The Koeberg nuclear plant near Cape Town requires about thirty tons of uranium fuel per year. Unlike a fuel such as coal, this uranium is not burnt up. It undergoes a nuclear reaction, which transforms it into other elements, some of which are highly radioactive. Burning or any other chemical process does not reduce the radioactivity.
That means that over thirty tons of spent nuclear fuel (SNF) are removed from the reactors each year. So far over a million kilograms of this SNF (over 2000 fuel elements) have accumulated since Koeberg began operating in 1984.