In 1974, Kodak purchased a small nuclear reactor and installed it in an underground bunker in the Kodak Park industrial complex in Rochester, New York. The neutron flux multiplier was used for experiments in neutron photography, which lasted until 2007.
Californium-252 was the source of neutrons, plates with uranium were used as flow multipliers, and highly enriched uranium was accumulated as waste in the laboratory. According to experts, for the American industrial sector it was a unique device. There are no more than 50 such accelerators with California in the world, almost all of them are located in Russia, and not a single American company has had one, only Kodak.
Neither the city of Rochester, nor the state of New York, and even almost none of the Kodak employees, except for a few engineers and company management, knew about the existence of an underground bunker 7x4 m under the building 82. Information has now been leaked to public access thanks to the
revelations of a former Kodak employee who has worked with the reactor for almost twenty years. Information confirmed in the US Nuclear Regulatory Commission.
California / Californium neutron flux multiplier (CFX) neutron multiplier. Photo from the archives of the US Nuclear Regulatory Commission')
A former Kodak research scientist Albert Filo said that uranium was alloyed with aluminum and sealed in the form of plates in sleeves that have been in the laboratory for 30 years.
In 2007, 1.59 kg of uranium produced by the reactor was sent for processing to California. Enriched to 93.4%, uranium is quite suitable for creating nuclear weapons, although 1.59 kg is obviously not enough, at least 40 kg is needed.
List of private nuclear reactors in the US (xls)

In Russia there is information about
109 scientific nuclear reactors .