Description

The physical, chemical, and biological characteristics and properties of the containers at the time of emplacement in the repository.

Category

Categorisation as a Feature, Event and/or Process.

  • Features are physical components of the disposal system and environment being assessed. Examples include waste packaging, backfill, surface soils. Features typically interact with one another via processes and in some cases events.
  • Events are dynamic interactions among features that occur over time periods that are short compared to the safety assessment timeframe such as a gas explosion or meteorite impact.
  • "Processes" are issues or dynamic interactions among features that generally occur over a significant proportion of the safety assessment timeframe and may occur over the whole of this timeframe. Events and processes may be coupled to one another (i.e. may influence one another).

The classification of a FEP as an event or process depends upon the assessment context, because the classification is undertaken with reference to an assessment timeframe. In this generic IFEP List, many IFEPs are classified as both Events and Processes; users will need to decide which of these classifications is relevant to their context and its timeframes.

  • Feature

Relevance to Performance and Safety

The “Relevance to Performance and Safety” field contains an explanation of how the IFEP might influence the performance and safety of the disposal system under consideration through its impact on the evolution of the repository system and on the release, migration and/or uptake of repository-derived contaminants.

The relevance of container characteristics and properties to repository performance and safety will depend upon the disposal concept being evaluated. Some concepts require a container to have a long-term containment function (e.g. in some disposal concepts for spent fuel), but other concepts do not need long-term containment (e.g. in many disposal concepts for LLW). The characteristics and properties of a waste container will determine whether it completely prevents the migration of radionuclides and other contaminants from the waste form immediately after repository closure. If there is complete containment initially, the container’s physical, chemical and biological characteristics and properties will determine whether containment is lost subsequently during the assessment period and if so, when this occurs. An assessment will need to assess the significance for safety and performance of mechanical and chemical interactions between different container components (e.g. internal structures such as iron inserts that are placed within copper canisters for spent fuel in some disposal concepts) and between the container, the waste form and barriers that surround the container. The chemical and biological characteristics and properties of the container will also affect the chemical environment of the waste form and surrounding barriers, which may in turn influence the release of radionuclides and other contaminants from the waste form and their subsequent mobility and/or retardation. The mechanical strength of a container may be relevant to repository performance and safety; for example if it is necessary to maintain the integrity of the containers as they are loaded by other containers being stacked on them.

2000 List

A reference to the related FEP(s) within the 2000 NEA IFEP List.

2.1.03

Related References

  • IAEA (), Containers for Packaging of Solid Low and Intermediate Level Radioactive Wastes, IAEA Technical Report Series TRS-355, International Atomic Energy Agency, Vienna
  • IAEA (), Characterisation of Radioactive Waste Forms and Packages, IAEA Technical Report Series TRS-383, International Atomic Energy Agency, Vienna