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History of the UK Nuclear Sector

The existence of a nuclear industry in the UK originates with scientific discoveries of global significance.

Our story starts with...

The Discovery of the Atom

The birth of the nuclear industry would not have been possible were it not for the discovery of the atom by Democritus in 460 BC.

Henri Becquerel then discovered radioactivity in 1896.

Then, in 1905, a revelation by Einstein: E = mc2 –  small amounts of matter can be converted into large amounts of energy.

The Discovery of Nuclear Fission

1939 was a pivotal year in the discovery of nuclear fission…

…Because this was when nuclear fission was first demonstrated experimentally by Hahn and Strassman, using uranium (U).

The concept of a chain reaction which could generate lots of energy was also explained in 1939, by Meitner and Frisch.

Also in 1939, Bohr and Wheeler began to understand the importance of slow neutrons and isotopes when it came to fission.

This was followed by Perrin’s discovery of critical mass – the minimum amount of nuclear fuel required to sustain a nuclear chain reaction.

In 1942, Enrico Fermi created the first man-made nuclear fission reactor – Chicago Pile 1, USA.

And then the development of the UK nuclear industry began…

The Development of the Nuclear Industry

Military ORIGINS

1940s

MAUD Report
The Maud Committee publish two reports, covering the possibility of using uranium as a source of power and as a weapon.
1941
Manhattan Project
The Manhattan Project, led by the USA with the support of Canada and the UK, comprised research and development undertaken to produce the first nuclear weapons, during WW2.
1942
The Trinity Test
The Trinity Test, on 16 July 1945, was the first detonation of a nuclear weapon. Subsequently, the first atomic bombs were dropped on Hiroshima (6 August 1945) and Nagasaki (9 August 1945).
1945
Atomic Energy Research Establishment
On 1 January 1946, the Ministry of Supply established the Atomic Energy Research Establishment (AERE) at RAF Harwell, under the UK Atomic Energy Act 1946.
1946

Military to Civil

1950s

Windscale Piles
On the site of the former Sellafield Ordnance Factory, Windscale Pile 1 began operations to produce plutonium; Windscale Pile 2 followed in 1951. Their fuel (natural uranium) was produced at the Springfields site.
1950
Civil Nuclear Programme
The UK Government announced that the country would pursue a civil nuclear programme, using nuclear fission to generate electricity.
1953
Atoms for Peace
In a speech, US President Eisenhower proposed “Atoms for Peace” – that nuclear research and development should be reoriented from military to civil (electricity generation) purposes.
1953
The Birth of Fusion?
The Zero Energy Thermonuclear Assembly (ZETA) commenced research operations at the UK’s Atomic Energy Research Establishment (AERE). Operating until 1958, this represented a major experiment in the early history of fusion research – the largest and most powerful fusion reactor in the world at the time.
1954
UK Atomic Energy Authority
The UK Atomic Energy Act 1954 established the UK Atomic Energy Authority (UKAEA), overseeing a research and development programme to develop nuclear reactor technologies and an atomic weapon deterrent.
1954
Calder Hall
On 17 October 1956 Queen Elizabeth opened the first full-scale Nuclear Power Station in the world, a Magnox Reactor at Calder Hall. Workington in Cumbria became the first town to be powered by nuclear energy.
1956
International Atomic Energy Agency
Following President Eisenhower’s “Atoms for Peace” speech in 1953, the International Atomic Energy Agency (IAEA) was established to promote the safe, secure and peaceful application of nuclear science and technology.
1957
Windscale Fire
On 10 October 1957 a fire was discovered in Windscale Pile 1, having already been burning for two days. The fire, an INES Level 5 event, was extinguished on 12 October and is Britain’s worst nuclear incident.
1957
Nuclear Installations Act
Learning from the Windscale Fire, the Nuclear Installations (Learning & Insurance) Act - NIA 1959 - established the requirement for nuclear site licencing and provided for the appointment of inspectors to the Nuclear Installations Inspectorate – regulating nuclear safety.
1959
Nuclear Reactors
In 1959 Chapelcross, the second first generation (Magnox) reactor, was connected to the grid. Also, construction began at Trawsfynydd (Magnox) and the Dounreay Fast Reactor began operations.
1959

