BN-800 reactor
Russian fast breeder nuclear reactor, operating since 2016
- 3 min read
- 3 chapters
Related on Lably
Through Russia and Chernobyl disaster
Design
The plant is a pool-type liquid-metal-cooled fast breeder reactor (LMFBR), in which the reactor, coolant pumps, intermediate heat exchangers and associated piping are all located in a common liquid sodium pool. This is similar to the general design of EBR-II, which went into service in 1963, but is otherwise significantly different. For example, EBR-II used metallic fuel, whereas BN-800 uses oxide fuel. The design of this plant was started in 1983 and was completely revised in 1987 after the Chernobyl disaster and to a somewhat lesser degree in 1993, according to the new safety guidelines. After the second revision, output power was increased by 10% to 880 MW due to the increased efficiency of the power generator steam turbines.
The reactor core is, in size and mechanical properties, very similar to the BN-600 reactor core, but the fuel composition is not. While BN-600 uses medium-enriched uranium dioxide, this plant burns mixed uranium–plutonium fuel, helping to reduce the weapons-grade plutonium stockpile and provide information about the functioning of the closed uranium-plutonium fuel cycle, which does not require plutonium separation or other chemical processing.
The unit employs a three-circuit coolant arrangement; sodium coolant circulates in both the primary and secondary circuits. Water and steam flow in the third circuit. This heat is transferred from the reactor core via several independent circulation loops. Each is composed of a primary sodium pump, two intermediate heat exchangers, a secondary sodium pump with an expansion tank located upstream, and an emergency pressure discharge tank. These feed a steam generator, which in turn supplies a condensing turbine that turns the generator.
Many infrastructure facilities were designed to accommodate both the BN-800 and a proposed BN-1200 reactor.
Sign in to keep reading
2 more chapters are free with a Lably account.
History
Construction started in 1983 as Unit 4 at the Beloyarsk nuclear power plant. It was put on hold after Chernobyl. It resumed in 2006 and BN-800 achieved minimum controlled power in 2014, but issues led to further fuel development work. On 31 July 2015, the unit achieved minimum controlled power again – 0.13% of rated power. The reactor was connected to the grid in December 2015 and achieved full power for the first time in August 2016. Commercial operation began on 31 October 2016.
In September 2000, the United States and Russia signed the Plutonium Management and Disposition Agreement, under which each country would dispose of at least 34 metric tons of surplus weapons-grade plutonium.
In 2016, the Obama administration proposed ending construction of the US MOX Fuel Fabrication Facility. The construction contract was terminated in October 2018. The administration proposed that the US share of plutonium be diluted with non-radioactive material and disposed of in the underground WIPP facility. However, the dilution could be reversed, and the material reconverted into weapons-grade plutonium.
On 3 October 2016, Russian president Vladimir Putin ordered the agreement to be suspended because the US did not meet its obligations.
In January 2020, the reactor began operating with a new batch of uranium–plutonium mixed-oxide (MOX) fuel. Its initial core already contained MOX alongside uranium oxide.
Rosenergoatom's 2026 operating review describes the transition from a hybrid core to a full MOX core during 2020–2023, with full MOX loading completed in 2023.
Plutonium disposal
The BN-800 could be used to close the fuel cycle. The core load of 15 tons of material consists mostly of U-238 and about 20.5% plutonium. This could be taken from reprocessed spent nuclear fuel assemblies.