Project Rio Blanco

Project Rio Blanco. It was a Plowshare program experiment conducted by the United States Atomic Energy Commission in 1973, designed to test the feasibility of using multiple, simultaneously detonated nuclear devices to stimulate natural gas production from low-permeability geologic formations. The test involved the detonation of three thermonuclear devices within a single wellbore in northwestern Colorado, marking a significant and controversial chapter in the history of peaceful nuclear explosions. Its execution and aftermath intensified national debate over the environmental and economic trade-offs of such technologies.

Background and purpose

The project was a direct successor to earlier natural gas stimulation tests like Project Gasbuggy in New Mexico and Project Rulison in Colorado. These experiments, under the broader Plowshare program, aimed to develop industrial applications for nuclear explosives, a concept promoted by scientists like Edward Teller at the Lawrence Livermore National Laboratory. The specific objective was to fracture the tight, gas-bearing Williams Fork Formation of the Mesaverde Group to create an underground chimney, thereby increasing permeability and allowing commercial extraction of otherwise unrecoverable natural gas reserves. The innovation in this test was the use of three devices placed at different depths to create a larger fracture network than a single blast could achieve, a concept supported by data from prior tests like Project Gnome.

Test execution

The test was conducted on May 17, 1973, in Rio Blanco County, Colorado, approximately 55 miles northwest of Rifle. The AEC, in cooperation with private entities like CER Geonuclear Corporation, emplaced three 33-kiloton devices in a single, deeply drilled wellbore at depths of 5,838, 6,230, and 6,690 feet below the surface. Detonation was simultaneous, creating a single, rubble-filled chimney estimated to be about 400 feet in height. The event was monitored by an extensive array of seismic instruments, with data collection coordinated by agencies including the United States Geological Survey. The detonation protocol and containment measures were informed by procedures developed during the larger Operation Hardtack I and the Vela Uniform program.

Results and yield

The total explosive yield was 99 kilotons, stemming from the three individual devices. Post-detonation re-entry and evaluation, which involved drilling into the chimney region, confirmed the creation of the predicted rubble chimney. However, the quantity of natural gas stimulated was far less than anticipated, and the gas was rendered significantly radioactive due to contact with fission products, primarily tritium and krypton-85. This contamination made the gas commercially unusable without expensive and unproven cleanup processes, a problem also encountered after Project Rulison. The technical results were documented in reports to the Joint Committee on Atomic Energy and presented at symposia like the Plowshare Program Annual Meeting.

Environmental and political impact

The test provoked substantial public opposition and legal challenges from environmental groups and local citizens, concerned about radioactive contamination of groundwater and the atmosphere. The controversy occurred amidst a growing national environmental movement, following events like the Santa Barbara oil spill and influenced by legislation such as the National Environmental Policy Act. The resulting radioactive gas and seismic effects, which registered on instruments as far away as the University of California, Berkeley, fueled debate. This public and political pressure, combined with the disappointing economic results, led to increased scrutiny from congressional committees and contributed to the decline of the Plowshare program.

Legacy and significance

It represents the final natural gas stimulation experiment conducted under the Plowshare program in the United States. Its failure to produce commercially viable, clean gas effectively ended serious consideration of using nuclear explosives for resource extraction in the U.S. The project's data contributed to studies in seismology and nuclear containment but is largely cited as a case study in the unforeseen consequences of technological optimism. The site remains monitored by the United States Department of Energy as part of its environmental remediation responsibilities. The broader legacy is its role in shifting policy, helping to lead to the ratification of the Threshold Test Ban Treaty and cementing public skepticism toward peaceful nuclear explosions.

Category:Plowshare program Category:1973 in Colorado Category:Underground nuclear weapons testing of the United States