Up till now whenever I heard "tritium" it was invariably in context of nuclear fusion, be it a bomb of a reactor experiment.

So when I saw an ad for a watch powered by tritium, I went "WTH?!"

Turns out they're not quite "powered by tritium," actually.

www.uniquewatchguide.com/tritium-watches.html

At what they want for them, those watches should be nuclear powered...

Actually, you can power watches with tritium. You use the same technology as the hands, but with enough tritium to make it quite bright, and then line the inside of the capsule with photovolatics. Expensive, impractical and not much power, but it has been done experimentally.

Hmm, possible, but I'd bet it would only work with a LCD display s that takes less power than a mechanical action.