My point remains: is there any actual safety concern with putting nuclear waste underground other than potential groundwater pollution if the containment casks get perforated (which can be avoided by not burying waste where there's groundwater)?
The only scenarios that people have presented in which nuclear waste could result in contamination are borderline absurd, like if humanity hypothetically loses all records of where waste is buried along with knowledge of what radiation is and some future civilization might dig up the waste canisters and crack them open.
Nothing in your link covers the safety or dangers of waste disposal beyond the vague statement that, "There is general agreement that placing spent nuclear fuel in repositories hundreds of meters below the surface would be safer than indefinite storage of spent fuel on the surface." That article is a couple paragraphs on waste containers, and a list of different countries' waste management schemes. It doesn't dig into any long term risk assessment.
The only scenarios that people have presented in which nuclear waste could result in contamination are borderline absurd, like if humanity hypothetically loses all records of where waste is buried along with knowledge of what radiation is and some future civilization might dig up the waste canisters and crack them open.