Nuclear for Power

1960s

Nuclear Installations Inspectorate
Following NIA 1959, the Nuclear Installations Inspectorate (NII) was formed in 1960 with responsibilities for licencing, inspection and regulation of nuclear sites.
1960
Magnox Reactors
Throughout the 1960s, eight more first generation (Magnox) reactors were connected to the grid: Berkeley (1962), Bradwell (1962), Hunterston A (1964), Hinkley Point A (1965), Trawsfynydd (1965), Dungeness A (1966), Sizewell A (1966) and Oldbury (1968).
1960s
Windscale Advanced Gas-Cooled Reactor
The Windscale Advanced Gas-Cooled Reactor (WAGR), a prototype of the UK’s second generation reactor design (AGRs), supplied electricity to the grid between 1963 and 1981.
1963
Magnox Reprocessing
The Magnox Reprocessing Plant commences operations at what would later become the Sellafield site, with the purpose of reprocessing all spent Magnox fuel as part of the Magnox Operating Programme.
1964
Nuclear Installations Act
The Nuclear Installations Act 1965 (NIA 1965) established the current regulatory regime for the UK nuclear industry, including nuclear site licencing.
1965
Advanced Gas-Cooled Reactors
The construction of the UK’s first second generation nuclear reactor, an Advanced Gas-Cooled Reactor (AGR), begins at Dungeness B.
1966
Non-Proliferation Treaty
The Non-Proliferation Treaty (NPT) represents an agreement to use civil nuclear material for peaceful purposes only, and establishes the five declared nuclear weapons states (China, France, Russia, UK, USA).
1968

A New Generation

1970s

Wylfa
The final first generation (Magnox) reactor is commissioned at Wylfa, Anglesey. Wylfa is a significant evolution of the first Magnox reactor at Calder Hall and can be considered a prototype to the first second generation (AGR) design.
1971
BNFL
British Nuclear Fuels Limited (BNFL, headquartered in Risley, Warrington) established to develop, manage and operate UK nuclear fuel cycle facilities – Calder Hall, Chapelcross, Capenhurst, Springfields, Magnox Reprocessing.
1972
Health and Safety at Work Act
The Health and Safety at Work etc Act 1974 (HSWA 1974) provides the legal framework that underpins the regulation of the nuclear industry alongside The Nuclear Installations Act (NIA) 1965 and The Energy Act (TEA) 2013.
1974
Advanced Gas-Cooled Reactors
Hinkley Point B and Hunterston B are the first of the UK’s second generation nuclear reactor (AGRs) to be connected to the grid and start generating electricity.
1976
Three Mile Island
At Three Mile Island Power Station (Pensylvania, USA), a cooling valve malfunction led to a partial core melt of reactor 2. The event, an INES Level 5 incident, had no adverse injuries or health effects.
1979
Institute of Nuclear Power Operators
In response to the Three Mile Island incident, the Institute of Nuclear Power Operators (INPO) was created in the USA to promote excellent in the operation of nuclear power plants.
1979

Changing Times

1980s

Sellafield
In 1981, the BNFL-owned portion of the Windscale and Calder Works were renamed as Sellafield. The remainder of the site, owned by UKAEA, continued to be known as Windscale.
1981
Sizewell B Public Inquiry
In January 1983, a public inquiry began into the construction of the UK’s first Pressurised Water Reactor (PWR) at Sizewell B. Hearing 340 days of evidence this was, at the time, the UK’s longest inquiry in history.
1983
JET
The Joint European Torus (JET) reactor commences operations, achieving its first plasma on 25 June 1983. Ultimately, in 1991, JET would become the first experiment to produce controlled fusion power.
1983
Chernobyl
On 26 April 1986, a steam explosion and fire destroyed Reactor 4 at the Chernobyl Power Plant in Ukraine. This event, an INES Level 7 incident, resulted from a flawed design and poor nuclear safety culture and remains the worst accident in the history of the nuclear industry.
1986
WANO
In response to the Chernobyl incident, the World Association of Nuclear Operators (WANO) was created to work together to maximise the safety and reliability of nuclear power plants.
1989
The end of the UK Nuclear Age?
A policy review by Margaret Thatcher’s conservative government ultimately led to the shelving of the then-planned PWRs at Hinkley Point C, Sizewell C and Wylfa B.
1989
Magnox Decommissioning
Berkeley became the first Magnox station to enter decommissioning in 1989, with its two units ceasing power generation in 1988 and 1989 respectively. This marked the start of the Magnox Decommissioning Programme.
1989

