Once Upon a Time in Idaho

Back in the day when I was bright-eyed, bushy-tailed, and intensely interested in everything nuclear, I heard a story about sabotage, or  murder, suicide, love gone wrong and a nuclear reactor that went super-critical at the Idaho National Laboratory, INL. It was a great tale. All it needed was music to become a cry-in-your-beer nuclear cowboy ballad. On a bitterly cold Idaho night in January 1961, in a remote, control-room of an experimental nuclear reactor, something went horribly wrong and three very tired young men lost their lives.

The real story is the truly remarkable way in which the Atomic Energy Commission, DOE’s predecessor, chose to handle the incident and its aftermath. The AEC was open about what had happened; clearly defining what it did and did not know. AEC representatives spoke to the American people as if they were intelligent beings capable of handling complex information. The official communication surrounding the Idaho nuclear accident stands in stark contrast to today’s environment of secrets, partial truths, and spin around issues that are not even in the same league as this incident.

In 1961, INL was known as the National Reactor Testing Station, NRTS. Located in the eastern Idaho on the high desert, the reservation encompasses about 890 square miles. Arco, Idaho Falls,

SL-1 Burial Ground monument (Photo Courtesy of AR/INEL/Gov/images)

SL-1 Burial Ground monument
(Photo Courtesy of AR/INEL/Gov/images)

and Blackfoot are the closest human enclaves. During this period, the AEC, the National Labs, and the Department of Defense were all busy coming up with ideas about how to use the impressive energy made available during a nuclear reaction.  A good use of the energy might be to provide power to remote sites like those along the DEW line was one thought. Of course in the far north-country of Alaska, Canada and Greenland where the DEW line was located, the heat generated by the reactor would be a bonus.  According to the AEC, Argonne National Laboratory designed the SL-1 reactor to do just that: 1) the components could be transported by air cargo; 2) it could operate three years with one fueling; 3) above-ground construction for Artic environments; and 4) it did not require much water.

The concept precipitated the development and construction of SL-1 in 1958. The reactor went critical, became operational, in August 1958 and, with the exception of some Boron losses and sticky rods, operated as advertised.  SL-1, Stationary Low-Power Reactor Number 1, was located about forty miles away from Idaho Falls and was one of seventeen reactors at the NRTS in 1961. Fueled with only fifteen kilograms of highly enriched Uranium-235, SL-1 was small. It had a thermal power capacity of 3 MWt.[1]  The gobbledygook means that the reactor produced three million watts of heat that could be converted to steam to drive a steam-turbine generator that produced electricity, with some losses due to inefficiencies.

SL-1 was initially operated by Argonne and was turned over to Combustion Engineering, Inc.,  the AEC operations contractor, in February 1959. Combustion Engineering successfully operated SL-1 as a test, demonstration, and training facility for both civilian and military personnel. The reactor was shut down for routine maintenance on December 23, 1960.[2]  On January 3, 1961, a four man crew initiated the re-start process. The day crew was relieved at 4:00 P.M. by a three man crew, Army Specialists John A. Byrnes (age 27) and Richard Leroy McKinley (age 22), and Navy Seabee Construction Electrician First Class (CE1) Richard C. Legg (age 26)[3].  The re-start process for the reactor is tiring and demanding but it is a routine process for which they had received extensive training. They were working on step 2, “reassemble control rods, install plugs, place block shields in place, leave top shield off”, when the incident happened.

According to the AEC report a heat detection alarm sounded at two remote fire stations and a communications station at 9:01 p.m. The alarm was continuous and a response was mounted. The temperature outside was -17 degrees Fahrenheit. By 9:17 p.m. all personnel required for entry were assembled. Personnel made several efforts to enter the facility but the radiation levels prevented any one person from staying too long. They recovered McKinley at 10:50 p.m. He died on the way to the hospital. Although he received a lethal dose of radiation, he actually died from his injuries. Byrnes, who had been lifting the center rod was found in the wreckage and Legg, who had been standing on top of the reactor vessel was impaled on the ceiling. The bodies of Byrnes and Legg, preserved by high radiation exposure, were not able to be removed for days.

