https://en.wikipedia.org/wiki/USS_Thresher_(SSN-593)#Cause
> After the accident Rickover further reduced plant restart times, which had already been gradually improving with new technology and operating experience, in addition to limiting factors that could cause a shutdown.[26]
The Navy may have done the math and determined the loss of a boat to the enemy is a less bad thing than the loss of a boat to a “nuclear accident”.
I desperately hope for and welcome anyone with experience in the space to correct me.
[1] https://en.wikipedia.org/wiki/Kursk_submarine_disaster
[2] https://www.sciencedirect.com/science/article/abs/pii/S00295...
[3] https://en.wikipedia.org/wiki/Soviet_submarine_K-19
[4] https://www.ebsco.com/research-starters/history/soviet-nucle...
[5] https://gizmodo.com/sunken-soviet-submarine-is-quietly-leaki...
[6] https://en.wikipedia.org/wiki/Submarine_incident_off_Kildin_...
[7] https://en.wikipedia.org/wiki/Submarine_incident_off_Kola_Pe...