This will be the type 097 class SSN, the follow up to the type 095 class SSN (3rd generation), type 093 SSN (2nd generation), and type 091 SSN (1st generation).
The major improvement should be in noise reduction of the boat.
At the recent 2013 Four Northeastern Provinces Cooperation Leaders' Conference held in Ordos, Inner Mongolia, Tan Zuojun, vice governor of Liaoning Province and former general manager of China State Shipbuilding Corporation, revealed that development of China's fourth-generation nuclear submarines and other high-tech weapons and items of equipment in the Northeastern Provinces of China had been completed. The news drew considerable attention.
The fourth generation nuclear submarine features high performance and low noise level.
Military expert Du Wenlong pointed out that the main characteristic of the fourth generation nuclear submarine would be its high performance. Compared with earlier submarines, modern attack submarines differ significantly in offensive power, possessing both anti-submarine capabilities and also strong potential for anti-ship action and attacks on land-based targets. He pointed out that the fourth generation nuclear submarines of the United States and Russia already have these capabilities; China's fourth-generation nuclear submarines too will be equipped with the appropriate torpedoes, along with missiles suitable for use against other sea-going or land-based targets. In addition, the Chinese submarine will have low noise output, a key indicator for measuring a modern nuclear submarine's underwater survivability, as well as its ability to remain hidden during maneuvers, or undetected while launching a missile attack. He pointed out that the fourth-generation nuclear submarine will possess effective noise damping features, such as a quieter nuclear power reactor with less vibration, and a more advanced hull muffler system, so that it will be difficult to detect even if within range of enemy sonar.
On the question when the fourth-generation nuclear submarine will enter service, Du Wenlong said that completion of development and completion of construction are two different phases - the cycle from completion of development to manufacturing, and then to fitting out and launch, can be long, perhaps several years. Progress is mainly determined by two factors: one is technical indicators, and the other is strategic need. (not sure if China has the urgency to build next SSN).
A significant enhancement of nuclear counterattack capability (this is more SSBN).
Analysts believe that continual development of attack submarines and strategic nuclear submarines at times of peace, adding better performance and greater combat ability, can enhance strategic deterrence capability. China's strategic nuclear forces are weapons to deter third parties from becoming involved in local conflicts. China firmly adheres to the principle of non-first use of nuclear weapons, but the existence of strategic nuclear submarines will give China a stronger voice and more room for maneuver in the case of any crisis. In addition, Song Xiaojun points out that the United States, Russia, Britain and France all possess modern strategic nuclear submarines as a symbol of their status as 'Great Powers'; it is natural that China should be unwilling to lag behind.