Description

The exposure of humans and other organisms to any repository-derived contaminants that might reach the biosphere.

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.

  • 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.

Exposure modes can be broadly categorised as internal and external with respect to the human body or affected non-human biota. Internal exposure means the contaminant enters and may temporarily or permanently reside in the affected organism. External exposure means the contaminant is outside the organism at all times, although radiation and energy might be transferred into the organism.

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.

Radiotoxic and chemotoxic species differ in their ability to affect organisms. Radiotoxic materials can lead to impacts through internal or external exposure. Chemotoxic species are generally only of concern from internal exposure. Chemicals may be sorbed through skin or surfaces of non-human biota, but subsequent impacts are usually from internal exposure. However, there may be exceptions, for example allergic skin reactions that occur with nickel.

2000 List

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

3.3.04

Related References

  • IAEA (), Reference Biospheres for Solid Radioactive Waste Disposal. Report of BIOMASS Theme 1 of the BIOsphere Modelling and ASSessment (BIOMASS) Programme - Part of the IAEA Co-ordinated Research Project, IAEA-BIOMASS-6, International Atomic Energy Agency, Vienna, ISBN 92–0–106303–2, 560, http://www-pub.iaea.org/MTCD/Publications/PDF/Biomass6_web.pdf