[beders]

"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"

And

https://apnews.com/article/559da885ca7c3f6252d67e400e92a846

So not exactly an "incredible" safety record, more like an incredibly secret record.