Why does nuclear waste last so long?

reactors, medical equipment and uranium enrichment plants for reactors or weapons present a salad of radioactive materials in their tailings.

There are some of them, with very low half-, but with a large emission of energy and radiation in a short time. These are dangerous than those with a very long half-life, but emit little energy and radiation per unit time. are less dangerous, but last an eternity.

The procedure is to condition and dispose of these wastes properly that they do not contaminate the environment and do not affect human health.