No it isn't. All current nuclear waste models purely rely on geology and perfect engineering and assume that 100 to 300 years in the future those sites need zero staff, zero maintenance and zero monitoring.

Which is of course a "cool" assumption to make if you're profiting from this being the conclusion today. Critics of these models (like me) are sceptical of that overly opportunistic conclusion, especially since the timeframes involved are so long and the storage still needs to be maintained long after the profits stopped for one reason or another. I am not saying that this can't be done, I say the current models are insufficient and rely on future generations "dealing with it" somehow.

If you can convince me my worry is unfounded, I'd be happy to hear why I am worrying too much or why we can be certain that this works out as we wish it would.

So what if it's not perfect? Worst case of nuclear waste mishandling would still have milder repercussions compared to doubled, or tripled or worse CO2 levels we are subjecting future generations to. That will persist too long after profits from fossils stop.

Hard to discuss or persuade when you are comparing everything to some ideal, and one-sidedly moreover. Can we talk about real world alternatives. Hypothetically even doubling natural radioactivity background (and that would require total recklessness) would be better option if we could have avoided large part of CO2 output. Now nuclear is becoming moot as we have cheap renewables and batteries anyway.