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Comment by pavel_lishin | Hacker News Reader

some embedded controllers in racks in the auxilliary deisel generator control rooms have EPROMs which have been known to be erased by camera flashes in the past

Am I the only one terrified of the fact that any part of a nuclear reactor can be tampered with by a flash of light?

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It's a known problem, but not a cause for concern:

http://www.hanford.gov/rl/?page=671&parent=666

The worst that will happen is that an emergency/safety system will be tripped accidentally. The workaround is to mask the EPROM windows (with tape, I assume) after programming them.

EPROMS usually have a paper sticker glued onto them. As the sticker had details printed on them. The glue on most printer-compatable stickers gets old with age and thus they fall off.

Due to pricing quirks, the EPROMs with windows were far cheaper than the same chips that didn't have quartz windows on them. They weren't ROMS, they were the same IC, but with an opaque lid.

Funny, I remember windowed ceramic parts as being quite a bit more expensive than epoxy plastic with no window, which would be a OTP (one time programmable) EPROM. Use the high dollar windowed devices during development or for unstable projects, then switch to plastic OTP once the code settles down for better production margins.

The good stickers we used were metallized polyster, I think. They were a bit more opaque than paper, as measured by the time it took to UV erase a device.

I'm sure things have changed, but the last time I made stuff with EPROMs was back in the 80s. When cleaning out a garage back in the late 90s, I threw out several old arcade video games (She Who Must Be Obeyed had commanded it), and the stickers had fallen off all the EPROMs.

I'm sure that if there were a safety issue with the windowed versions cost wouldn't have been an issue.

I doubt that "auxilliary deisel generator control rooms" have still much to do with the reactor.

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