The Site A/Plot M Disposal Site is located within

Red Gate Woods Red Gate Woods is a forest preserve section within the Palos Forest Preserve, a division of the Forest Preserve District of Cook County, Illinois. It is located near where the Cal-Sag Channel meets the Chicago Sanitary and Ship Canal. In the wo ...

and situated on the former grounds of

Argonne National Laboratory Argonne National Laboratory is a science and engineering research United States Department of Energy National Labs, national laboratory operated by University of Chicago, UChicago Argonne LLC for the United States Department of Energy. The facil ...

and its predecessor, the University of Chicago

Metallurgical Laboratory The Metallurgical Laboratory (or Met Lab) was a scientific laboratory at the University of Chicago that was established in February 1942 to study and use the newly discovered chemical element plutonium. It researched plutonium's chemistry and m ...

in Cook County, Illinois and is part of the

Palos Forest Preserve The Palos Forest Preserve, a division of the Forest Preserve District of Cook County, is a 15,000 acre nature reserve in Palos Township, Illinois. The division headquarters are in Willow Springs. The preserve features the Palos Trail System. ...

. The site contains buried radioactive waste from contaminated building debris, and the

Chicago Pile-1 Chicago Pile-1 (CP-1) was the world's first artificial nuclear reactor. On 2 December 1942, the first human-made self-sustaining nuclear chain reaction was initiated in CP-1, during an experiment led by Enrico Fermi. The secret development of t ...

(CP-1/CP-2), and

Chicago Pile-3 Chicago Pile-3 (CP-3) was the world's first heavy water reactor. One of the first research reactors, it was built in 1943 near Palos Hills, Illinois, original site of Argonne National Laboratory. Joining CP-1/CP-2, it first went critical on 15 ...

(CP-3) nuclear reactors. "Site A" was an early Manhattan Project code for the facility. "Plot M" was the code name used for the disposal ground.

Site history

During a horseback ride in early 1942, the head of the Metallurgical Project, Professor

Arthur Compton Arthur Holly Compton (September 10, 1892 – March 15, 1962) was an American physicist who won the Nobel Prize in Physics in 1927 for his 1923 discovery of the Compton effect, which demonstrated the particle nature of electromagnetic radia ...

, identified a plot of land in what was then known as the Argonne Forest, as the location for part of the Manhattan Project. Shortly after the December 1942 demonstration of the first self-sustaining chain reaction at the University of Chicago, the research group led by

Enrico Fermi Enrico Fermi (; 29 September 1901 – 28 November 1954) was an Italian (later naturalized American) physicist and the creator of the world's first nuclear reactor, the Chicago Pile-1. He has been called the "architect of the nuclear age" and ...

needed to move to the larger, more remote laboratory campus. The U.S. Army Corps of Engineers had leased from the Forest Preserve District of Cook County, and placed the wartime reactor laboratory on within the forest. The first reactor, CP-1, was disassembled and moved to Site A in March 1943, renamed as Chicago Pile 2. In May 1944 the laboratory first operated a second, heavy water-moderated reactor, CP-3 on the site.

obtained an even larger, permanent site in Du Page County in 1947 and began moving its operations out of Site A to the new site. The two reactors operated until 1954, conducting reactor research and production of tritium. Decontamination and demolition of the buildings began in 1955. The reactors were defueled and the concrete shell for CP-3 was imploded and buried. In 1956 the property was returned to the forest preserve. Two granite monuments mark Site A and Plot M. Marker at Site A

Plot M Nuclear Burial Marker, Palos Forest Preserve, Illinois

The Site A marker reads:

THE WORLD'S FIRST NUCLEAR REACTOR WAS REBUILT AT THIS SITE IN 1943 AFTER INITIAL OPERATION AT THE UNIVERSITY OF CHICAGO THIS REACTOR (CP-2) AND THE FIRST HEAVY WATER MODERATED REACTOR (CP-3) WERE MAJOR FACILITIES AROUND WHICH DEVELOPED THE ARGONNE NATIONAL LABORATORY THIS SITE WAS RELEASED BY THE LABORATORY IN 1956 AND THE U.S. ATOMIC ENERGY COMMISSION THEN BURIED THE REACTORS HERE.

The Plot M marker reads:

CAUTION—DO NOT DIG Buried in this area is radioactive material from nuclear research conducted here 1943–1949. Burial area is marked by six corner markers 100ft from this center point. There is no danger to visitors. U.S. Department of Energy 1978

The markers have since been vandalized, with vandals chiseling off the word "NO" from the sentence "There is no danger to visitors". Plot M was a dump for low-level radioactive waste generated at the site between 1943 and 1949. Initially buried in trenches, later in steel bins, the waste included tritium, uranium, and fission products in various forms including contaminated equipment, animal carcases, and solids. In 1949 the burial of waste at the site was halted, and the dump was covered with grass until 1956, when a concrete cover was installed to protect the landfill from rainwater. Surveillance of the site since the demolition in the 1950s has found small amounts of soil contamination with uranium and fission products, and some wells in Red Gate Woods had tritium concentrations as high as in the late 1970s. In April 1998 the fence separating Site A from the rest of Red Gate Woods was taken down after a DOE determination that the risk to the public while enjoying the forest preserve is minimal.

Location

Site A is located near . Plot M is located near . During the Glenwood stage of Lake Chicago, this was part of Mount Forest Island, a triangular island long and wide, rising above the surrounding waters.
Epoch of glacial retreat:Chicago
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References

External links

Forest Preserves of Cook County Red Gate Woods: ‘Site A’
{{DEFAULTSORT:Site A Plot M Disposal Site Radioactive waste repositories in the United States Manhattan Project sites Argonne National Laboratory Geography of Cook County, Illinois

Site history

Location

See also

References

External links