So what happened? As part of the procedure, the main central control rod had to be manually pulled up a few inches so that it could be connected to its drive mechanism. For whatever reason, at 9:01 p.m. the rod was suddenly pulled too far and SL-1 went ‘prompt critical’ instantly. “In four milliseconds, the heat generated by the resulting enormous power surge caused water surrounding the core to begin to explosively vaporize. The water vapor caused a pressure wave to strike the top of the reactor vessel, causing water and steam to spray from the top of the vessel. This extreme form of water hammer propelled control rods, shield plugs, and the entire reactor vessel upwards. A later investigation concluded that the 26,000-pound (12,000 kg) vessel had jumped 9 feet 1 inch (2.77 m) and the upper control rod drive mechanisms had struck the ceiling of the reactor building prior to settling back into its original location.  The spray of water and steam knocked two operators onto the floor, killing one and severely injuring another. One of the shield plugs on top of the reactor vessel impaled the third man through his groin and exited his shoulder, pinning him to the ceiling.”[4]

According to Todd Tucker’s book, Atomic America: How a Deadly Explosion and a Feared Admiral Changed the Course of Nuclear History [5], “At 7:00 pm, Arlene had called SL-1 and told Jack that she wanted a divorce. After a year of fighting and loneliness in the Lost River Desert, Arlene Byrnes had finally had enough. Their last conversation ended with a discussion of how to split his paltry Army paycheck.” Although Byrnes must have been edgy and tired from the emotional roller coaster of a failing marriage, there is no evidence of Legg, Byrnes supervisor, being the cause of the marital problems. Legg, it seems, had his own personality issues and was not easy to work with. Although there has been much conjecture, there is also no evidence of sabotage.

SL-1 is buried where it failed, in the high desert of Idaho, and it wasn’t the ultimate nuclear cowboy song but it is still significant. The AEC was honest about its findings in the 206-page report it issued a year after the incident. The report is linked at footnote 2. The report cited both the Boron losses and the sticky control rods as matters of fact. In addition, the AEC produced a 40 minute film summarizing its report.[6]  The film is clear on the radiation exposures for the community and the recovery workers. During the accident recovery and analysis, well over 100 workers were exposed to their maximum doses of radiation. In the beginning recovery phases, workers could only stay in place for a minute or less before maximum exposure. In later phases, they could work for longer durations. After living through the Challenger and Columbia disasters, the earlier loss of the Thresher, September 11, 2001, Benghazi, FDA, and IRS issues, it is difficult to imagine that level of honesty. The AEC has been challenged on the conclusion of cause in its findings but not on the data. It is time to return to a culture where accountability from the government is expected and, to the extent it is able, the truth is stated.


[1] Database of radiological incidents and related events–Johnston’s Archive; Wm. Robert Johnston; 17 October 2007; SL-1 reactor excursion, 1961; http://www.johnstonsarchive.net/nuclear/radevents/1961USA1.html

[2] IDO Report on Nuclear Incident at the SL-1 Reactor January 3, 1961 at the National Reactor Testing Station; January, 1962; IDO19302; http://www.id.energy.gov/foia/PDF/IDO-19302.pdf

[3] “Nuclear Experts Probe Fatal Reactor Explosion”; Times Daily; January 5, 1961;  http://news.google.com/newspapers?id=YAAsAAAAIBAJ&sjid=1MYEAAAAIBAJ&pg=4392,459966&dq=idaho+nuclear+accident&hl=en

[5] Tucker, Todd (2009); Atomic America: How a Deadly Explosion and a Feared Admiral Changed the Course of Nuclear History; New York: Free Press; ISBN 978-1-4165-4433-3  http://www.amazon.com/Atomic-America-Explosion-Admiral-Changed/dp/0803234023/ref=sr_1_1?s=books&ie=UTF8&qid=1370480060&sr=1-1&keywords=atomic+america

[6] 1961 Nuclear Reactor Meltdown : The SL-1 Accident – United States Army; http://www.youtube.com/watch?v=FAKcWM-yBkI


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