For Diesel Subs ,yes it is too noisy.But about INS Arihant .that was a nice joke.Still most influential Think Thanks in India cant get a decent picture of INS Arihant.All they got is a low resolution old picture.And you are saying you got it acoustic signature.They dont even deploy for full time operation.
And our govt is not that dumb to spend 25 years and lot R&D ,money for developing Nuclear Subs.