Reactors Designed by Argonne National Laboratory
Heavy Water and Graphite Reactors
Argonne designed, built, and operated reactors using a wide variety of types of fuel, neutron
moderator, and coolant materials to explore the technological possibilities of nuclear energy.
The resulting experimental data and analyses formed a large portion of the design basis for many
reactors that were built to produce plutonium, tritium, and medical isotopes, as well as for the
25% of commercial reactors in the world that are not light water reactors.
CP-5 (Chicago Pile 5 Reactor)
The Argonne's Chicago Pile 5 (CP-5) reactor was a research workhorse, providing neutrons for experiments on the structure and behavior of materials. It started operation in 1954 and was used until 1979. Technicians for Illinois’ first commercial power plants were trained at CP-5.
CP-5 was used for a good deal of materials research starting in the 1970s, its major mission was to study the physics of atomic nuclei. During its 25-year career, CP-5 attracted hundreds of scientists from industry, universities and government laboratories all over the world. It opened new horizons in nuclear physics and materials research. It taught future scientists, trained reactor operators, and served as a model for many other research reactors in the United States and abroad. CP-5 was the fifth and last member of the distinguished family of "Chicago Pile" reactors, whose legacy ranges from the earliest efforts to develop nuclear reactors to current environmental research aimed at learning how to retire them safely.
When Chicago Pile 5 retired from active service as a materials research reactor in 1979, it marked the end of operations for the Chicago Pile reactors. The decontamination and decommissioning (D&D) of the CP-5 Research Reactor Facility was initiated in 1991 and completed in 2000.
For more information on CP-5:
Decommissioning of CP-5
CP-5 Flickr Gallery (by Argonne National Laboratory) or
“Chicago Pile” Flickr Gallery (by Argonne National Laboratory) for available photos of all the "Chicago Pile" reactors
In 1953, ZPR-2 experiments at Argonne demonstrated the design feasibility of the Savannah River
Production reactor in South Carolina, constructed in 1954.
Hanford Basic Design
Fuel-processing studies for the production reactors at Hanford were carried out in Argonne
Buildings 205 and 310 in the early 1950s.
ZPR-7: Thorium-Uranium D2O Reactor (THUD)
The ZPR-7 reactor was used to supply physics design information required in connection with
several phases of Argonne's boiling reactor program. The physics of Uranium-thorium fuels were
explored. The facility helped to perform critical and mockup experiments, necessary to achieve
higher precision for the determination of reactor power distribution patterns, effect of non-uniform
void distributions, kinetic behavior, control rod effectivness, importance of streaming and
localized substitution effects.
CP-6 (Chicago Pile 6 Reactor)
CP-6 was designed at Argonne, and was an enlarged, improved version of Chicago Pile 3 (CP-3). Five of the reactors based on the CP-6 design were built at the
Savannah River Plant for production of materials for military use. Intended as a backup design
for the Hanford Production Reactors, these operated for decades.
Last Modified: Wed, September 25, 2013 5:41 PM