China currently has about twelve nuclear subs in operation (six each of Type 93 SSNs and Type 094 SSBNs) but their track record with nuclear subs since the 1970s has been dismal. The early Chinese SSNs were very noisy, easy for Western sensors to detect, unreliable and radioactively dangerous to their crews. Each new Chinese nuclear sub class was successively quieter, more reliable and safer, a development method favored by the Chinese. Their SSNs rarely go to sea, which is one reason they have had no nuclear accidents. Chinese SSBNs (ballistic missile carrying nuclear subs) are basically enlarged SSNs and only recently began carrying out regular combat patrols rather than brief training missions. The six Types 094 Jin-class SSBNs now carry twelve of the improved JL-3 SLBM (sea launched ballistic missiles), which have a range of 10,000 kilometers.
It took nearly a decade of planning, construction, and tinkering to get the first Chinese nuclear sub, the Type 91 Long March No. 1, into service back in 1974. The first SSN was definitely a learning experience, not entering service until the mid-1980s. The Type 91s are small (4,100 tons) as far as SSN’s go and have a crew of about 75 sailors. French sonar was installed, and a lot of the other electronics came from foreign suppliers. Radiation leaks and general unreliability made these boats, which entered service in the 1970s, much feared by Chinese sailors. In the 1980s it was thought the Chinese would just scrap this class but they kept repairing and updating them. The 91s are hopelessly out of date but five were built. Two have been retired and one of those is being turned into a museum ship. The 91s rarely went to sea, although that has changed recently. Apparently the 091s are being used for training crews, a task that is unaffected by the inability of these noisy boats to stay hidden when submerged.
Their first generation Chinese SSBN, the 6,500 ton 092 entered service in the early 1980s. The design was familiar, as it was a stretched version of the 091 class SSNs. The 92 SSBNs had only four missile tubes and rarely went to sea. The Chinese spent a lot of time developing solutions to all these problems, before building the following 93 and 94 classes.
The Type 93 class SSNs began to appear in 2002. This class was also obsolete at birth, and the first of the new Type 95 class was expected to enter service in 2015. That has not happened and little is known about how this new class is being developed. The “Type 95” launched in 2010 turned out to be another Type 93 and, like other boats in that class, looked different than the previous Type 93.
The basic shape of the Type 93s is a lot like the three-decade old Russian Victor III class. The subsequent Type 94 SSBN looks like a Victor III with a missile compartment added. Taking an SSN design and adding extra compartments to hold the ballistic missiles is an old trick, pioneered by the United States in the 1950s to produce the first SSBNs. The Chinese appear to have done the same thing with their new SSN, creating a larger SSBN boat of 9,000 tons displacement. Priority was apparently given to construction of the Type 94, as having nuclear missiles able to reach the United States gives China more diplomatic clout than some new SSNs. Despite all the money and effort put into SSBNs, the Chinese couldn’t arm them with reliable SLBMs for many years. That appears to have changed in 2020 with a successful test of the Chinese JL-3 SLBM. There were more test launches before the JL-3 entered service and effective Chinese SSBNs were available to threaten the United States.
China was apparently underwhelmed by the performance of Type 93 class SSNs. Not much more was expected from the 94 SSBNs. The 93s are too noisy and have a long list of more minor defects as well. The Chinese have had a hard time building reliable nuclear subs, but they are determined to acquire the needed skills. You do that by building more and more new subs while eating your mistakes. The U.S. believes that if China develops SSN and SSBN designs nearly as effective as Western models they will build a lot of them. Thus, by the 2040s China could have the most powerful navy in the world. Meanwhile, China is still a minor naval power once you take into account its small nuclear submarine force.