Look at it this way: When a diesel sub is endangered, they can turn off everything and I mean EVERYTHING. Quiet as a mouse that doesn’t exist. However, it will have to resurface eventually.
A nuclear sub cannot do that. The cooling pumps have to keep running. But they can stay under water pretty much indefinitely (until they run out of food).
Look at it this way: When a diesel sub is endangered, they can turn off everything and I mean EVERYTHING. Quiet as a mouse that doesn’t exist. However, it will have to resurface eventually. A nuclear sub cannot do that. The cooling pumps have to keep running. But they can stay under water pretty much indefinitely (until they run out of food).
I assume the cooling pumps make noise when they’re running?