Privatisation

1990s

ThORP
The Thermal Oxide Reprocessing Plant (ThORP) commenced operations at Sellafield, reprocessing spent oxide fuel from the UK’s AGR and PWR fleet and abroad (with customers including the Japanese).
1994
Sizewell B
Sizewell B, the UK’s first Pressurised Water Reactor (PWR), is connected to the grid and starts generating electricity.
1995
British Energy
British Energy was established in 1995 and privatised in 1996, taking ownership of the UK’s AGR and PWR stations.
1996
Marine Protection
The UK signed the OSPAR Convention for protection of the marine environment of the North East Atlantic; restrictions on radioactive discharges would ultimately contribute to the end of reprocessing.
1997
Tokaimura
At a small fuel production facility adjacent to the Tokai Nuclear Power Plant in Japan, a criticality accident occurred on 30 September 1999 due to aggregation of enriched uranium. This INES Level 4 incident resulted in the exposure of three workers to high doses.
1999

A New Framework

2000s

Nuclear Industry Security Regulations
The Nuclear Industry Security Regulations 2003 (NISR 2003) provides the legal framework that underpins the security regulation of the nuclear industry, including the requirement for approved site security plans.
2003
Calder Hall Decommissioning
After 44 years of operations, Calder Hall ceases generating electricity. At the time, this first Magnox station held the record for the longest operating nuclear reactor.
2003
Civil Nuclear Police Authority
Under the Energy Act 2004, the Civil Nuclear Police Authority (CNPA) were created to oversee the Civil Nuclear Constabulary (CNC) and meet the policing needs of the UK’s nuclear licenced sites.
2004
Nuclear Decommissioning Authority
On 1 April 2005 the Nuclear Decommissioning Authority (NDA) commenced its functions under the Energy Act 2004 with the mission to clean-up the UK’s earliest nuclear sites safely, securely and cost effectively. Sites on the NDA Estate include Sellafield, Dounreay and the Magnox sites.
2005
New Nuclear
A 2008 Government White Paper formally backs development of a new generation of nuclear power stations, identifying eight potential sites in 2009 and establishing the Generic Design Assessment (GDA) process.
2008
EDF
EDF purchases British Energy, including the UK’s seven operating AGRs and one operating PWR.
2009

Transition

2010s

Fukushima
On 11 March 2011, a 15-metre tsunami led to the failure of the power supply and cooling to three reactors at Fukushima Daiichi, Japan. This event, an INES Level 7 incident, did not result in any deaths.
2011
New Nuclear
In 2012 NNB GenCo, a consortium of EDF and CGN, were granted a nuclear site licence to install two EPR reactors (a type of Pressurised Water Reactor, PWR) at Hinkley Point C.
2012
Office for Nuclear Regulation
On 1 April 2014, the Office for Nuclear Regulation (ONR) were established as an independent regulator under The Energy Act 2013 (TEA 13) to regulate nuclear safety, site health and safety, security, safeguards and transport.
2014
The Final Magnox Reactor
Wylfa became the final Magnox station to enter decommissioning, with its two units ceasing power generation in 2015 (Reactor 1) and 2012 (Reactor 2) respectively. This marked the end of the Magnox Operating Programme.
2015
Hinkley Point C
In 2017 construction of two EPR reactors (a type of Pressurised Water Reactor, PWR) begins at Hinkley Point C – marking a new generation of nuclear development in the UK.
2017
Ionising Radiation Regulations
The Ionising Radiation Regulations 2017 (IRR 2017) impose limits on the exposure of employees to ionising radiation.
2017

The Dawn of a New Era?

