What exactly is an “industrial nuclear device”? And what industry uses them? Something isn’t right in this story... I think.
One common use is making radio isotopes for medical use. They use commerical linear accelerators.
Cross field amplifiers, at type of radio frequency amplifier uses atomic isotopes.
The chemical industry uses nuclear devices as level transmitters.The LT gives a reading to the control room operator to monitor levels in tanks, vessels, etc..They are pretty common.
Super accurate atomic clocks is one application for Caesium.
There have been accidents in the past, and lost sources. In Mexico, a hospital received a cobalt radiotherapy machine as a donation. They had no one to use it, so junked it. It was melted into a batch of cast iron and cast into ornate table legs for outdoor restaurant tables. Just by chance, a tractor trailer was carrying some of these in a shipment, and had to make a delivery to Eberline, and it triggered all the detectors.
In South America, a janitor found a Cesium well logging source on the floor, and put it in his back pocket, and was wandering around asking people what it was. Here is one person who did not have to go the Vegas to lose his @ss.
There have been others.
The oil and gas industry uses a lot of VERY radioactive isotopes for well-logging purposes.
Its the typical off the shelf 100 megaton thermonuclear device that the oil industry routinely uses to seal off rogue oil leaks.
Well loggers to help characterize rock strata use Cs-137. Every couple years one wanders off in NM and has to be found. Not that you could make any kind of truly dangerous device with it.