A tour of Chicago's nuclear fringe definitely wouldn't be complete without a stop at the Palos Forest Preserves located just outside the city to the southwest. Inside and accessible only via hiking trails are the 19-acre area known as Site A and the 150x140-foot area known as Plot M, respectively the site of the world's first nuclear reactors and radioactive waste dumping ground.
Of course, the first nuclear reactor (Chicago Pile-1, or CP-1) was located on the campus of the University of Chicago. But just a few months after its first nuclear chain reaction in December 1942, CP-1 was dismantled and reconstructed on Site A. It was then renamed CP-2.
A second reactor, known as Chicago Pile-3 (CP-3), was also built. In 1950, this reactor was renamed CP-3' (CP-3 prime) when it was rebuilt with a new design. Also built on Site A were about 35 buildings housing laboratories, dormitories, a cafeteria, dog kennels and a lead foundry.
According to the Department of Energy, all research programs at these facilities ended in 1954 and moved 3 miles to the east to a new complex, the Argonne National Laboratory. While the fuel for both reactors and heavy water were taken somewhere else, all buildings on Site A were torn down and, along with most of the equipment, buried where they stood.
An excavation approximately 100 feet across and 40 feet deep was prepared between the two reactors. The reactors themselves were approximately 180 feet apart. The 800-ton, concrete-filled, shell of the CP-3 reactor was buried by excavating around it on three sides and detonating strategically placed explosives in the earthen “pedestal” supporting it. The reactor shell rolled and ended upside down in the excavation. The concrete shield of CP-2 was demolished and pushed into the same excavation. The buildings that housed the reactors were demolished and placed in the excavation. The excavation was then backfilled, leveled, and landscaped. The top of the CP-3 reactor shield is approximately 23 feet below ground surface; rubble and building debris fill the excavation both laterally and vertically to within a few feet of the surface.
Placed at the approximate location of the burial site is a large engraved (head)stone describing the historical significance of Site A.
Located 1,500 feet north of Site A is Plot M. There, radioactive waste and radioactively contaminated laboratory articles generated from research activities at Site A were buried.
The method of disposal sounds rather crude in comparison to today's vast subterranean nuclear sarcophagi but nevertheless underscores the ongoing uncertainties over the safety of more modern burial strategies — or any of them, in fact.
Apparently both solid and liquid waste was buried from 1944 through 1946. Liquid wastes were disposed in intact containers, which may have subsequently been breached. Through 1948, waste was buried in 6-foot deep trenches and covered with soil to minimize radiation release; beginning in May 1948 burial took place in steel bins. The steel bins were removed in 1949 in a search for some missing uranium-235, which was subsequently found. Instead of reburying the bins, they were shipped off site for disposal; the waste buried in trenches was allowed to remain in place. Records of items placed in Plot M are incomplete, but known items include animal carcasses, building debris, clothing, contaminated equipment, air filters, paper, and other radioactive and hazardous materials.
Dumping at Plot M stopped in 1949, and for a few years was covered with soil and grass, which weren't much protection against water infiltration and seepage. Then in 1956:
[A]n inverted concrete box was constructed over the entire burial plot. The concrete walls of the box are 18 inches thick and extend 8 feet into the ground. A 1-foot-thick concrete slab was poured over the entire disposal area. The purpose of the concrete barrier is to prevent excavation of the site and to impede the flow of water through the buried radioactive materials. The concrete slab was covered with about 2 feet of soil [and] grass was planted.
Interestingly, the DOE does not mention how and where contaminated material were buried during the years when Plot M had already been decommissioned but Site A was still in operation.
Just as at Site A, there's a small stone monument briefly describing past top secret activities. Situated as it is atop a gently sloping mound entombing radioactive waste (a malformed Mt. Parnasus, if you will) and surrounded by pastoral landscaping, one half expects finding an additional inscription, which reads: Et in Arcadia ego.
It's interesting to see that where the marker assures visitors that the area poses no danger to them, the word “NO” has been chiseled out by vandals. Perhaps it's a hint that all warning signs are bound to fail, not just the signal they carry but the physical sign itself. No matter how many far-forward scenarios have been taken into count and design for in countless ideas competitions (not to mention those ideas competitions for ideas competitions), potentially dangerous landscapes, even lethal ones, will always be attractive destinations.
The tourists will come in their CLUI buses regardless of the danger. And the “atomic priesthood” will have its schisms and periods of iconoclasm, when delirious, chisel-happy monks will rebel against the text and rampage through their irradiated basilicas.
But in the meantime, you can have a picnic near Plot M.