submarine internal propulsion system

nuclear submarine that pulls in sea water in the front 

and inside submarine heats or otherwise energizes that sea water with energy from the nuclear reactor to accelerate sea water 

and in the back expels that sea water to create propulsion of submarine 

submarine that pulls in sea water in the front 

and inside submarine uses a turbine inside submarine to accelerate sea water 

and in the back expels that sea water to create propulsion of submarine 

or more likely a combination of those two above concepts 

because turbine / energy propulsion system is inside submarine, 

that would make submarine more quiet