So many more mistakes:
Tritium is indeed radioactive with a half life of about 12.5 years (That's why it's great for making glow in the dark dials that require no light recharging or electricity. Only a tiny amount is needed, but a 12.5 year half life is pretty darn "hot" in the vernacular, and if you have a lot of it, you get a lot of energy release. It emits beta rays (high energy electrons) which aren't as much of a problem as gamma, but do cause surface burning, etc.).
U238 is indeed radioactive. It's an alpha particle emitter with a half life of 4.5 billion years. (Agreed, it's not highly radioactive, but it certainly is radioactive. U235 is more highly radioactive.)
I'm hardly an alarmist about nuclear technology and am a strong supporter of nuclear power, but blatant mistakes in your post don't help the argument in favor of it.