On October 26, 1963, the Department of Defense (DoD) and the Atomic Energy Commission (AEC) (now known as the U. S. Department of Energy (DOE)) detonated a nuclear device with a total yield of 12 kilotons at a depth of 1,204 feet below ground surface in the solid granite of the Sand Springs Range southeast of Fallon, Nevada.
Radiological contamination of groundwater resulted from the test. Today, scientists and engineers, contracted by DOE, are working to identify the risks where radiological contamination exists in groundwater, predict the movement of the contaminated groundwater, and define the extent of migration of the radionuclides released during testing.
The Nevada Division of Environmental Protection (NDEP) Bureau of Federal Facilities provides programmatic and regulatory oversight of federal facilities, including both U. S. Department of Energy (DOE) and U. S. Department of Defense (DoD) facilities, in Nevada.
The Federal Facility Agreement and Consent Order (FFACO), outlines a process to insure that the DOE and/or the DoD, under the regulatory authority and oversight of the NDEP, identify sites of potential historic contamination, thoroughly investigate these sites, and implement corrective actions based on public health and environmental considerations.
The FFACO specifically covers the following federal facilities in Nevada: the Nevada Test Site (NTS), the Tonopah Test Range (TTR), the Nellis Air Force Range (NAFR), the Central Nevada Test Area (CNTA), and the Project Shoal Area (PSA).
For purposes of investigation and corrective action implementation, the Project Shoal Area and the Central Nevada Test Area are grouped as the Nevada Off-Sites. Each of these two sites is considered a separate Corrective Action Unit (CAU) based on geographic location.
This website has been developed by NDEP to improve public access to regulatory and programmatic information at the Project Shoal Area, Nevada. The PSA is located approximately 28 miles southeast of Fallon, in the Sand Springs Range in Churchill County, Nevada. Access is via U. S. Highway 50, Nevada Highway 839, and an improved gravel road into the site.
The Vela Uniform program began in 1959 and was part of a Department of Defense (DoD) research and development program intended to improve the capability of detecting, monitoring, and identifying underground and high-altitude nuclear detonations. Project SHOAL was an underground nuclear test conducted jointly by the DoD and the Atomic Energy Commission (AEC). Part of the Vela Uniform program, it was designed to investigate the behavior and characteristics of seismic signals generated by a nuclear detonation in a granite rock formation and to differentiate them from seismic signals generated by naturally occurring earthquakes.
The 4-square mile area of land around the designated test location was withdrawn by the Bureau of Land Management (BLM) from public domain by Public Land Order 2771 issued on September 6, 1962, as amended by Public Land Order 2834 and assigned to the exclusive use of the AEC. The device, emplaced at a depth of 1,205 feet below ground surface and at the end of a 1050-foot drift - (Diagram) mined east from the vertical shaft, was detonated on October 26, 1963. The nuclear test created a cavity with an approximate diameter of 171 feet which subsequently collapsed and formed a rubble-filled chimney 356 feet high. The chimney did not propagate to the land surface and no surface crater was formed.
The PSA is no longer in use for testing purposes. Custody of the site was turned over to the Navy in 1970 and access to the area is currently unrestricted.
Two Corrective Action Units (CAUs) were identified for the PSA in the FFACO: 1) CAU 416 - PSA Surface, and 2) CAU 447 - PSA Subsurface. The selection of corrective action processes for both surface and subsurface contamination is based on site-specific information and conditions.
While no surface contaminant exists today, there is radioactive contamination of the deep granitic rock around the shot cavity. Groundwater is the most likely transport medium for this contamination, however, because of the depth of the contamination (approximately 1,204 feet) and the remoteness of the site, exposure to humans is unlikely. Characterization of the hydrogeologic conditions at the PSA is being conducted by the U.S. Department of Energy (DOE) and its contractors.
The strategy for the subsurface is to characterize groundwater flow and contaminant transport through numerical modeling utilizing site-specific hydrologic data. The contaminant of focus is tritium, because, based on presently available data, it is the most conservative (i.e., remains in solution) and therefore the most mobile of the potential radiological contaminants.
The hydrologic boundaries will define the area in which contaminants are expected to remain. It is anticipated that after boundaries have been established a determination can be made that monitoring alone will be acceptable and some form of active contaminant containment system will not be necessary.
The links at the bottom of the page provide more details about ongoing remediation activities at the PSA. For additional information contact Christine Andres, Nevada Division of Environmental Protection - Bureau of Federal Facilities