[lemming]

Sustainable Energy Without The Hot Air (really excellent book, although a little dated now) discusses this:

https://www.withouthotair.com/c24/page_169.shtml

Thus waste storage engineers need to make a plan to secure high-level waste for about 1000 years. Is this a difficult problem? 1000 years is certainly a long time compared with the lifetimes of governments and countries! But the volumes are so small, I feel nuclear waste is only a minor worry, compared with all the other forms of waste we are inflicting on future generations. At 25 ml per year, a lifetime’s worth of high-level nuclear waste would amount to less than 2 litres. Even when we multiply by 60 million people, the lifetime volume of nuclear waste doesn’t sound unmanageable: 105 000 cubic metres. That’s the same volume as 35 olympic swimming pools. If this waste were put in a layer one metre deep, it would occupy just one tenth of a square kilometre.