Two earlier reactors were constructed at Beloyarsk: an AMB-100 reactor and an AMB-200 reactor. Both were supercritical water reactors; the first unit used 67 tons of uranium enriched to 1.8%, while the second unit used 50 tons of uranium enriched to 3.0%. The first unit had an indirect steam cycle, while the second had a direct one. Although they were comparable in power to the Shippingport Atomic Power Station, the Soviet planners regarded the Beloyarsk reactors as prototypes. Their main novelty was the use of superheated steam ran through a standard turbine thus resulting in a better efficiency compared to the earlier Obninsk Nuclear Power Plantpilot plant. The first Beloyarsk unit produced about 285 MW heat of which about 100 MW were converted to electricity. The second unit, which used two turbines, had a similar conversion efficiency of about 36%.
Later reactors
Two reactors are now in operation: a BN-600fast breeder reactor, generating 600 MWe gross and a BN-800 fast breeder reactor, generating 885 MWe gross. The BN-800 is the largest fast neutron power reactor in service in the world. Three turbines are connected to the BN-600 reactor. The BN-600 reactor core is tall and has a diameter of. It has 369 fuel assemblies, each consisting of 127 fuel rods with an enrichment of 17–26% 235U. In comparison, typical enrichment in other Russian reactors is in the range of 3–4% 235U. BN-600 reactors use liquid sodium as a coolant. As with most Russian nuclear power plants, the station lacks a containment building. Construction started on the larger BN-800 fast breeder reactor in 1987. Protests halted progress in 1988, but work resumed in 1992 following an order by President Boris Yeltsin. Financial difficulties resulted in slow progress. Construction costs have been estimated at 1 trillion rubles and the new reactor was expected to be finished in 2012–2015. The BN-600 was originally planned to be decommissioned in 2010 but its lifetime was expected to be extended to cover the gap; it has been operating since 1980. On 27 June 2014, controlled nuclear fission started in the BN-800 fast breeder reactor. The newest reactor helps to close the nuclear fuel cycle and to achieve a fuel cycle without or with less nuclear waste. Russia was, at the date, the only country that operates fast neutron reactors for energy production. However issues detected during low power operation required further fuel development work. On 31 July 2015, the unit again achieved minimum controlled power again, at 0.13% of rated power. Commercial operations are expected to start before the end of 2016, now with a power rating of 789 MWe. In December 2015, Unit 4 was connected to the national grid.
