport studies.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 279704
- Report Number(s):
- LA-13167-T; ON: DE96014319; TRN: 96:024867
- Resource Relation:
- Other Information: PBD: Aug 1996
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
99 MATHEMATICS
COMPUTERS
INFORMATION SCIENCE
MANAGEMENT
LAW
MISCELLANEOUS
RADIOACTIVE WASTE FACILITIES
SITE CHARACTERIZATION
HIGH-LEVEL RADIOACTIVE WASTES
UNDERGROUND DISPOSAL
RADIONUCLIDE MIGRATION
F CODES
TUFF
GROUND WATER
ALGORITHMS
GAS FLOW
MASS TRANSFER
STRATIGRAPHY
YUCCA MOUNTAIN
FINITE ELEMENT METHOD
HEAT TRANSFER
CARBON 14