Transport modeling in a finite fractured rock domain
The Waste Isolation Pilot Plant (WIPP) is a US Department of Energy facility intended to demonstrate the safe disposal of transuranic nuclear waste. The WIPP is located in the thick halite beds of the Salado Formation in the Delaware Basis of southeastern New Mexico. Overlying the repository is the Culebra Dolomite Member of the Rustler Formation, a dolomitic unit containing accessory minerals such as calcite, gypsum, and clays. The Culebra is the predominant continuous water-bearing unit in the area. Part of the scientific demonstration of the safety of WIPP involves understanding and predicting what might happen should the WIPP be intruded by boreholes during exploration for natural resources long after the WIPP has been decommissioned. Should such a breach occur, it is possible that dissolved transuranic waste could be transported up a borehole and into the Culebra, through which it could eventually reach the accessible environment. The rates and mechanisms for actinide transport in Culebra Dolomite are being investigated as a component of repository performance assessment. Numerical simulations with the FMT (Fracture Matrix Transport) finite difference model in a finite, idealized double porosity system were performed to: (1) delineate parameter values for which a set of two coupled one-dimensional equations is insufficient to describe behavior and a fully two-dimensional representation is needed, (2) compare chemical retardation by ion exchange for fractures with and without a clay lining, and (3) compare physical and chemical retardation by ion exchange as a function of fracture velocity. The simulations differ from others in that the matrix is finite, and thus can become saturated with tracers introduced into the domain. The modeling suggests that the chemical retardation caused by clay linings may not be important in a double porosity system. Over a wide range, a single parameter group essentially determines the complexity of the model.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (United States)
- Sponsoring Organization:
- DOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 7005141
- Report Number(s):
- SAND-92-0936C; CONF-921101--2; ON: DE92040965
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
54 ENVIRONMENTAL SCIENCES
540230 -- Environment
Terrestrial-- Radioactive Materials Monitoring & Transport-- (1990-)
ALPHA-BEARING WASTES
COMPUTERIZED SIMULATION
ENVIRONMENTAL TRANSPORT
FUNCTIONAL MODELS
MASS TRANSFER
MATERIALS
NATIONAL ORGANIZATIONS
NUCLEAR FACILITIES
PILOT PLANTS
POROSITY
RADIOACTIVE MATERIALS
RADIOACTIVE WASTE FACILITIES
RADIOACTIVE WASTES
RADIONUCLIDE MIGRATION
ROCKS
SIMULATION
TWO-DIMENSIONAL CALCULATIONS
UNDERGROUND FACILITIES
US DOE
US ORGANIZATIONS
WASTES
WIPP