The BORAX Experiments were a series of five destructive tests of boiling water reactors built and conducted by Argonne National Laboratory in the 1950s and 1960s at the National Reactor Testing Station in eastern Idaho.
The synopsis of the final test of BORAX-I in 1954, as seen in the photos above, is as follows: “The (test was) carried out by withdrawing four of the five control rods far enough to make the reactor critical at a very low power level. The fifth rod was then fired from the core by means of a spring. In this test, the rod was ejected in approximately 0.2 seconds. After the control rod was ejected, an explosion took place in the reactor which carried away the control mechanism and blew out the core. At half a mile, the radiation level rose to 25 mr/hr. Personnel were evacuated for about 30 minutes.”
The destruction of BORAX-I caused the “aerial distribution of contaminants resulting from the final experiment of the BORAX-I reactor” and the likely contamination of the topmost 1 foot of soil over about 2 acres in the vicinity. The site was cleaned prior to being used for subsequent experiments. The BORAX-I burial ground is located roughly 820 m (2,730 ft) northwest of the Experimental Breeder Reactor-I, a publicly accessible national monument.
The only demonstration of BORAX-I principles during a real nuclear accident occurred several years later within the SL-1 (Stationary Low-Power Reactor Number One) nuclear reactor operated by the United States Army, in which the reactor underwent a steam explosion and meltdown, subsequently killing its three operators.