 | This article needs to be updated.(October 2017) |
The Toshiba 4S (Ultra super safe, Small and Simple) is a micro sodium reactor design.
| This article needs to be updated.(October 2017) |
The Toshiba 4S (Ultra super safe, Small and Simple) is a micro sodium reactor design.
The plant design is developed by a partnership that includes Toshiba and the Central Research Institute of Electric Power Industry (CRIEPI) of Japan. [1]
The technical specifications of the 4S reactor are unique in the nuclear industry. [2] The actual reactor would be located in a sealed, cylindrical vault 30 m (98 ft) underground, while the building above ground would be 22×16×11 m (72×52.5×36 ft) in size. This power plant is designed to provide 10 megawatts of electrical power with a 50 MW version available in the future. [3]
The 4S is a fast neutron sodium reactor. It uses neutron reflector panels around the perimeter to maintain neutron density. These reflector panels replace complicated control rods, yet keep the ability to shut down the nuclear reaction in case of an emergency. Additionally, the Toshiba 4S utilizes liquid sodium as a coolant, allowing the reactor to operate 200 degrees hotter than if it used water. [ clarification needed ] Although water would readily boil at these temperatures, sodium remains a liquid; the sodium coolant therefore exerts very low pressure on the reactor vessel even at extremely high temperatures. [ citation needed ]
The Toshiba 4S Nuclear Battery was proposed as the power source for the Galena Nuclear Power Plant in Alaska, but the project was abandoned in 2011 and Toshiba did not proceed with an application for certification of the design. [4]
A research team including Allison Macfarlane and Rodney C. Ewing evaluated waste production of a number of small nuclear reactors, including the 4s, and published their findings in Proceedings of the National Academy of Sciences of the United States of America . They found that small modular reactors produce more radioactive waste than conventional reactors. These claims were contested by NuScale Power. [5]
A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat from nuclear fission is passed to a working fluid, which in turn runs through steam turbines. These either drive a ship's propellers or turn electrical generators' shafts. Nuclear generated steam in principle can be used for industrial process heat or for district heating. Some reactors are used to produce isotopes for medical and industrial use, or for production of weapons-grade plutonium. As of early 2019, the IAEA reports there are 454 nuclear power reactors and 226 nuclear research reactors in operation around the world.
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A sodium-cooled fast reactor is a fast neutron reactor cooled by liquid sodium.
The BN-600 reactor is a sodium-cooled fast breeder reactor, built at the Beloyarsk Nuclear Power Station, in Zarechny, Sverdlovsk Oblast, Russia. Designed to generate electrical power of 600 MW in total, the plant dispatches 560 MW to the Middle Urals power grid. It has been in operation since 1980 and represents an evolution on the preceding BN-350 reactor. In 2014, its larger sister reactor, the BN-800 reactor began operation.
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