I thought nuclear submarine technology was more to do with miniaturization of nuclear reactor and building conventional submarine.
Going by your logicsince China didn't have indigenous designed rifle prior to launching nuclear submarine, hence Chinese first nuclear submarine wasn't successful, thanks for admitting.
You reach the Indian embassy here:
Address
Chancery
2107 Massachusetts Avenue, NW
Washington, DC 20008
Telephone: (202) 939-7000
Fax: (202) 265-4351
And advice our Govt them, I'm sure Indian Govt is in need of consultations from CCP certified nuclear submarine experts.