I am not so sure about that most nuclear power plant run between 50MW to 100 MW Don't forget this is a big boat 7000 ton almost one and half of Type 54 ships. That is why they need compact genset to save on space and this is the first time too since previous boat propeller are connected directly to ST via gear reducer. Nuclear sub require high reliability which almost impossible with single turbine. Single point failure. You can calculate thatI think one 20MW class generator is enough. As I mentioned in post #29, for comparison Virginia class is around the same displacement of 093 and probably 095, it has 30MW shaft power. 40MW would make a sub of that dimension even faster but also noisier. 30MW is good enough. 20MW class is in reality more than that. If my guess in post #29 is close to reality, it is 27MW flat shaft power with max power being 29MW in a dash. That is exactly where Virginia is, and very likely where PLAN wants to be.
Another thing is the room/footprint. 2 means double the weight and footprint, something the sub can not afford.
India launched its first nuclear submarine in 2009, the 6000 dwt Arihant SSBN, with a single 85 MW PWR fuelled by HEU (critical in August 2013) driving a 70 MW steam turbine. It is reported to have cost US$ 2.9 billion and was to be commissioned in 2016. The second and slightly larger Arihant-class SSBN, the INS Aridaman is being built at the Ship Building Centre in Visakhapatnam, and was due to be launched in 2018 and commissioned by 2022. It will have a more powerful reactor. Another three Arihant-class vessels launched by 2023 and then six SSBN twice the size of Arihant-class and six nuclear SSNs are planned, the latter being approved by the government in February 2015. The SSNs will be a similar size to Arihant-class SSBN and powered by a new reactor being developed by BARC. India is also leasing an almost-new 7900 dwt (12,770 tonne submerged) Russian Akula-II class nuclear attack submarine for ten years from 2010, at a cost of US$ 650 million: the INS Chakra, formerly Nerpa. It has a single 190 MWt VM-5/OK-659B (or OK-650B) PWR driving a 32 MW steam turbine and two 2 MWe turbogenerators.
Sturgeon class has 2 steam turbine connected to single propeller
Model of USS Sturgeon (SSN-637)
Nuclear-powered Fast Attack Submarine Sturgeon was the first of a 37-boat class commissioned from March 1967 to August 1975. She was 292 feet (89 m) long and displaced 4,762 tons submerged. Her crew numbered 107. Power came from a single S5W (Submarine, Model 5, Westinghouse) pressurized-water nuclear reactor driving two steam turbines connected to a single propeller shaft. Sturgeon could make better than 20 knots (37 km/hr) on the surface, over 25 knots (46 km/hr) submerged (the exact figure remains classified).