Recently, there were a rather significant release by Chinese news on the performance of PLAN's first generation nuclear submarines 091 and 092. While these news releases probably don't satisfy the curiosity of many PLA followers waiting to hear about the latest generation of attack subs, I find the release to be quite helpful in understanding PLAN.
One of the things I really enjoyed doing is comparing the 091 program to the CV-16 Liaoning project. Bear in mind, the two programs happened in two different periods of PLAN history. The construction of the first 091 started in the late 60s and the last unit did not launch until 1990. Its development lasted through the political turbulent years of 70s and the decade of military cuts in the 80s. In comparison, the CV-16 development lasted through this past decade when PLAN had its most budgetary and political support for naval power projection.
In spite of all of this, there are also similarities between the two program. In both cases, China had to go alone with almost no help from outside sources. As a result of this, both projects proceeded in a very methodical manner. Aside from the extended research before they start doing work on the ships, land based simulation models were built to help train the crew members. They did not try to do too many things too quickly. For CV-16, they first practised carrier take-off/landing on land based simulation air strip before trying touch-n-go on CV-16 before finally giving each of the original J-15 crew a chance to do take off/landing. In between each steps, PLAN took their time evaluating lessons before moving forward. As we go forward, CV-16 will gradually practice more complicated take-off and landing scenarios in its training process. In the 091 project, the entire test program went through multiple boats. No. 401 went through numerous testing after it joined service in the early 1970s before being forced back to the dry docks for extensive modifications 10 years later and not emerging again until 6 years after that. The long endurance patrol testing that one would expect out of something like an attack sub did not happen until with No. 403 in 1985. Only after No. 404, the first production version of Type 091, was in service did PLAN really finish testing of all the critical mission requirements. In 1988, No. 404 went through deep dive testing to 300 m, submerged torpedo launching tests and sailing at maximum submerged speed of 22 knots. Obviously, the testing period of 091 was very long (over 15 years), but one can see the similar gradual process of expanding on the mission envelope with carrier operations.
The big differences between the two program are obviously the technical preparedness and budgetary constraint of the two programs. China certainly walked into Type 091 project about as technologically limited as one can be in such a strategic program. The first two units were basically test mules that are already decommissioned. Even No. 404 and 405, the production certified units of the class, took 12 to 13 years from laying down to joining service. That's something CV-16 project never had to worry about. China was as ill equipped as one could imagine to start a program like 091 from budgetary, technology and political support point of view. It was as well equipped as it could be for the CV-16 project.
At the same time, looking at the 091 program can also give us clue about the current and future Chinese attack submarines. One of the biggest challenges for the 091 program was getting a safe working nuclear submarine into a submarine at a time when China could not even build its own civilian nuclear plant. One can imagine that the reactors in Type 091 boats experienced its shares of nuclear safety and reliability issues over time. Due to the low efficiency of its generators, Type 091 could only operate at a maximum submerged speed of 22 knots. So I think that the biggest change from Type 091 to 093 was having a safe and reliable reactor that can sustain a much higher submerged speed (say 30 knots). We know that it took 13 years to launch the last unit of Type 091. Let's say that time was cut to half ( 7 years ) fro the lead boat Type 093 class due to improved technology and funding, that would still mean the first unit would've been laid down in the mid 90s. At that time, China's civilian nuclear technology was only able to commission the Qinshan-1 CNP-300 plant employing first generation safety/efficiency. One could imagine that even with improved safety and reliability, these reactors on Type 093 probably weren't very efficient and quiet. The Chinese bbs rumours of pebble bed reactors for 093 are quite ludicrous when one actually thinks about the timelines.
Fortunately for PLAN, China's civilian nuclear industry has made a lot of progress since then. The second generation CNP-600 plants were used in the Qinshan-2 project that were connected to the grid in the early 2000s. With the recent proliferation/localization of CPR-1000 plants, transfer of technology from the AP-1000 project and the development of CAP-1400 power plant, the Chinese civilian industry should be able to design its own 3rd generation nuclear plant in the near future. If we assume that similar progress was made in the military nuclear reactors during the same period in noise level, safety and efficiency, it would reason that quieter and more powerful reactor would be available to power larger submarines. Seeing that the most recent 093B submarine was launch sometimes last year, it could be using a new type of reactor available in the early 2000s that would be a full generation ahead of the ones available for the first two 093s. That could lead to smaller/quieter/more efficient reactors allowing for more space for noise isolation technology and more power available for greater maneuverability. For the next generation of attack submarine (Type 095 class), it should be using a reactor from around 2010 that will be another generation safer and more efficient. If 091 and 093 programs are good indications, the first Type 095 will also likely to be a prototype unit that will have problems resolved in later unit.
Of course, all of that is speculations on my part, but we rarely get new information on China's nuclear submarine force.