I have a tritium keychain that I imported from the UK that glows green 24/7. It's great, especially for finding keys in a dark backpack. I wish we could buy them here in the US, but the NRC has recently (in the past 10 years) passed a mandate that radioactive materials cannot be used for novelties. This was surely a "reduce the 'frivolous' approvals the NRC has to deal with"-based measure rather than a safety measure, since the safety risks are essentially zero (see below). Since Japan follows a monkey-see-monkey-do approach to the US with regard to their domestic nuclear regulation, Japan's regulatory agency (METI) surely followed suit and passed the same mandate verbatim.
The keychain is a 40 mm x ~10mm diameter acrylic fob with a 20 mm x ~4 mm phosphor-coated glass tube encased within, which contains maybe 20 micrograms of Hydrogen-3, aka tritium, which is a weak beta emitter. Beta particles are just high energy electrons - they generally don't even pass through the acrylic, and if they did they wouldn't penetrate our skin. I wouldn't recommend chewing and swallowing the glass tube, but then again I wouldn't recommend chewing and swallowing most things currently on my desk.
Yes, I work in the nuclear field in both the US and Japan.:-)
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I have a tritium keychain that I imported from the UK that glows green 24/7. It's great, especially for finding keys in a dark backpack. I wish we could buy them here in the US, but the NRC has recently (in the past 10 years) passed a mandate that radioactive materials cannot be used for novelties. This was surely a "reduce the 'frivolous' approvals the NRC has to deal with"-based measure rather than a safety measure, since the safety risks are essentially zero (see below). Since Japan follows a monkey-see-monkey-do approach to the US with regard to their domestic nuclear regulation, Japan's regulatory agency (METI) surely followed suit and passed the same mandate verbatim.
:-)
The keychain is a 40 mm x ~10mm diameter acrylic fob with a 20 mm x ~4 mm phosphor-coated glass tube encased within, which contains maybe 20 micrograms of Hydrogen-3, aka tritium, which is a weak beta emitter. Beta particles are just high energy electrons - they generally don't even pass through the acrylic, and if they did they wouldn't penetrate our skin. I wouldn't recommend chewing and swallowing the glass tube, but then again I wouldn't recommend chewing and swallowing most things currently on my desk.
Yes, I work in the nuclear field in both the US and Japan.