Asubstance is composed of only one kind of atom and can't be separated into simpler substances or converted into another substance by chemical processes. under which category would you classify this substance?

That substance would be classified as an element

This is what i found “nuclear fuel is material used in nuclear power stations to produce heat to power turbines. heat is created when nuclear fuel undergoes nuclear fission. most nuclear fuels contain heavy fissile actinide elements that are capable of undergoing and sustaining nuclear fission.” i hope this you for what your looking for. can you plz mark me brainliest?