Samsung fined just $8K for exposing chip fab workers to X-ray radiation Two Samsung employees suffered X-ray radiation exposure at a chip fab near Seoul, and electronics giant is only facing a small ₩10.5 million (less than $8,000) fine for two violations of South Korea's Atomic Energy Safety Act. The country's Nuclear Safety and Security Commission (NSSC) announced its findings into an …
The translation could be making it a little murky but it could be entrance skin dose, which is basically all the radiation the individual was exposed to, rather than the radiation that was absorbed. This is handy to know because the absorbed dose calculations might not take back scatter into account when calculating the absorbed dose. However, it's still a surprisingly large difference.
> technicians who had worked on the machine said they'd never changed the interlock wiring
Yeah, I'm sure this is one of those shit design interlocks that actually prevents you from using the machine, so the interlock lasts about as long as it takes someone to find a screwdriver.
Most of these, if they spent maybe another hour on design and 10 cents more on materials, they would have something that would actually protect people.
But no.
There was an incident like this in the 1980's at Park Station in Johannesburg. IIRC somebody there bought a microwave oven for warming meat pies at the kiosk he operated there. He stuck something into the interlock switch so that he could keep the door of the oven open while he operated it (or removed the door). Guy landed up having a well cooked hand eventually, and this is when the story came out. The problem with having other people around you is that they sometimes do stupid things that may end up affecting you in a very bad way: building a nuclear reactor in the shed, storing high explosives in a garage that caught fire, that time in the USSR when the scientist stuck his head into an operating atom accelerator because the broken warning light bulb hadn't been replaced. I'm wondering if the faulty wiring here wasn't done maliciously if it's not in the maintenance logs.
"Guy landed up having a well cooked hand eventually"
There are much worse things that can happen. Hands have a good blood supply to carry away heat
EYES do more or less exactly the same thing as egg whites do (vitreous, lens and cornea) and have no heatsinking to speak of
This is why you never look down the end of an uncapped waveguide
When I was a kid I saw many examples of what I came to think of as the standard "technician-bypassable interlock switch". The access panel, when closed, depressed a nylon post, which closed a normally-open switch. A technician would open the panel, pinch the nylon post, and pull it out to a detent-stop, which would close the switch, bypass the "protect" mode, and allow power to flow. Closing the panel, or pressing the nylon post returned the switch to "protect" mode.
Are these things no longer used?
They are, and I think they are normally designed so that the interlock comes back into play when the device is reassembled, as you say. If not, it's a bad design that requires the engineer to remember to reset it, but I'd have thought that would have been mentioned. Another design issue is when the device is hard to use with the interlock in place, so users disable it, maybe under "productivity pressure" despite any formal instruction not to, and then of course everyone is very vague about how it could have happened... It's not clear if the users were exposed over some time or in a single incident, or if the interlock was checked as part of routine maintenance (maybe in the original report, I dunno). Equally possible that the interlock was never working properly, but new users/procedures caused the exposure to happen when it didn't before.
> Another design issue is when the device is hard to use with the interlock in place, so users disable it, maybe under "productivity pressure"
I know of a site which had two activation buttons on one piece of equipment spaced so that you had to use both arms to push the buttons
It was built that way for a reason - as the guy who fragged one of the switches so he could use it one-handed found out. It ripped his arm clean off at the shoulder
That made for an "Interesting" H&S audit and a fairly icky cleanup job in equipment that made cardboard boxes
"they are normally designed so that the interlock comes back into play when the device is reassembled"
That assumes the designers know such things exist.
I've worked on high voltage RF equipment from the same maker where the older kit had such things and the newer stuff had to be bypassed for service using various unsafe methods that then had to be removed to keep things safe under normal conditions
Putting those doses in context, "one chest xray" is about the same as an hour's flight at 30,000 feet and we don't see aircrew all keeling over like flies
It's not just the dose that makes the poison, but also the duration of the delivery
These workers would be fine. We are utterly paranoid about radiation exposure (admittedly with good reason) but it really does take a high dose to cause serious issues - There's an XKCD for that
The fine is because the safeties were bypassed and should be higher because otherwise as soon as the inspectors are gone the workers will bypass them again
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