There are different types of nuclear waste. Alot of it comes from the reactor itself. Other types are created from material coated in radioactive substances. Nuclear waste is very toxic. Some types of radioactive waste can take hundreds or even thousands of years to die out. There is no way to safely throw away or dispose of this material. That’s what makes it so dangerous. Most of the nuclear waste that is produced is from fuel rods that are deep with in the reactor.