Alfa class
Fuel enrichment
90% U-235
HEU
Alfa class is a nuclear-powered submarine operated by Soviet Navy, powered by BM-40A / OK-550 of about 155 MWt. Retired.
Lead-bismuth cooled, titanium hulled, and the fastest submarines ever built. The coolant froze solid if the reactor was allowed to cool, so the boats had to be kept hot continuously in port. An unsuccessful design, and the only serious attempt at a liquid-metal-cooled naval reactor.
Propulsion
| Reactor | BM-40A / OK-550 |
|---|---|
| Reactors per vessel | 1 |
| Thermal output | 155MWt |
| Fuel enrichment | 90% U-235HEU |
| Refuelling | not disclosed |
Vessel
| Category | submarine |
|---|---|
| Role | SSN |
| Operator | Soviet Navy |
| Country | Russia |
| Vessels in class | not stated |
| In service from | 1971 |
| Status | Retired |
Other submarines
| Class | Enrichment | Status |
|---|---|---|
| AUKUS submarines | HEU | Planned |
| Akula class | - | Operating |
| Arihant class | HEU | Operating |
| Astute class | HEU | Operating |
| Borei class | HALEU | Operating |
| Columbia class | HEU | Under construction |
| Dreadnought class | HEU | Under construction |
| Han class (Type 091) | - | Operating |
| Le Triomphant class | LEU | Operating |
| Los Angeles class | HEU | Operating |
| Ohio class | HEU | Operating |
| Oscar II class | - | Operating |
| Seawolf class | HEU | Operating |
| Suffren class (Barracuda) | LEU | Operating |
| Type 093 and 094 (Shang and Jin) | LEU | Operating |
| Typhoon class | - | Retired |
| USS Nautilus | HEU | Retired |
| Vanguard class | - | Operating |
| Virginia class | HEU | Operating |
| Xia class (Type 092) | - | Retired |
| Yasen class | HALEU | Operating |
Sources
- World Nuclear Association, Nuclear-Powered Ships · retrieved 2026-09-07
How these sources are used, including the corrections applied on top of them and what is deliberately left blank · download the underlying data