A Kodak industrial facility in Rochester, N.Y., was home to a little-known nuclear reactor containing weapons-grade uranium, the Democrat and Chronicle newspaper reported.

The research reactor -- which was the size of a refrigerator -- was housed in a bunker underneath one of the buildings at the former Kodak Park site, the newspaper reported.

Kodak used it to check chemicals and other materials for impurities, as well as testing imaging techniques.

Although the reactor was not a secret, it was unclear if Kodak informed police and fire departments of its existence. Local authorities were also unaware of its existence.

The reactor contained more than 3lbs (1.36kg) of highly enriched uranium -- the same material used to construct nuclear weapons. The uranium was removed in November 2007 in protective containers, the report said.

Company spokesman Christopher Veronda said he could find no record that Kodak ever publicly announced the reactor.

Albert Filo, a former Kodak research scientist who worked with the device for nearly 20 years, told the newspaper, "It was a known entity, but it was not well-publicized."

Information on nuclear power plants has been restricted since the 2001 terrorist attacks.

Kodak employed the device to carry out research into neutrons -- subatomic particles that can create an image of a material without damaging it.

In 1974, it acquired a neutron flux multiplier -- which multiplies the neutrons flowing from the core of the reactor.

Access to the chamber was restricted, and no one was allowed into the room while the reactor was in operation.

Veronda said, "This device presented no radiation risk to the public or employees. Radiation from the operation was not detectable outside of the facility."