Атомная подводная лодка S Álvaro Alberto (SN10)

The Brazilian Navy modernization program plans the development and construction of six nuclear submarines. In the Brazilian doctrine, the raison d'etre of the national defense strategy is to develop deterrence capability against a possible hostile force to the national territory. The country understands that with its future nuclear fleet, at least some of its weapons will be able to survive the first strike of an enemy and prevent further attempts at aggression. Another rationale is to support the defense of the so-called Blue Amazon (Portuguese: A Amazônia Azul), a resource-rich area covering about 4,500,000 km2 (1,700,000 sq mi) off the Brazilian coast. This area is the country's exclusive economic zone, home to a huge diversity of marine species, valuable metallic minerals and other mineral resources, petroleum, and the world's second largest rare-earth reserve.

Álvaro Alberto has many similarities to his conventional predecessor of the Scorpène class. The first Brazilian nuclear submarine will have a beam of 9.8 m (32 ft) to accommodate the pressurized water nuclear reactor (PWR). Its 100 m (330 ft) length and 6,000-ton displacement will be propelled by a 48 MW (64,000 hp) fully-electric propulsion system.

The advantages of an SSN over a conventionally powered SSK are much longer endurance (a nuclear submarine can stay submerged for months and does not need refueling), and higher speed. Unlike most SSKs, SSNs do not have to surface periodically for air, which would compromise their stealth. Their roles include intelligence gathering platforms, insertion and exfiltration of special forces teams in addition to traditional hunter-killer SSN roles. The most prominent roles of the SSNs, is the capability to launch cruise missiles, giving a significant overlap between cruise missile submarines (SSGN) and traditional attack submarines.