Magnox is a type of nuclear power / production reactor that was designed to run on natural uranium with graphite as the moderator and carbon dioxide gas as the heat exchange coolant. It belongs to the wider class of gas-cooled reactors. The name comes from the magnesium-aluminium alloy (called Magnesium non-oxidising), used to clad the fuel rods inside the reactor. Like most other "Generation I nuclear reactors", the Magnox was designed with the dual purpose of producing electrical power and plutonium-239 for the nascent nuclear weapons programme in Britain. The name refers specifically to the United Kingdom design but is sometimes used generically to refer to any similar reactor.
As with other plutonium-producing reactors, conserving neutrons is a key element of the design. In magnox, the neutrons are moderated in large blocks of graphite. The efficiency of graphite as a moderator allows the Magnox to run using natural uranium fuel, in contrast with the more common commercial light-water reactor which requires slightly enriched uranium. Graphite oxidizes readily in air, so the core is cooled with CO2, which is then pumped into a heat exchanger to generate steam to drive conventional steam turbine equipment for power production. The core is open on one end, so fuel elements can be added or removed while the reactor is still running.
The "dual use" capability of the Magnox design led to the UK building up a large stockpile of fuel grade/"reactor grade" plutonium, with the aid of the B205 reprocessing facility. The low-to-interim burnup feature of the reactor design would become responsible for changes to US regulatory classifications after the US–UK "Reactor-grade" plutonium detonation test of the 1960s. Despite improvements to the design in later decades as electricity generation became the primary operational aim, magnox reactors were never capable of competing with the higher efficiency and higher fuel "burnup" of pressurised water reactors.
In total, only a few dozen reactors of this type were constructed, most of them in the UK from the 1950s to the 1970s, with very few exported to other countries. The first magnox reactor to come online was Calder Hall (at the Sellafield site) in 1956, frequently regarded as the world's first commercial nuclear power station,[1] while the last in Britain to shut down was Reactor 1 in Wylfa (on Anglesey) in 2015. As of 2016[update], North Korea remains the only operator to continue using Magnox style reactors, at the Yongbyon Nuclear Scientific Research Center. The Magnox design was superseded by the Advanced Gas-cooled Reactor, which is similarly cooled but includes changes to improve its economic performance.
^Humphrys, John (2011). A Day That Shook the World : First Nuclear Power Station 1956. British Pathe. Retrieved 2 January 2023.
Magnox is a type of nuclear power / production reactor that was designed to run on natural uranium with graphite as the moderator and carbon dioxide gas...
Magnox Ltd was a wholly-owned subsidiary of the Nuclear Decommissioning Authority (NDA), responsible for the safe decommissioning of 12 British nuclear...
The Magnox Reprocessing Plant is a former nuclear reprocessing facility at Sellafield in northern England, which operated from 1964 to 2022. The plant...
production of Plutonium for weapons. 750 tonnes fuel per year Magnox: 1964–2022 – Magnox national reactor fleet fuel reprocessing Thermal Oxide Reprocessing...
April 2023 - Dounreay joins Magnox Ltd 31 October 2023 - Magnox rebranded as NRS (Registered company name remains Magnox Ltd) 2 April 2024 - Company legally...
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Wylfa nuclear power station (Welsh: Atomfa'r Wylfa) is a Magnox nuclear power station undergoing decommissioning. Wylfa is situated west of Cemaes Bay...
Hunterston A nuclear power station is a former Magnox nuclear power station located at Hunterston in Ayrshire, Scotland, adjacent to Hunterston B. The...
Trawsfynydd nuclear power station (Welsh: Atomfa Trawsfynydd) is a former Magnox nuclear power station situated in Snowdonia National Park in Gwynedd, Wales...
Hinkley Point A nuclear power station is a former Magnox nuclear power station. It is located on a 19.4-hectare (48-acre) site in Somerset on the Bristol...
Dungeness headland in the south of Kent, England. Dungeness A is a legacy Magnox power station consisting of two 250 MWe reactors which were connected to...
Calder Hall Nuclear Power Station is a former Magnox nuclear power station at Sellafield in Cumbria in North West England. Calder Hall was the world's...
the Magnox sites, were not attractive for commercial operations and remained in public ownership as Magnox Electric. On 30 January 1998, Magnox Electric...
small fishing village of Sizewell in Suffolk, England. Sizewell A, with two Magnox reactors, is now in the process of being decommissioned. Sizewell B has...
control of the NDA since April 2016. Magnox Ltd previously two separate site licence companies), manages ten Magnox nuclear power stations and the Harwell...
Altagonum magnox is a species of ground beetle in the subfamily Carabinae. It was described by Darlington in 1952. Darlington, Jr., P. J. (1952). "The...
remaining Magnox reactors remained in public ownership as Magnox Electric. On 30 January 1998 Magnox Electric was merged into BNFL as BNFL Magnox Generation...
Oldbury nuclear power station is a Magnox nuclear power station undergoing decommissioning. It is located on the south bank of the River Severn close to...
Chapelcross nuclear power station is a former Magnox nuclear power station undergoing decommissioning. It is located in Annan in Dumfries and Galloway...
magnesium with small amount of aluminium and other metals for the now-obsolete Magnox reactors. Cladding prevents radioactive fission fragments from escaping...
Berkeley nuclear power station is a former Magnox nuclear power station situated on the bank of the River Severn in Gloucestershire, England. The ongoing...
power station technology. The major installations include all aspects of a Magnox nuclear reactor fuel cycle, based on the use of natural uranium fuel: a...
Bradwell nuclear power station is a Magnox-design nuclear power station that is undergoing decommissioning. It is located on the Dengie peninsula at the...
In June 2007 the company took over operation and management of several Magnox atomic plants from British Nuclear Fuels plc in the United Kingdom through...