In the UK, radioactive wastes are classified according to the type and quantity of radioactivity they contain and how much heat is produced.
The information below summarises how radioactive wastes are classified, with examples of typical waste types. The waste category is determined by the level of radioactivity.
Higher Activity Wastes
Higher Activity Waste (HAW) includes High Level Waste (HLW), Intermediate Level Waste (ILW) and some Low Level Waste (LLW) that is unsuitable for disposal in the Low Level Waste Repository (LLWR). HAW arises from activities such as:
- reactor operation
- reprocessing of spent nuclear fuel
- decommissioning
High Level Waste (HLW) is waste where the temperature may rise significantly because of their radioactivity. The design of waste storage or disposal facilities has to take this into consideration.
Less than 1% of all radioactive wastes (by volume) are in the HLW category. HLW is produced as a by-product from reprocessing spent fuel from nuclear reactors. HLW typically occurs in liquid form and a process called ‘vitrification’ converts the liquid HLW into a solid product.
Intermediate Level Waste (ILW) exceeds the upper boundaries for Low Level Waste (see Low Level Waste below) but does not generate a significant amount of heat.
About 6% of all radioactive wastes (by volume) are in the ILW category. The major components of ILW are nuclear reactor components, graphite from reactor cores and sludges from the treatment of radioactive liquid effluents.
Low Level Waste
Low Level Waste (LLW) contains relatively low levels of radioactivity, not exceeding 4 gigabecquerel (GBq) per tonne of alpha activity, or 12 GBq per tonne of beta/gamma activity.
Most LLW comes from the operation and decommissioning of nuclear facilities. The waste includes items such as scrap metal, paper and plastics. Some smaller amounts of LLW also come from hospitals and universities. About 94% of all radioactive wastes (by volume) are in the LLW category.
Some LLW near the radioactive content threshold is managed as Higher Activity Waste (HAW). This may be because it is too difficult to separate from Intermediate Level Waste (ILW) or does not meet the Waste Acceptance Criteria for current LLW disposal facilities (see Higher Activity Wastes above).
Very Low Level Waste (VLLW) is a sub-category of LLW with specific activity limits. Sites that produce VLLW can dispose of the waste with regular household or industrial waste at permitted landfill facilities. The major components of VLLW from nuclear sites are building rubble, soil and steel items. These arise from the dismantling and demolition of nuclear reactors and facilities.
Low Level Waste
Low Level Waste (LLW) contains relatively low levels of radioactivity, not exceeding 4 gigabecquerel (GBq) per tonne of alpha activity, or 12 GBq per tonne of beta/gamma activity.
Most LLW comes from the operation and decommissioning of nuclear facilities. The waste includes items such as scrap metal, paper and plastics. Some smaller amounts of LLW also come from hospitals and universities. About 94% of all radioactive wastes (by volume) are in the LLW category.
Some LLW near the radioactive content threshold is managed as Higher Activity Waste (HAW). This may be because it is too difficult to separate from Intermediate Level Waste (ILW) or does not meet the Waste Acceptance Criteria for current LLW disposal facilities (see Higher Activity Wastes above).
Very Low Level Waste (VLLW) is a sub-category of LLW with specific activity limits. Sites that produce VLLW can dispose of the waste with regular household or industrial waste at permitted landfill facilities. The major components of VLLW from nuclear sites are building rubble, soil and steel items. These arise from the dismantling and demolition of nuclear reactors and facilities.