The reactor building and its contents were buried in a trench 1,600 feet away from the original SL-1 building site. The cleanup took 13 months and $2.5 million. Much was learned about managing power reactor disasters, and the question of what had happened was answered in great detail, down to the millisecond.
What was never answered by detailed forensic analysis was: Why did Byrnes pull that control out? He knew good and well what it would do if it came up to four inches. Why jerk it out all the way? There are, to this day, a few conflicting opinions, ranging from it was a murder-suicide to he was exercising the rod to clear the bent boron. In my opinion, Byrnes was showing off for McKinley, the new guy from the almighty Air Force. The Air Force was running the dangerous, super high-tech HTRE experiments down the road at Test Area North, and the Army was stuck with this cheap, low-power rig that was just sitting here making a slight turbine-hum. Byrnes wanted to give McKinley a thrilling blip on the cutie-pie radiation detector he was holding by bouncing the main rod. He knew that if he could bring it up to supercritical for just a split second, the power would drop again quickly as the control went back down. No harm done, but he bet himself that he could make Air Force lose control of his bladder. The thing was heavier than it looked. He wiped his sweaty palms on his pants, braced, and put both arms into it. Up she came. They never knew what hit them. Their nervous systems were destroyed before the senses had time to register the violent event.
It was a tragic loss of life, and the general attitude toward small, simple, cheap nuclear power was affected. The Army went on to deploy the PM-2A portable medium-power reactor in Greenland, the PM-3A at McMurdo Station in Antarctica, the MH-1A mobile high-power reactor at the Panama Canal, the SM-1A stationary medium-power reactor at Ft. Greely, Alaska, and the PM-1 at Sundance, Wyoming. They even developed the ML-1 at the NRTS, the first nuclear power plant that would fit on the back of a truck. It all ground to a stop in 1977 when the need for remote power and the money to support it both drifted away. It was not at all a bad idea, but commercial nuclear power production moved off in the opposite direction, toward bigger, more complicated, more expensive installations, and the SL-1 incident was a reminder of the dangers of making it too simple. The accident had proven that there was no such thing as foolproof.
The snowcap over Greenland into which Project Iceworm was dug turned out to be one big, slow-moving glacier. The rooms and tunnels so carefully carved out of the ice deformed and shrank with time. Every month, 120 tons of ice had to be shaved off the inside walls, and by the summer of 1962 the ceiling in the reactor room had come down five feet. In July 1963 it was clear that this bold step in missile positioning was not going to work, and the PM-2A reactor was shut down and shipped back home. By 1966, Camp Century was unlivable, and it was given back to nature. When last visited in 1969, it was completely wrecked and buried under a great deal of new snow.
The deep snow cores taken at Camp Century are still in use today. These long cylinders of snow cut from the glacier are a record of the climate and atmospheric conditions for the last 100,000 years, and they have been used to map the carbon dioxide history on Earth since the emergence of mankind.
The last steam explosion in Idaho was the final in a series of experiments with the SPERT-I, or the Special Power Excursion Reactor Test One, on November 5, 1962. One would think that enough was learned in the BORAX–I and the SL-1 blow-ups to pretty much give us what there was to know about water boiling too fast in a reactor tank, but this odd experiment was funded by the AEC. It, like BORAX, gave a bit more of a show than was anticipated, and it went down in history as another accidental power excursion at the NRTS. The incident was all recorded as a movie in slow-motion at 650 frames per second.[109]
The reason for the SPERT experiments had to do with the expanding need for nuclear specialists in the 1950s. The AEC was aware of a projected shortage of nuclear engineering and health physics graduates in American universities, and technical campuses needed small research reactors in place to encourage these studies and excite some interest in nuclear topics. The Aerojet General Corporation had already introduced an inexpensive “swimming pool” reactor for use in schools. It was simply a concrete-lined pool of water, sunk in the floor, with uranium fuel assemblies and control rods clustered in the middle. “Is it safe?” asked the AEC. “What would happen if a control rod came loose and dropped out the center of the core?”
It would explode, of course, with the water shooting out the open top of the reactor and hitting the roof really hard, but that was not a sufficient answer. Details of everything that could possibly happen to an open-topped, water-moderated, low-power reactor were demanded. The SPERT contract was given to the Phillips Petroleum Company, and a site was chosen about 15 miles west of the eastern boundary of the NRTS. The first of four SPERT reactors was started up in June 1955, and it was run through a series of torturous accident scenarios.
The setup was very much similar to BORAX–I, but it was enhanced with a metal shed covering the reactor. Controls were inserted through the bottom of the reactor core leaving the top completely open, with one master control in the center. Two periscopes looked down into the core from above, and a tilted mirror showed the open reactor top from the side. These optical features were used to make motion pictures of every experiment simulating wrongful operation by undergraduates horsing around with the controls.[110] Nuclear instruments and recording procedures had improved since BORAX, and better data collection was anticipated. Experiments with fast power transients blew the water out the top of the reactor, just as seen in the BORAX excursions. The fuel was the same as was used in most of the test reactors at NRTS, thin plates of aluminum-uranium alloy clad with pure aluminum. It was not meant as a high-temperature fuel, and some plate warpage and slight melting were observed in the core.
November was the end of the open experiment season in Idaho, as the temperature began to drop to Greenland levels, and the team was out of tortures for the SPERT-I. SPERT-II was designed and ready to build. As one last experiment for 1962, the team wanted to simulate AEC’s worst fear, that the main control rod would fall out. The control-rod drive was modified to break free and fall with gravity, and the metal roof was removed so that the driven water would have nothing to blow away. A 3.2-millisecond period was predicted, with some fuel melting this time. The test was not cut out to be such an event as the BORAX–I excursion. SL-1 had taken the thrill out of seeing water reactors explode.
It was a sunny day in the desert, and the wind was calm. Three … two … one … RELEASE. The main control rod went into freefall. The little reactor suddenly lit up with a blue flash in the mirror as 30.7 megajoules of energy came alive and started heating the fuel. All 270 fuel plates melted, and the fission process shut down completely, as predicted. Everything was going according to plan for about 15 milliseconds, and then all hell broke loose as the unexpected transpired.
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On May 3, 1958, Frederic de Hoffman announced the introduction of the Test, Research, and Isotope reactor of General Atomic, or the TRIGA. It was a brilliant design, started as an exercise for young nuclear engineers by Dr. Edward Teller, co-inventor of the H-bomb and the inspiration for the movie “Dr. Strangelove, Or How I Learned to Stop Worrying and Love the Bomb.” Dr. Freeman Dyson, also a nuclear genius, contributed to the concept, and the design was influenced by findings at the NRTS in the BORAX and SPERT programs. The TRIGA pool reactor was “safe even in the hands of a young graduate student,” which is saying a lot. The unique fuel formula was a mixture of uranium and zirconium hydride. Being co-located with the uranium, the hydrogen moderator would heat instantly in the event of a fission runaway, and the hot hydrogen would lose its ability to moderate the neutrons down to the advantageous low speed. The result was a reactor that absolutely could not be made to explode or melt down. The TRIGA is still available from General Atomics of San Diego, California. Three new ones were sold recently overseas.