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An Idea is Created
United States Army decides a need for a nuclear reactor plant for radar stations in the Arctic region, during the Cold War. -
SL-1 Fully Operational
Stationary Low-Power Reactor Number 1 (SL-1), a U.S. Army experimental nuclear reactor, is built and fully operational. Created as a research project to develop a small reactor that could provide enough electricity and heat for radar stations in the Arctic region, to monitor for soviet missiles, while being cost effective for the U.S. Army. (SL-1 puts out 200 kW of electricity and 400 kW of heat). -
Red Flags
SL-1 was having issues with its control rods, which absorb neutrons to regulate fission reactions. From 02/1959 - 11/18/1960, there were 40 cases of stuck control rods occurring at a 2.5% failure rate. From 11/1960 - 12/1960, the last month before the explosion, an increase of 23 cases of stuck rods occurred with a failure rate of 13%. As stated by the SL-1 Project Manager, W. B. Allred, these issues were never brought up to him by Paul Duckworth, the SL-1 Operations Supervisor. -
9:17pm
A health physicist arrives on scene and approaches the stairwell leading into the building with a radiation detector reading of 25 R/hr. The physicist then proceeds to grab a high-scale ion chamber detector, a Jordan Radector AG-500 meter, which reads 500 R/hr on the way into the building. A fireman and the health physicist don PPE (SCBAs) and enter the building. -
10:30pm
Army Specialist Richard Leroy McKinley, 27, is found on the floor moaning with sustained head injuries. Army Specialist John A. Byrnes, 22, is found on floor pulseless and is pronounced dead at the scene. During McKinley's rescue extraction, one fireman's breathing apparatus fails and continues to extract McKinley for 3 full minutes, while breathing in contaminated air. At 10:38pm Navy Seabee Richard C. Legg, 26, is found dead impaled to the celling via a reactor plug. -
The Reactor Explosion
Due to a control rod being withdrawn too far out of the reactor (2 ft), the core power of the reactor reaches 20 GW within 4 milliseconds. A power density of 6,000 times its operating limit, releasing 80 curries of iodine-131 and 1,100 curries of fission products into the atmosphere. This incident marks the only U.S. reactor incident to cause instant deaths. -
9:10pm
After the steam explosion, the facility's heat sensors are trigged. Six fireman from the local fire station respond to the scene. Noting nothing abnormal, they proceeded to enter the building with hand held radiation detectors that indicated a reading above the max range (200 R/hr). The fireman then retreated out of the building. -
Legg's Body Retrieval
Relays of two rescuers out of 10 took 65 second intervals of radiation exposure, using sharp hooks on ends of poles to release Legg's body from the celling. In an attempt to avoid Legg's body falling into the reactor directly bellow him, a makeshift stretcher was constructed and fixed to crane to retrieve his body when it was released from the ceiling. -
Reactor Removal & Dismantle
General Electric is hired to dismantle and remove reactor remains. 475 volunteers from the U.S. Army and the Atomic Energy Commission participate in the site clean up. Hot spots of upwards of 400 R/hr are recorded during the cleanup. -
Site Clean Up Completion
A burial ground is constructed 1,600 ft from the original site of the reactor. Radioactive waste is buried to minimize radiation exposure to the public and site workers. Burial depth ranges from 8-14 ft deep. Site clean up took around 24 months. -
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Gamma Radiation Surveying
The Radiological & Environmental Sciences Laboratory conduct gamma radiation surveys. -
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Particle Picking
Particle picking occurs at the site. Results from survey indicate that cesium-137 is the primary surface soil contaminant. -
"Hot Spot"
A hot spot of higher radioactivity is found around and within SL-1's burial ground with radioactivity measuring 0.1 - 50 mR/hr. Background radiation is measured at 0.2 mR/hr. The planning for a need for a "cap" is determined based of these findings. -
Capping
Physical capping is placed over SL-1's burial mounds with an engineered barrier made of native materials is built and placed to contain radiation within the burial grounds to plants and animals.