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Fast reactor FBR

A fast reactor (FBR) uses liquid sodium or lead as coolant and no moderator. 2 are operating worldwide, totalling 1.5 GW gross, out of 44 units of this type on record.

Operating
2
1.5 GW gross
Under construction
3
Planned
15
Retired
8
Liquid sodium Sodium Steam Coreno moderator,fast neutrons Intermediateexchanger Steamgenerator Turbineto grid Three loops
A third loop keeps radioactive sodium away from water, because sodium and water react violently.

Deliberately unmoderated. Fast neutrons fission plutonium efficiently and can convert fertile U-238 into more fuel than the reactor consumes, which is the origin of the term breeder. A liquid metal — usually sodium, sometimes lead — carries heat at near-atmospheric pressure, so there is no large pressurised vessel to rupture. Sodium's violent reaction with water and air is the countervailing hazard and has driven most of the operational difficulty in the fleet's history. Russia's BN-600 and BN-800 are the only commercial units with long operating records.

Advantages
  • Can breed more fissile material than it consumes, turning U-238 into fuel and extending uranium resources many times over
  • Can consume long-lived actinides from spent fuel, reducing the waste that needs deep disposal
  • Sodium is liquid at atmospheric pressure, so there is no large pressurised vessel to rupture
  • Very high power density and excellent heat transfer
Drawbacks
  • Sodium burns in air and reacts violently with water, which is why a third loop is needed
  • Sodium is opaque, making in-service inspection and refuelling far harder than in water reactors
  • Needs 15–20% fissile content or plutonium, so HALEU or reprocessing is a prerequisite
  • Long history of sodium leaks and fires; very few units have accumulated long operating records
Design basis
CoolantLiquid sodium or lead
ModeratorNone
Fuel formMixed oxide or metallic fuel
Typical enrichment15–20% fissile, or plutonium
Where they operate
Russia2

Model lines

ModelOperatingUnits on record
Aurora — 7
BN-1200 — 4
Prototype — 2
PRISM — 2
SVBR-100 — 1
SNR-300 — 1
PH-250 — 1
Na-1200 — 1
Liquid Metal FBR — 1
BREST-OD-300 — 1
BN-800 1 1
BN-600 1 1

Operating FBR units

UnitCountryGross MWOnline
Beloyarsk nuclear power plant 4 Russia 885 2016
Beloyarsk nuclear power plant 3 Russia 600 1981

Sources