Why does some nuclear radiation take thousands of years to decay and some only a decade or so?

Question

I’ve been researching nuclear energy and radiation in an effort to understand it. I don’t understand why I’m seeing a lot of info saying a nuclear bomb’s radiation dies out in about 10 years, but a nuclear reactor explosion like Chernobyl will take thousands of years. What’s the difference?

EDIT: Okay, so what I’m seeing is I didn’t account for the differences in types and sheer amounts of fuel for each kind of reaction. I’m not a chemist or physicist or anything. I just like learning stuff. 😁

These explanations make a lot of sense, so to those of you who didn’t answer the wrongway and provided helpful and educational responses, thank you.

In: Chemistry

Answer 1

The reason lies in the very word used to describe it . . . RADIATION.

For some atoms, they radiate a LOT, which means they decay quickly.

Others radiate more slowly, and so take longer to decay.