What is the Nuclear Fuel Cycle?
The Nuclear Fuel Cycle is the sequence of processes a material must undergo to be used for nuclear power generation in nuclear power reactors. The cycle starts with initial extraction of the nuclear material from the ground and ends with either final disposal or reprocessing.
Steps in the Nuclear Fuel Cycle
Though there are two types of nuclear fuel cycle, open and closed, they share similar steps. Use the sliders to explore!
What is an Open Nuclear Fuel Cycle?
An Open Nuclear Fuel Cycle is a linear sequence of processes, with fuel mined, used and eventually disposed – following a period of interim storage.
Steps in an Open Nuclear Fuel Cycle
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Has the UK ever used an open nuclear fuel cycle?
Currently, the UK operates an open fuel cycle for its generating nuclear power stations (the AGR and PWR reactors).
At the moment, used fuel (known as spent fuel) is being interim stored – either on the same site as the power station or at the Sellafield site in Cumbria.
Eventually, the UK plans to permanently dispose of all High Level Waste (HLW), including spent fuel, in a Geological Disposal Facility (GDF) – once this has been developed by Nuclear Waste Services.
What is a Closed Nuclear Fuel Cycle?
A Closed Nuclear Fuel Cycle is a cyclical process where after fuel is mined and used, it is then reprocessed for reuse.
Steps in an Closed Nuclear Fuel Cycle
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Has the UK ever used a closed nuclear fuel cycle?
Magnox Reactors
The UK operated a closed fuel cycle for its now retired Magnox Reactors (first generation nuclear power stations).
The Magnox fuel from these reactors was reprocessed at the Magnox Reprocessing plant at the Sellafield site in Cumbria. It was not possible to operate an open fuel cycle for Magnox fuel because the Magnox cladding on the fuel rods is vulnerable to corrosion, especially if stored in cooling ponds.
Advanced Gas-cooled Reactors
The Advanced Gas-Cooled Reactors (AGRs), the UK’s second-generation nuclear power reactors, were previously run on a closed fuel cycle, with fuel reprocessed at the Thermal Oxide Reprocessing Plant (ThORP) in Sellafield until 2018. The UK has now adopted an open fuel cycle for spent AGR fuel. This is due to the affordability of mined uranium and concerns regarding the possibility of proliferation of plutonium.
Pressurised Water Reactors
The UK operates an open fuel cycle for its first Pressurised Water Reactor (PWR) at Sizewell B, and will operate an open fuel cycle for future PWRs (such as Hinkley Point C). Initially spent fuel is stored in spent fuel ponds on site, before being transferred to a dry fuel store, also on site.
Open vs Closed?
An open fuel cycle increases the amount of uranium mined from the ground, depleting this natural resource. As used fuel is not reprocessed, it must be disposed of – increasing the volume of high level waste. The UK does not currently have a solution in which this can be disposed of, but is looking to develop a Geological Disposal Facility (GDF).
In contrast, a closed fuel cycle decreases natural resource use. However, at the current time, reprocessing is more expensive than mining due to uranium being a relatively abundant natural resource. On a more positive note, reprocessing decreases the volume of waste products – only 3% of spent fuel is high level waste (the fission products) – the uranium and plutonium can be reused!
Explore Further
Choose from the articles below to continue learning about nuclear.
Uranium – An Indispensable Part of Nuclear Energy
Nuclear Fuel Cycle – Enrichment
Nuclear Fuel Cycle – Reactor Fuel
Did you know? Explore Nuclear also offers great careers information and learning resources.
Below you can find references to the information and images used on this page.
Content References
- IAEA – Nuclear Fuel Cycle
- NSAN – Graduate Awareness in Nuclear (GAIN) Courses
- Nuclear Engineering International – Sizewell Builds Dry Spent Nuclear Fuel Store
- UK Government – Civil nuclear: roadmap to 2050
- US DOE – Nuclear Fuel Cycle
- US NRC – Stages of the Nuclear Fuel Cycle
- World Nuclear Association – Nuclear Fuel Cycle Overview
- World Nuclear News – A guide: Uranium and the nuclear fuel cycle
Image References
- AGR fuel pin, about 1958-1982 – Science Museum Group – CC BY-NC-SA 4.0, © The Board of Trustees of the Science Museum
- Uranium Mining Site – Peter Waggit / IAEA – CC BY-SA 2.0
- Yellowcake inside a Barrel – Dean Calma / IAEA – CC BY-SA 2.0
- Yellowcake Barrels – Dean Calma / IAEA – CC BY-SA 2.0
- Gas Centrifuges – US NRC – CC BY 2.0
- Uranium Dioxide Powder – Chemolunatic – CC BY-SA 4.0
- Torness Nuclear Power Station – Taras – CC BY-SA 4.0
- CLAB, Central Interim Storage Facility for Spent Nuclear Fuel, Oskarshamn, Sweden – Dean Calma / IAEA – CC BY-SA 2.0
- Sellafield – Raymond Knapman / Geograph – CC BY-SA 2.0
- Low Level Waste Repository, Drigg – UK Government – Open Government Licence v3.0
- Chapelcross Power Station – John – CC BY-SA 3.0
- Heysham Nuclear Power Stations – David Merrett – CC BY 2.0
- Sizewell B Power Station – Simon James – CC BY-SA 2.0
