Uranium fever hit Utah as the Cold War was raging. Between 1950 and 1956, over 50,000 uranium claims were filed by prospectors for mines in the San Rafael Swell — a giant dome-shaped geologic feature made of sandstone, shale, and limestone that was pushed up during the Paleocene era as a result of subduction and deformation.

About 15 miles west of Green River, Utah, I-70 cuts through the San Rafael Reef, which is the eastern edge of the Swell. The San Rafael Reef View Area (westbound) and the Spotted Wolf View Area (eastbound) provide magnificent views of the feature.

Uranium fever was everywhere in the 1950s, as prospectors flocked to the Southwest to seek their fortunes. Green River was the staging area for mining, along with processing facilities. Moab became a bustling tourist destination, not only for its natural beauty, but also because Charlie “The King of Uranium” Steen, with the success of his Mi Vida uranium deposit, brought development.

The Atomic Energy Commission surveyed the area in modified Piper PA-18 Super Cubs as part of its uranium exploration program in the 1950s. The AEC’s fleet of 10 low, slow, and inexpensive Super Cubs had scintillation counters in the rear of the plane to detect gamma radiation.

Across the parking lot from the EBR-1 outside Arco, Idaho, you’ll find the decommissioned HTRE-2 and HTRE-3 in large test assemblies. These Heat Transfer Reactor Experiments were tests of nuclear propulsion in aircraft. General Electric J47 turbojet engines were modified (renamed X-39) to use heated compressed air from a heat exchanger as part of the nuclear reactor rather than from combusting jet fuel. The X-39 engines would have been used in the proposed Convair X-6.

The reactor and heat transfer system was tested on a Convair NB-36 (converted B-36 Peacemaker) with 47 recorded flights between 1955 and 1957. The reactor was turned on through many of these flights not to power the aircraft but to test and collect data on the feasibility of a sustained nuclear reaction on a moving platform.

The HTRE-2 used vertical control rods with a removable core. The HTRE-3 was built to test horizontal control rods to accommodate the orientation in an airframe. The test assemblies were going to be decontaminated and decommissioned for burial in the Radioactive Waste Management Complex. However, preservation was chosen instead, and the assemblies went on display on May 22, 1989. This includes the lead-shielded locomotive used for the test assemblies and that would have towed the proposed planes inside the hangar.

The program was canceled on March 28, 1961, by President Kennedy, due to public safety concerns, advances in ballistic missiles, and aircraft design innovations, after spending more than a billion dollars developing the concept.