Indian keep falling into the trap of reinventing the wheel and that is why they keep failing despite more resources. The news about 8 submarines from China and this rumour about reactor is not a coincidence. The hull or the kit for the hull for the Pakistani nuke sub will be of Chinese origin, which will be mated to Pakistani reactor and missiles. There is no international treaty that prohibits that. In fact France and Brazil has similar arrangements. Further, after some delays, the Ship Lift and Transfer System at Karachi Shipyard, which itself is nearly a million dollar project is underway, which will allow for much quicker construction of ships and subs. At least two of the subs will not come with AIP engine and will be fitted with Pakistani reactors which will give a timeline of operationalizing a fully loaded Nuke sub of 3 to 5 years. Not the 25 year Indians took to get their Arirhant.