In the 1960s and 1970s, DOE and its predecessor agencies experimented with using nuclear devices to fracture and stimulation natural gas production from low permeability rocks. Among these tests was Project Rulison in Colorado where a nuclear device was detonated 2,568 m below the surface. While for many years the depth of the test offered protection to receptors from the subsurface radionuclides, today this part of western Colorado is a major production area for natural gas. In addition, a common technique now being used to increase natural gas production is "hydrofracturing", where water, slurry, or chemicals are injected under high pressure to create fractures that increases the flow of gas. At Project Rulison, the concern now is whether tritium from the underground nuclear tests could migrate to the surface because of intersecting fractures from the nuclear tests and natural gas production. DRI is estimating tritium travel distance in both gas and liquid phases using the numerical simulator TOUGH2. Modeling has been done under current conditions as well as with hypothetical gas well production where transport is enhanced by a pressure gradient produced by it. Results of the research will be used to establish a zone around the Project Rulison site where new natural gas wells will be restricted. However, even with the modeling, there is considerable uncertainty because of the complex interbedding of sandstone and shale at depth, and the location, length, and permeability of fractures.

DRI is performing the work as a subcontractor to S.M. Stoller for the DOE Office of Legacy Management (OLM). Project Rulison is one of eight "Off-Site Test Areas," continental locations off the Nevada National Security Site where underground nuclear tests were conducted. DRI researchers have been involved in subsurface characterization and contaminant transport modeling at seven of these sites.

Rulison is one of eight "offsite" tests areas in five states, where underground nuclear tests were conducted off the Nevada Nuclear Security Site.

Jenny Chapman, and personnel from the Nevada Division of Environmental Protection at the Central Nevada Test Area (CNTA), one of two "Offsite Test Areas" in Nevada.