Description

The hydraulic/hydrogeological processes that affect the host rock and other rock units, and the overall hydraulic/hydrogeological evolution of the geosphere. Included are groundwater flow and temporal changes in fluxes and flow patterns. Also included are temporal changes in hydraulic properties of the rock.

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.

Hydraulic processes in the geosphere will influence the evolution of groundwater flow directions and fluxes through the repository and surrounding rocks during repository construction, during operation and later, post-closure. These hydraulic processes may influence the effectiveness of both the EBS and the geosphere barrier. The rate at which groundwater flows through the EBS will depend partly upon the geosphere’s hydraulic characteristics and properties. This rate of groundwater flow will influence the rate of resaturation of the repository following closure and the rate at which the properties of EBS components evolve (since this evolution depends in part on the supply of water and / or solutes). Hydraulic processes may affect the nature of the pathways for transportation of radionuclides and other contaminants in the aqueous phase in the post-closure period. These hydraulic processes may also influence the retardation of radionuclides and other contaminants originating in the repository during future transport from the repository through the geosphere in the aqueous phase.

2000 List

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

2.2.07