Significados de unstable isotopes en inglés

Let's say we start with a million unstable isotopes of carbon.

But what if all the available molecular feedstock is contaminated with unstable isotopes?

They require rare radioactive isotopes as fuel, and their by-products are unstable isotopes, which are themselves radioactive and harmful to people.

Unlike physical "systems"-bacteria ,animals ,menand stars-unstableisotopes do not individually have a predictable life span.