Description

The release of contaminants in solid phase from the waste form.

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.

  • Event
  • Process

Comments

The “Comments” field, when present, contains any additional explanation of the IFEP, beyond that implicit in the FEP's description and provided in the “Relevance to Performance and Safety” field. This additional explanation may include, where appropriate, the IFEPs characteristics, the circumstances under which it might be relevant and its relationship to other (especially similar) IFEPs.

This might result from processes such as the fluvial erosion of the repository (FEPs 1.2.8), the glacial erosion of the repository (FEP 1.3.5) or magmatic/volcanic activity affecting the repository (FEP 1.2.5).

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 release of radionuclides and other contaminants in solid form implies physical disruption of the waste form by processes such as fluvial, marine or glacial erosion. The physical nature of the solids (grain size, shape, hardness, density etc.) and the characteristics of the environment into which the release occurs (e.g. whether a sub-aqueous environment or a subaerial environment), will determine the area over which the solids bearing radionuclides and other contaminants are dispersed and the rate at which the dispersion occurs. The chemical and physical characteristics of the waste form will together determine how the radionuclides and other contaminants partition into any coexisting liquid or gaseous phases and their bioavailability.

2000 List

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

3.2.04, 3.2.08

Related References