Kodak Ran a Secret Nuclear Device in Its Basement for Decades. It Was a Scientific Marvel.

Here’s what you’ll learn when you read this story:

• From 1975 to 2006, Eastman Kodak operated a nuclear device in a secured Rochester lab to analyze materials and create neutron images.
• It triggered fission in highly enriched uranium and allowed Kodak to test chemicals for impurities.
• Though headlines raised fears about weapons-grade uranium, Kodak’s reactor was tightly regulated; its uranium was removed under Department of Energy oversight during decommissioning.

In a secured Rochester, New York, office basement, a nuclear device the size of a fridge spent three decades quietly firing off neutrons for Eastman Kodak without a fuss. But after it was shut down and shipped away, an employee mentioned it to a reporter. Word spread, alarms rang in newsrooms, and even CNN jumped in to cover the story: Kodak had been using weapons-grade uranium in the bowels of its labyrinthine research labs.

But the truth about the reactor was stranger, and tamer, than the headlines suggested.

In 1975, Kodak powered up the country’s first californium neutron flux multiplier (CFX). Though it couldn’t live up to the sci-fi-tinged promise of its name, it leveraged a neat trick of nuclear engineering to provide Kodak R&D with an ample stream of neutrons for materials analysis.

The CFX served two purposes: neutron activation analysis and neutron radiography. The former allowed Kodak to test chemicals for impurities. By bombarding a sample with neutrons, its elements formed radioactive isotopes emitting gamma rays. Researchers could measure the energy levels of the gamma rays to identify exactly what constituted the sample.

The analysis was convenient to have on hand, but the neutron radiography was a superpower for a private company. Though it operates similarly to an X-ray, neutrons interact with nuclei and X-rays interact with electrons. That means while X-rays are powerful tools for examining heavy elements with an abundance of electrons, lighter elements and compounds, like water or film, get washed out in images. Not so with neutrons. If an X-ray shows you the crack in a pipe, neutrons will show you the leak.

The truly impressive part was how Kodak’s machine achieved its stream of neutrons. It harnessed the spontaneous fission of californium-252 (CF-252). The lab-made isotope sheds neutrons like a husky shakes off fur in July. However, this fountain of neutrons was too expensive to be the sole source (today it goes for about $30,000 per milligram). So the CFX’s designers looked to a fission standard: highly enriched uranium (HEU).

Neutrons would trickle out of the tiny CF-252 source—about 3.1 milligrams in the device’s core—and pass through 52 plates of highly enriched uranium. Behind lead shielding, the neutrons slammed into the HEU atoms to produce unstable nuclei. These often, but not always, broke apart into lighter fragments while also releasing two or three more neutrons. By the time the stream reached the sample port, the flux was up to 30 times greater than from the CF-252 alone.

This might appear alarmingly similar to a nuclear reactor at first glance: uranium fuel plates, fission neutrons, heavy shielding. The crucial difference is that the CFX was deliberately engineered to remain subcritical so that each fission produced fewer neutrons than needed to sustain a chain reaction. Without the CF-252 feeding it, the process peters out.

From 1975 to 2006, the CFX chugged along within its two-foot-thick walls and government-approved security protocols. Roughly every seven years, the CF-252 source was replenished. And aside from a license renewal snafu in 1980, the device made no waves until its existence was shared with the local newspaper—it wasn’t a secret, just unpublicized.

Unsurprisingly, when news of Kodak’s CFX went nationwide in 2012, most outlets focused on the dangers of HEU instead of its prowess for generating neutron flux. Indeed, it’s difficult to imagine trusting private corporations with the stuff atomic bombs are made of today. But the CFX was installed at a time of nuclear optimism where it was standard for top-tier universities to run reactors and ambitious companies sought to harness nuclear power.

Within its bunker, the CFX was a tightly-regulated non-threat according to Kodak and officials. The greatest danger came in the 2007 decommissioning. An old CFX is the industrial lab equivalent of an asbestos-wrapped pipe in your basement. It’s perfectly safe until you decide to remove it.

While the CF-252 component weighed about the same as a snowflake, the HEU was a more substantial 3.5 pounds. And though it takes roughly 100 pounds of it to build an atomic bomb, the fear is that bad actors would wrangle up enough small lots to create a weapon. Under the scrutiny of the Department of Energy, the plates were carefully transported to a government facility. As a testament to the security involved, no public records state who exactly moved the plates, or how they moved them beyond the safety protocols using tongs and shields made of plexiglass—which is surprisingly adept at slowing neutrons and HEU’s alpha radiation.

The real story of Kodak’s flux multiplier is less a conspiracy than a technical curiosity. It was an ingenious bit of Cold War-era engineering subject to stringent government oversight tucked under a corporate campus. The building has since been sold off by Kodak and the room long ago declared safe despite a few isotopes activated in the concrete. But it’s a reminder that the bleeding edge of technology once was radioactive.