Ya'll Nibbiars S5 is a new design with powerful reactor don't make wrong assumptions. SSN class will probabaly have the same reactors. And for referrence see the SSN around the world which shares the similar reactors with the SSBN counterparts.
Ya'll Nibbiars
1 . The INS Aright has a more powerful reactor. Don't believe the same reactor power as the INS Arihant.
2 . A 190 MW reactor is in development when will be in service don't knew.