Sodium-cooled fast reactor

Sodium-cooled fast reactor (SFR) is a type of nuclear reactor that uses sodium as a coolant. The term "fast" refers to the high energy levels of the neutrons in the reactor, which are not moderated, unlike in other types of reactors.

History

The concept of the SFR was first proposed in the 1940s, and the first experimental SFR, the Experimental Breeder Reactor I (EBR-I), was built in the United States in 1951. Since then, several countries, including France, Russia, and Japan, have built and operated SFRs.

Design and operation

The SFR is a type of breeder reactor, which means it can produce more fissile material than it consumes. This is achieved by using a fast neutron spectrum to cause fission in plutonium and other transuranic elements, which are produced from uranium in the reactor.

The coolant in an SFR is liquid sodium, which has several advantages. Sodium has a high thermal conductivity, which allows it to efficiently transfer heat from the reactor core. It also has a high boiling point, which means the reactor can operate at high temperatures without the risk of the coolant boiling. However, sodium reacts violently with water and air, which poses safety challenges.

Safety

Safety is a major concern in the design and operation of SFRs. The violent reaction of sodium with water and air requires that the reactor be designed to prevent any contact between the sodium and these substances. This is typically achieved by using a double-walled design, with the space between the walls filled with an inert gas.

In addition, the high energy levels of the neutrons in the reactor can cause damage to the reactor materials over time. This requires the use of materials that are resistant to neutron damage, and regular maintenance and inspection of the reactor.

Future development

Despite the challenges, SFRs are considered a promising technology for the future of nuclear power. They have the potential to produce large amounts of energy with a small amount of fuel, and to reduce the amount of nuclear waste produced. Several countries, including China and India, are currently developing new SFR designs.