Description

The degree of knowledge of the existence, location and/or nature of the repository, including reasons (motivation) for deliberate interference with, or intrusion into, a repository after closure with complete or incomplete knowledge.

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

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.

Knowledge and motivational issues are relevant to repository performance and safety because they affect the future responses of humans to the existence of the repository. Future knowledge of the existence, location and nature of a repository will always be subject to some uncertainty. Consequently, there is always some potential for accidental human intrusion to occur, either into the repository itself, or into a plume of radionuclides or other contaminants that may have been released from the repository, but not yet transported to the biosphere. However, if there is a high degree of knowledge about the existence, location and nature of the repository, any human intrusion will probably be deliberate. In contrast, where there is little such knowledge, any human intrusion will probably be accidental. No knowledge at all about the repository implies that any human intrusion would certainly be accidental. Compared to accidental intrusion, deliberate intrusion is more likely to be accompanied by measures that would prevent and / or mitigate adverse environmental impacts from radionuclides or other contaminants. Higher levels of knowledge about the existence, location and nature of a repository are likely to result in more appropriate / effective mitigation measures being available than in cases where there is less knowledge. For intrusion to occur, whether deliberately or accidentally, there will also need to be a motivation, such as seeking resources. Deliberate intrusion could possibly be motivated by an attempt to mitigate the effects of radionuclide releases or other contaminant releases (e.g. an attempt may be made to retrieve certain wastes).

2000 List

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

1.4.02

Related References