Fast Breeder Reactor

FBR / SFR · Gen IV · First operated: 1951

Uses fast neutrons with no moderator - and "breeds" more fissile fuel than it consumes by converting uranium-238 into plutonium-239.

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0.1%Global share

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4Units operating

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~550°COperating temp

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~40%Thermal efficiency

01 How It Works

Fast reactors use no moderator - neutrons travel at high speed without being slowed. This means they can fission U-238 (not just the rare U-235), and the neutron surplus converts the surrounding U-238 blanket into Pu-239 - producing more fuel than consumed. Liquid sodium metal is used as coolant (no moderator effect, excellent heat transfer). A fast breeder could theoretically extract 60× more energy from uranium than thermal reactors, solving fuel scarcity for millennia.

02 Pros & Cons

✓ Advantages

Breeds more fuel than it consumes
Can use depleted uranium and spent nuclear fuel
Enormous fuel resource multiplication
Can "burn" long-lived radioactive waste

✗ Disadvantages

Liquid sodium reacts violently with water and air
Sodium becomes radioactive (Na-24)
Complex engineering - very few built successfully
High construction cost

03 Specifications

THERMAL EFFICIENCY~40%

OPERATING TEMP~550°C

PRESSURENear atmospheric (Na)

FUELPlutonium / depleted uranium

COUNTRIESRussia, China, India (experimental)

04 Did You Know?

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Russia's BN-800 fast reactor at Beloyarsk has successfully operated since 2016, burning weapons-grade plutonium as fuel. Russia's BN-1200 is under construction. India is building a 500 MWe prototype fast breeder reactor at Kalpakkam.