BN-600 reactor

The BN-600 reactor is a sodium-cooled fast breeder reactor, built at the Beloyarsk Nuclear Power Station, in Zarechny, Sverdlovsk Oblast, Russia. It has a 600 MWe gross capacity and a 560 MWe net capacity, provided to the Middle Urals power grid. It has been in operation since 1980 and represents an improvement to the preceding BN-350 reactor. In 2014, its larger sister reactor, the BN-800 reactor, began operation. The plant is a pool type LMFBR, where the reactor, coolant pumps, intermediate heat exchangers and associated piping are all located in a common liquid sodium pool. The reactor system is housed in a concrete rectilinear building and provided with filtration and gas containment. In the first 24 years of operations, there have been 12 water-into-sodium leaks in the steam generators, routinely addressed by isolating the faulty module with gate valves. These incidents did not have off-site impact, did not generate radioactive material (sodium in the secondary circuit is not neutron-activated) and were not reported to IAEA, since they were deemed to have no impact on safety. As of 2022, the cumulative "energy Availability factor" recorded by the IAEA was 76.3%. The reactor core is 1.03 metres (3 ft 5 in) tall with a diameter of 2.05 metres (6 ft 9 in). It has 369 fuel assemblies, mounted vertically; each consists of 127 fuel rods enriched to between 17–26% 235U. In comparison, normal enrichment in other Russian reactors is between 3–4% 235U. The control and scram system is composed of 27 reactivity control elements including 19 shimming rods, two automatic control rods, and six automatic emergency shut-down rods. On-power refueling equipment allows for charging the core with fresh fuel assemblies, repositioning and turning the fuel assemblies within the reactor, and changing control and scram system elements remotely. The unit employs a three-circuit...