Sorry, but that seems a bit counter-intuitive...
How can a diesel engine be quieter than a nuclear reactor?
Basically, an electric motor have less parts in motion than a nuclear reactor, thats why they are more silent.
In order to operate a reactor (steam principle) in fact, you need a cooling system that will moove the water exchanging heat; this is accomplished with the pump's help, that generate a higher acustic signature in comparison to a project that doesnt need a cooling system.
Right now there are 3 different 212 projects:
212A (first batch, operated by ITA and GER)
212A (second batch under construction, operated by ITA and GER, also known as 212B)
212S exposrt version exclusive for ISR
If you want details about 212 project, just ask!
And yes, til now its the more silent sub in the world (far from 214)
I forget: 214 is 209's evolution (export sub), 212 its a totally different project that comes from 211 project (israeli "Dolphin").