2020s

Decommissioning
Magnox Ltd (now Nuclear Restoration Services) agree to decommission the UK’s second generation reactor fleet, the Advanced Gas-Cooled Reactors (AGRs) – each to be transferred from EDF following defueling, after 2025.
2021
AGR Decommissioning
On 7 June 2021, it was announced that Dungeness B will be the first Advanced Gas-Cooled Reactor (AGR) to permanently cease electricity generation. Hunterston B and Hinkley Point B follow during 2022.
2021
A Fusion Breakthrough?
On 21 December 2021, UKAEA researchers at the Joint European Torus (JET) reactor in Oxfordshire achieved 59 MJ energy from fusion sustained over five seconds – more than double the previous record (set by JET in 1997).
2021
End of Reprocessing
In July 2022, the Magnox Reprocessing Plant at Sellafield ceased operations for the final time. Following the closure of ThORP in 2018, this marked the end of reprocessing in the UK and a shift to an open fuel cycle policy.
2022
Great British Nuclear
During July 2023, the UK Government launched Great British Nuclear (GBN) to drive expansion of the nuclear sector in the UK and achieve 24 GW of nuclear electricity supply to the grid by 2050. GBN have thus launched competition funding for Small Modular Reactors (SMRs) and Advanced Nuclear Technologies (ANTs).
2023
Hinkley Point C
During 2027 - 2028 commissioning of two EPR reactors (a type of Pressurised Water Reactor, PWR) is expected to take place at Hinkley Point C – marking a new generation of nuclear electricity generation in the UK.
2028

To find out more about the key events that shaped the development of the nuclear industry in the UK and across the globe, why not check out our dedicated page?

Events that shaped Nuclear

Adam Piatt

Graduate Awareness in Nuclear (GAIN) Course, NSAN

Outline History of Nuclear Energy, World Nuclear Association

United Kingdom, World Nuclear Association

Nuclear Development in the United Kingdom, World Nuclear Association

Safety of Nuclear Power Reactors, World Nuclear Association

Safeguards to Prevent Nuclear Proliferation, World Nuclear Association

Three Mile Island, World Nuclear Association

Chernobyl, World Nuclear Association

Fukushima Daiichi, World Nuclear Association

Nuclear Fusion Power, World Nuclear Association

History of Nuclear Timeline, Gov.UK

On This Day 1956: Queen Switches on Nuclear Power, BBC

Windscale Piles: Cockcroft’s Follies avoided nuclear disaster, BBC

Licensing Nuclear Installations, ONR

History, IAEA

Records of the Inspectorate of Nuclear Installations and successors, The National Archives

Dungeness B, EDF Energy

Legal Framework & Regulations, ONR

History, INPO

Sizewell B Power Station Inquiry Report, UK Parliament

Our History, WANO

Our Mission, WANO

Magnox Reprocessing Plant Achieves Final Milestone, Gov.UK

Civil Nuclear Police Authority, Gov.UK

About the Nuclear Decommissioning Authority, Gov.UK

Energy Act 2004, Legislation.Gov.UK

Nuclear Regulatory Review, UK Parliament

Hinkley Point C, ONR

Ionising Radiation Regulations (NS-INSP-GD-054), ONR

Operations to end at Sellafield’s Magnox Reprocessing Plant, Gov.UK

AGR Decommissioning Factsheet, Gov.UK.

Jet Makes History Again, ITER

JET, CCFE

The First Page of the MAUD Report, UK Government – Public Domain

Los Alamos: Oppenheimer, Groves & Sproul – Courtesy of Los Alamos National Laboratory

Unless otherwise indicated, this information has been authored by an employee or employees of the Los Alamos National Security, LLC (LANS), operator of the Los Alamos National Laboratory under Contract No. DE-AC52-06NA25396 with the U.S. Department of Energy. The U.S. Government has rights to use, reproduce, and distribute this information. The public may copy and use this information without charge, provided that this Notice and any statement of authorship are reproduced on all copies. Neither the Government nor LANS makes any warranty, express or implied, or assumes any liability or responsibility for the use of this information.

Trinity Test, US DOE – Public Domain

Aerial View of Rutherford Appleton Laboratory, Science & Technology Facilities Council – Licence CC BY-SA 2.0 DEED

Windscale Piles, US DOE – Public Domain

Croxall Rapeseed Fields in Staffordshire, Bs0u10e0 – Licence CC BY-SA 2.0 DEED

Atoms for Peace U.S. postage stamp (from 1955), US Post Office – Public Domain

ZETA Reactor, UK Government – Public Domain

Dounreay: Fission on the North Coast, shirokazan – Licence CC BY 2.0 DEED

Calder Hall Nuclear Power Station (after opening), UK Government – United Kingdom Open Government Licence v3.0

