The BREST reactor is a Russian conceptual design for a lead-cooled fast reactor based on a generation IV reactor. Two designs are planned, the BREST-300 (300 MWe) and the BREST-1200 (1200 MWe). The main characteristics of the BREST reactor are passive safety and a closed fuel cycle.^[1]

The reactor uses nitride uranium-plutonium fuel, is a breeder reactor and can burn long-term radioactive waste. Lead is chosen as a coolant for being high-boiling, radiation-resistant, low-activated and at atmospheric pressure.^[2]

BREST-300

The construction of the BREST-300-OD in Seversk (near Tomsk) was approved in August 2016.^[3][4] The preparatory construction work commenced in May 2020.^[5] Construction started in 8 June 2021.^[6][7]

The first BREST-300 will be a demonstration unit, as forerunner to the BREST-1200.

The combination of a heat-conducting nitride fuel and the properties of the lead coolant allow for complete plutonium breeding inside the core. This results in a small operating reactivity margin and enables power operation without prompt neutron reactor power excursions. In simpler terms, the uranium 238 in the core is converted to plutonium, which itself will undergo an effective fission in the fast spectrum. This is in contrast to other fast reactor designs, where an outside blanket of uranium is required; placing too much uranium in the core section would lead to subcritical operation.^{[clarification needed]} In doing so, a substantial number of neutrons is required for breeding. This implies in turn, that in the reactor operation, there are "just enough" neutrons to operate, and no excess is present.^{[clarification needed]}

Technical data

• Thermal power: 700 MW
• Electrical power 300 MW
• Average lead coolant temperature: 540 °C (1,004 °F) on entry in the steam generator; 340 °C (644 °F) on exit of the steam generator
• Loop number: 4
• Core height: 1,100 millimetres (43 in)
• Fuel load: 20.6 short tons (18.7 t)
• Fuel campaign: 5 years