homogeneous medium with no heat loss. The results predict that after 21 days a volume of approxi-
mately 1,000 cubic feet will be heated to a temperature in excess of 100°C.

The field test includes three sepa-
rate operations: (1) a "cold" pump test to establish a baseline per-
formance for the vacuum extrac-
tion system without heat ing; the duration of this test is approxi-
mately one week; (2) a heating phase with the RF hardware operation for approximately four weeks; and (3) a cool-down phase to monitor changes in offgas vent-
ing as the subsurface temperature returns to ambient.

Technology Needs

Numerous sites across the country, both commercial and within the DOE Complex, have significant levels of organic contaminants within the unsaturated soil zone. Chlorinated volatile organic sol-
vents can be held within this zone, especially in clays and organic materials. These zones slowly re-
lease the solvents and provide a long-term source for groundwater contamination. Despite the volatile nature of these contaminants, the clays severely limit the mass trans-
fer rates of the material. With this mass transfer limitation, the use of soil vacuum extraction requires a long period of operation and the