It's not the US Military generally that is held up as an example of nuclear safety, it's specifically the US Navy's track record for operating nuclear reactors. Hanford was a big mess, but that wasn't run by the Navy. Bikini Atoll was bad, but that wasn't caused by a mistake operating a nuclear reactor.
Your supposition that reactor accidents smaller than Chernobyl might be hidden from the public doesn't seem well grounded either; we know the US Army fucked up the operation of the SL-1 reactor, resulting in 3 deaths. Here's a big list of nuclear fuckups: https://en.wikipedia.org/wiki/List_of_military_nuclear_accid... Some of those severe, some minor. I don't see much reason to believe that substantial naval reactor incidents have been omitted from that list. Such accidents are hard to hide from long, particularly if it means a bunch of sailors got irradiated or a ship had to be taken out of service for decontamination / repair. The incidents on that list bracket the sort of mystery accident you're supposing; it lists accidents much less severe and much more severe.
> Your supposition that reactor accidents smaller than Chernobyl might be hidden from the public doesn't seem well grounded either.
I supposed no such thing. You don’t need an accident to leave a mess (as evidenced by our current climate crisis). You just need to be negligent of the environment and surrounding population center. The US military (including the Navy) has a terrible track record when it comes to environmental issues around its military bases around the world. My supposition is that they are simply equally inconsiderate with their nuclear logistics as they are with their other operations. And Bikini Atoll is my ground for thinking so.
That list of military nuclear accidents was interesting. My impression is that the rate of accidents dropped off quickly over time. Maybe the military got better at handling nuclear material? Maybe some other explanation?
Your supposition that reactor accidents smaller than Chernobyl might be hidden from the public doesn't seem well grounded either; we know the US Army fucked up the operation of the SL-1 reactor, resulting in 3 deaths. Here's a big list of nuclear fuckups: https://en.wikipedia.org/wiki/List_of_military_nuclear_accid... Some of those severe, some minor. I don't see much reason to believe that substantial naval reactor incidents have been omitted from that list. Such accidents are hard to hide from long, particularly if it means a bunch of sailors got irradiated or a ship had to be taken out of service for decontamination / repair. The incidents on that list bracket the sort of mystery accident you're supposing; it lists accidents much less severe and much more severe.