Vienna International Centre, Rodolfo Quevenco / IAEA – Licence CC BY-SA 2.0 DEED

Windscale Piles (1990), Sellafield Ltd – Licence CC BY-SA 2.0 DEED

A View of the Sellafield Site (2014), Tom Anderson – Licence CC BY 2.0 DEED

Chapelcross Nuclear Power Station, John – Licence CC BY-SA 3.0 DEED

IAEA Safeguards Inspectors, US AEC / IAEA – Licence CC BY-SA 2.0 DEED

Trawsfynydd Power Stations Old and New, Andrew – Licence CC BY 2.0 DEED

Decommissioning of the Windscale Advanced Gas-cooled Reactor in Sellafield, IAEA – Licence CC BY-SA 2.0 DEED

Magnox Reprocessing Plant, Gov.UK – Licence CC0 1.0 DEED

Bradwell, Terryjoyce – Licence CC BY-SA 3.0 DEED

Dungeness B Power Station, Sandpiper – Public Domain

Earth Day, PX – Public Domain

Wylfa Nuclear Power Station (from above), UK Government Agencies – United Kingdom Open Government Licence v3.0

Aerial View of Sellafield, Simon Ledingham / Geograph – Licence CC BY-SA 2.0 DEED

Building Dundee, Neil Williamson – Licence CC BY-SA 2.0 DEED

Hunterston B Nuclear Power Station, Linear-Vertex – Licence CC BY-SA 4.0 DEED

Exelon Three Mile Nuclear Island Generating Station, Constellation Energy – Licence CC BY-SA 4.0 DEED

Vogtle Electric Generating Plant, NRC – Public Domain

Sizewell B Aerial Image, John Fielding – Licence CC BY 2.0 DEED

JET Vacuum Vessel, EUROfusion – Licence CC BY 4.0 DEED

Aerial View of Chernobyl Nuclear Power Plant with Sarcophagus, Vadim Mouchkin / IAEA – Licence CC BY-SA 2.0 DEED

Dungeness Power Stations, John K Thorne – Public Domain

Sizewell A and B Nuclear Power Stations, Ted and Jen – Licence CC BY 2.0 DEED

Berkeley Power Station, Robert Powell – Licence CC BY-SA 3.0 DEED

Sellafield Viewed from Railway Line (ThORP), Raymond Knapman / Geograph – Licence CC BY-SA 2.0 DEED

Sizewell B Power Station, Simon James – Licence CC BY-SA 2.0 DEED

Hinkley Point B Reactors, Mark Robinson – Licence CC BY 2.0 DEED

Evening Colors on the Atlantic Coast, Hervé Simon – Licence CC BY-SA 2.0 DEED

Tokai Nuclear Power Plant, US DOE – Public Domain

Nuclear Security Fence / Barriers, NRC – Licence CC BY 2.0 DEED

Calder Hall Tower Demolition, UK Government Agencies – United Kingdom Open Government Licence v3.0

Civil Nuclear Constabulary Škoda Kodiaq, Douglas Sinclair – Licence CC BY 2.0 DEED

Torness Nuclear Power Plant, Alessandro Ambrosetti – Licence CC BY 2.0 DEED

Meeting the Energy Challenge: A White Paper on Nuclear Power, UK Government / Gov.UK – Public Domain

Torness Nuclear Power Station (April 2016), Taras Young – Licence CC BY-SA 4.0 DEED

Fukushima Daiichi, Tokyo Electric Power Co. (TEPCO) – Licence CC BY-SA 2.0 DEED

Hinkley Point C (Visualisation), Gov.UK – United Kingdom Open Government Licence v3.0

West Somerset: Hinkley Point B Power Station, Lewis Clarke / Geograph – Licence CC BY-SA 2.0 DEED

Wylfa Power Station, Reading Tom – Licence CC BY 2.0 DEED

Hinkley Point C, Brett Jordan – Licence CC BY 2.0 DEED

Radon Decay in a Cloud Chamber, Nuledo – Licence CC BY-SA 4.0 DEED

Heysham Nuclear Power Stations, David Merrett – Licence CC BY 2.0 DEED

JET Vessel Internal View, EUROfusion – Licence CC BY 4.0 DEED

NASA Goes to the Olympics, NASA Earth Observatory – Licence CC BY 2.0 DEED

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