Movement of radionuclides through unsaturated soils

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5222275

de Sousa, F N.C.

The advantages of the disposal of low-level radioactive wastes in the unsaturated zone above the fluctuations of the water table have been recognized for some time. However, most the numerical models used to simulate the environmental impact of a shallow land burial site assume that the soils surrounding the waste forms are saturated; this assumption may lead, in many cases, to unrealistic large leach and water flow rates. The main purpose of this study was the development of a procedure which could give a reliable prediction on the movement of radionuclides from shallow land burial sites located in the unsaturated zone. In order to accomplish this objective three different soils having different sand, silt, and clay fractions were selected and characterized. These soils were then used to fill a number of flow columns that were used in tests designed to provide input data for the flow and transport models. A one-dimensional finite element model was developed in order to simulate the water flow and radionuclide transport through unsaturated soils. The results obtained showed that the model accurately described the transport of radionuclides through saturated-unsaturated soils. Simulations were done, for all three soils, involving different degrees of soil saturation, and the results showed that assuming the soils are always saturated may lead to nuclide transport times which are orders of magnitude larger than the real ones, depending on the clay percentage present in the soil.

• Research Organization: Georgia Inst. of Tech., Atlanta (USA)
• OSTI ID: 5222275
• Country of Publication: United States
• Language: English

Related Subjects

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12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
510301* -- Environment
Terrestrial-- Radioactive Materials Monitoring & Transport-- Soil-- (-1987)
54 ENVIRONMENTAL SCIENCES
CHEMICAL COMPOSITION
CLAYS
DISSOLUTION
ENVIRONMENTAL TRANSPORT
ISOTOPES
LEACHING
LOW-LEVEL RADIOACTIVE WASTES
MANAGEMENT
MASS TRANSFER
MATERIALS
MATHEMATICAL MODELS
RADIOACTIVE MATERIALS
RADIOACTIVE WASTE DISPOSAL
RADIOACTIVE WASTES
RADIOISOTOPES
RADIONUCLIDE MIGRATION
SAND
SEPARATION PROCESSES
SILT
SIMULATION
SOILS
UNDERGROUND DISPOSAL
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES