Trump's cuts to USAID are projected to kill 700,000 children every year (https://newsroom.ucla.edu/stories/USAID-cuts-global-impact-14-million-deaths). And that's just one of the things he's done.
But why bring up Trump in this thread at all? The post is about a Senator's speech and Trump isn't mentioned in the linked article.
In the past. Earth no longer has enough of the applicable isotope for them to happen. But it's cool we found evidence at least one existed! https://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor