Radioactive wastes are produced as a by-product from many important medical, industrial, research and defence activities. In the UK, the majority of radioactive waste is from the decommissioning of nuclear power reactors.
This section looks at radioactive waste produced during the nuclear fuel cycle and radioactive waste produced from medical, industrial, research and defence activities.
Overview of the nuclear fuel cycle
The ‘nuclear fuel cycle’ is the sequence of industrial activities needed to generate electricity by nuclear power. It includes the manufacturing of nuclear fuel and management of spent (used) nuclear fuel. The image below shows the full range of activities in the ‘nuclear fuel cycle’ that produce radioactive waste.
Read the sections below to find out more about the main activities in the nuclear fuel cycle that produce radioactive wastes.
Uranium mining and milling
Uranium mining is the first step in the nuclear fuel cycle.
The mine separates out uranium-bearing minerals from other minerals by crushing and milling the uranium ore. The uranium-rich product is a yellow powder, called ‘yellowcake’ because of its colour. Yellowcake is a uranium oxide and is the raw material for manufacturing nuclear fuel.
Milling produces very large amounts of crushed rock waste, known as ‘tailings’. These are usually collected and stored in large piles and slurry ponds at the mine site.
Areas in Asia, Africa, Canada and Australia have large deposits of uranium ore. Although there are some uranium ore deposits in the UK, they are generally quite small and uneconomic to mine. For this reason, there is no commercial uranium mining or milling in the UK.
Download our factsheet to learn more about uranium mining and milling
Uranium enrichment and fuel manufacture
Uranium mills based overseas transport some of the yellowcake produced from uranium mining and milling to the UK for processing.
Current nuclear power reactor designs in the UK use uranium oxide fuel; however, natural uranium does not contain enough of the uranium-235 isotope needed to power a nuclear reactor. This means an enrichment plant has to process the yellowcake and concentrate the uranium-235. This enrichment process produces ‘depleted uranium’ as a by-product. This is not a waste because of its potential energy value and range of other possible uses.
Next, a conversion facility converts the enriched uranium back to a solid oxide powder. Compressing and baking this powder produces solid fuel pellets. Arranging these pellets into a series of metal rods produces fuel assemblies that are suitable for use in a nuclear reactor.
Fuel manufacture produces relatively small amounts of waste compared to other activities in the nuclear fuel cycle.
Download our factsheet to learn more about uranium enrichment and fuel manufacture
Reactor operations and electricity generation
Newly manufactured fuel assemblies are transported to operating nuclear power reactor sites for loading into the reactor cores. A typical commercial nuclear reactor contains around 100 tonnes of enriched uranium fuel.
During the operation of a nuclear reactor, the amount of uranium-235 reduces until it is no longer economical to continue using the fuel. The spent (used) fuel is typically removed from the reactor and stored in a cooling pond at the reactor site for several months. This allows the heat emitted by the fuel to reduce due to radioactive decay.
At present, spent fuels are safely stored in case there is a need for them in future. If the UK government decides that these materials have no future use, they will reclassify the material as waste. The UK government will make this decision based on economic, environmental and safety grounds.
Routine operations of a nuclear power reactor produce radioactive waste in small amounts. The main operational wastes produced are resins used to clean up liquids, such as cooling pond waters, and contaminated components and protective clothing.
Download our factsheet to learn more about reactor operations and electricity generation
Spent fuel reprocessing
Reprocessing enables the recovery of uranium and plutonium from spent fuel. New fuel can be manufactured from the recovered plutonium and uranium.
Reprocessing spent fuel is a complex process. It involves separating the spent fuel from the metal components of the fuel assemblies. The spent fuel is then dissolved in acid and a chemical separation process is used to recover the uranium and plutonium.
Reprocessing produces a residual acidic liquid, which is highly radioactive. This waste is High Level Waste (HLW) and generates heat. Vitrification is the process used to convert this waste into a stable, solid form for long-term storage. The final canisters containing the solid waste are safely stored at Sellafield until a route for disposing of them becomes available.
Reprocessing and vitrification also produce several other radioactive wastes. These are mainly Intermediate Level Waste (ILW). They include the metal cladding separated from the spent fuel and items such as filters used to clean (‘scrub’) the gases generated.
Download our factsheet to learn more about spent fuel reprocessing
Decommissioning nuclear power facilities
Decommissioning occurs at the end of the operational life of a nuclear reactor or facility. This involves decontaminating and dismantling buildings and their contents. This phase also involves cleaning up any land contamination.
Decommissioning produces large volumes of concrete, brick, steel and soil. Most of this is non-radioactive waste and can be reused or recycled.
Download our factsheet to learn more about decommissioning nuclear power facilities
Radioactive waste from other sectors
In the UK, over 90% of radioactive waste is produced by activities that are part of the nuclear fuel cycle. Much smaller amounts of waste are produced by the medical, industrial, research and defence sectors.
Medical
Radioactive materials are used for many purposes in the medical industry. In particular, radioactive materials are used to sterilise equipment, and help diagnose and treat medical illnesses.
Relatively small amounts of radioactive waste are produced during the manufacture, use and recycling of radiopharmaceuticals. Used radioactive sources are often returned to the manufacturer for recycling.
Download our factsheet to learn more about radioactive wastes from medical activities
Industrial
The industrial sector uses radioactive sources in a number of ways. The most common use is for non-destructive testing of materials and components. For example, gamma rays are used to test the quality of welds or the thickness of products, such as paper.
Download our factsheet to learn more about radioactive wastes from industrial activities
Research
Academic and industrial research using radioactive materials takes place in many universities and research establishments across the UK. This research is very diverse, ranging from developing new radiotherapy treatments to testing novel solid materials for encapsulating liquid radioactive wastes. Some research will produce small amounts of radioactive wastes.
Research into nuclear fusion technology takes place at the Joint European Torus (JET) facility at Culham. Experiments and tests using JET produce small amounts of radioactive waste during its operation.
Download our factsheet to learn more about radioactive wastes from research activities
More information on research and development at the Nuclear Decommissioning Authority
Defence
Radioactive wastes produced by the defence sector arise in three main areas:
- Operation of active nuclear-powered submarines and the decommissioning of retired submarines;
- Clean-up of defence sites that may have been contaminated in the past; and
- Production, management and decommissioning of strategic deterrent nuclear weapons.
The Ministry of Defence is responsible for the safe, secure and sustainable dismantling of retired submarines.
Download our factsheet to learn more about radioactive wastes from defence activities