We have only non-classified information to suggest their safety record is spotless. Considering the experiences on Antarctica and Greenland with naval-inspired designs, an entire lack of reported failures really indicates lack of reports, not lack of failures.
When it comes to reactor accidents, there is a limit to what can be covered up. And nuclear accidents from other branches of the military are publicly known; particularly, the US Army blew up a test reactor (SL-1), the USAF has lost some nuclear bombs. Either the USN is uniquely effective at covering up their fuckups, or they really do have an exemplary safety record. My money is on the later.
"While reactor accidents have not sunk any U.S. Navy ships or submarines, two nuclear-powered submarines, USS Thresher and USS Scorpion were lost at sea. The condition of these reactors has not been publicly released"
Yes, but they're far less cost efficient than diesel. That's why the nuclear cruisers were retired. For the carriers and especially the subs the nuclear plants provide operational capacity that diesel can't match. For a research station that's not a concern.
Of course, but those externalities are for more expensive/less cost efficient when discussing uranium and nuclear power than anything involving diesel. Personnel training, fuel production, equipment maintenance, pick an angle to inspect and you'll find the nuclear solution is far more expensive than traditional power plants.
Cost of operation isn't an externality. Externalities are costs we don't directly pay for, like carbon emissions causing global warming. Fossil fuels have incalculably higher externalities in this regard.
You are talking about direct costs that are priced in, and I actually disagree about including personnel and training costs in this specific instance because they are all - to an extent - fungible in the military or navy, as there is no shortage of souls and people will be trained for something for some duration of time.
We have only non-classified information to suggest their safety record is spotless. Considering the experiences on Antarctica and Greenland with naval-inspired designs, an entire lack of reported failures really indicates lack of reports, not lack of failures.