Supporting Information on Waste Packages
This page provides introductory information on waste packages for the geological disposal of higher activity radioactive waste in the UK.
Suitable and safe waste packages are vital to the management of Higher Activity Waste in the UK. They will play a key role in protecting people and the environment during:
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Interim storage at waste packager sites
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Transport to a GDF
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Disposal operations within a GDF
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After closure of a GDF
Waste packages must satisfy the high-level requirements presented in the Disposal System Specification Part A and Part B. These require the packages to provide:
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Safety functions, for instance containment of hazardous materials and shielding from harmful radiation
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Design functions, for instance package dimensions and handling features
The waste package must continue to meet the safety and design functions over time and therefore longer-term processes are also considered in their design and manufacture. For example, corrosion of the waste container or waste materials within the container can lead to gas releases. These gases could be toxic, flammable or radioactive and so must be considered.
A waste package consists of a waste container and the waste within it. While some wastes can safely be containerised with minimal treatment, others need to be processed into a “wasteform” to aid containment and minimise changes to the properties of the container contents over time. Typically we also include the wasteform in the definition of a waste package. The wasteform is the physical and chemical form in which the waste is packaged in the waste container. This may include any waste conditioning material such as grout or resin to bind the waste such that it can be more easily contained, or sand infill to restrict movement and fill voids as shown in the unencapsulated waste package image. The wasteform may also contain other items such as paddles used to mix the fluid waste with conditioning material.
The lid and container walls will create a seal over the package, and a method of lifting to transport the waste package. Depending on the properties of the waste inside it, the waste package may also have a cap, that is, a layer of grout beneath the lid, to improve containment, and a vent to prevent a build up of gasses. These features are illustrated in the figure below.
The diagram above shows the components of an encapsulated waste package, including the container, wasteform, cap, lid, vent and method of lifting.
The diagram above shows the various components of an unencapsulated waste package, including the container, waste, sand infill and lid.
The waste container and the wasteform both contribute to the performance of a waste package. The relative importance of the two components vary from one type of waste package to another and it is the overall performance of the waste package that is assessed. A robust wasteform has less reliance on the container, whereas a more robust container allows for a less robust wasteform.
The chart above shows the relative contributions of the waste container and wasteform to waste package performance. A robust wasteform has less reliance on the container. A more robust container is required for a less robust wasteform.
See the links below for information on how Waste Package Specifications are applied to waste packages for safe management of all types of waste going to a geological disposal site:
Managing Higher Activity Radioactive Waste
Application of Waste Packaging Specifications for Low Heat Generating Waste
Application of Waste Package Specifications for High Heat Generating Waste