NS RWM8 key terms

Materials contaminated with radionuclides at concentrations above clearance levels, for which no further use is foreseen. It requires management and disposal under regulatory control to protect people and the environment.

The time required for half the atoms of a particular radionuclide to decay. It determines how long waste remains hazardous and influences storage and disposal options.

Radioactive waste with limited radioactivity, often suitable for near-surface disposal. It may include contaminated clothing, tools, and filters, and typically requires containment but not shielding.

Waste with radioactivity levels requiring shielding and more robust containment than low-level waste, but not generating significant heat. It is often encapsulated and placed in engineered facilities.

Highly radioactive waste, typically from reprocessing spent fuel, that generates significant heat. It requires shielding, cooling, and disposal in deep geological formations.

Specified requirements that a waste package must meet for a particular storage or disposal facility. They cover radionuclide inventory, chemical composition, package strength, and other properties.

The process of determining the physical, chemical, and radiological properties of waste. It informs classification, processing, packaging, and safety assessments.

Separating waste into categories based on radioactivity, chemical hazards, or disposal route. It prevents cross-contamination and reduces the volume requiring specialised treatment.

Techniques such as compaction, incineration, or evaporation that decrease the physical volume of waste. This lowers storage and disposal costs and conserves facility capacity.

Converting waste into a stable, solid form suitable for transport, storage, or disposal. It often involves immobilising waste in cement, glass, or bitumen.

A conditioning method in which waste is surrounded or embedded in a solid matrix, such as cement or grout, inside a container. It limits radionuclide release.

A process that incorporates high-level waste into a glass matrix by melting and cooling. The glass immobilises radionuclides and is highly durable.

The process of fixing radionuclides within a solid matrix to prevent their release. It is a key step in waste conditioning.

Fuel that has been irradiated in a reactor and is no longer efficient for generating power. It is highly radioactive and may be treated as waste or reprocessed.

A chemical process that separates reusable uranium and plutonium from spent fuel. It produces high-level waste and requires stringent safeguards.

The regulatory process of releasing waste or materials from nuclear controls because their radioactivity is below specified levels. Cleared material can be recycled or disposed of conventionally.

Radioactive waste that meets regulatory criteria for exemption from some or all nuclear licensing requirements because the hazard is very low.

The process of safely closing and dismantling a nuclear facility. It generates large volumes of waste that must be characterised and managed.

Land containing radionuclides above background levels due to past activities. It may require remediation to protect health and the environment.

A long-term waste management option in which waste is placed deep underground in stable rock formations. Engineered and natural barriers isolate radionuclides from the biosphere.

Man-made components such as waste forms, containers, and backfill that prevent or delay radionuclide release from a disposal facility. They work with natural barriers.

A safety approach that uses several independent barriers, both engineered and natural, to isolate waste. If one barrier fails, others continue to limit release.

A structured argument and supporting evidence demonstrating that a facility is safe during operation and after closure. It covers normal conditions and accident scenarios.

An analysis that estimates how a disposal system will behave over long timescales, including radionuclide release and transport. It supports the safety case.

The movement of radioactive atoms through engineered barriers, groundwater, and rock. Understanding it is essential for predicting long-term doses.

The part of the environment where living organisms exist, including soil, water, and air. In disposal assessments, it is where humans and ecosystems could be exposed.

The maximum permitted radiation dose to a person from regulated practices. It is set by regulatory bodies to protect workers and the public.

A principle requiring radiation risks to be reduced until further reduction is grossly disproportionate to the benefit. It applies to nuclear facilities.

A disposal option for low- and intermediate-level waste in engineered trenches or vaults a few metres to tens of metres below ground. It relies on containment and institutional control.

A disposal method for small volumes of radioactive waste in deep, narrow boreholes. It is being considered for disused sealed sources and other limited inventories.

Regulatory or administrative measures applied after a disposal facility closes, such as land-use restrictions and monitoring. They last for a defined period.

A government body responsible for licensing and supervising nuclear facilities and radioactive waste management. It sets safety requirements and enforces compliance.

An international treaty on the safety of spent fuel management and radioactive waste management. It promotes high safety standards and peer review.

Containers designed to protect radioactive contents during transport and withstand accidents. They must meet international safety standards.

Heat produced by radioactive decay in waste. For high-level waste, it influences storage and disposal design because it can affect temperature and barrier performance.

A record or estimate of the quantities and types of radionuclides in a waste stream or facility. It is essential for safety assessments and safeguards.