In Russia, a utility model of a large missile submarine with an auxiliary low-power nuclear unit has been registered. The development will solve the main problem of classic diesel-electric submarines (DES) — the need to surface regularly to recharge their batteries.
The new design reduces this limitation and lowers the risk of detection. In the new project, the submarine receives a compact nuclear unit that continuously generates electricity both on the surface and underwater.
The key difference is a dual-circuit water-organic scheme with a low-pressure reactor. This layout reduces pressure and temperature in the primary circuit, lowers radioactive risks, and makes it possible to reduce the weight and dimensions of the unit. The electric generator of the "mini-atom" works together with the diesels and recharges the batteries without interruptions.
The project also provides for a single propeller shaft with a controllable-pitch propeller. This gives flexible speed control and allows power to be distributed more efficiently between the diesels and the nuclear module.
According to the authors' concept, the revolutionary scheme increases endurance, reduces fuel consumption, and simplifies the layout compared with traditional solutions.
Advanced Project 677 "Lada" DES are famous for their low noise signature, but are forced to surface because of technical nuances of the power plant. The patent solves this problem.