The natural reactors at Oklo and Gabon have been extensively studied.
It's been shown that soil is such a good ion exchange medium, that the
fission products get trapped and don't migrate very far in millions of years -
even though there were absolutely no measures taken to inhibit that
Contrast that with the Yucca Mountain repository - where the waste is
encapsulated in something like borosilicate glass, which is then encased
in steel containers....
The scientific consensus, as opined by the National Academies of
Science and Engineering, from our best Ph.D. level scientists state that
nuclear waste CAN be successfully contained, the opinions of unidentified
Navy reactor operators, nothwithstanding.
Dr. Gregory Greenman