Description
The hydraulic processes that affect the seals and other engineered repository features, and the overall hydraulic/hydrogeological evolution of the repository. This includes the effects of hydraulic/hydrogeological influences on the repository components by the waste packages and the surrounding geosphere.
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/hydrogeological processes may influence the physical, chemical and biological evolution of the EBS and the mobility of radionuclides and other contaminants, should these be released from the waste packages and should there be pathways through the other EBS components.
Flowing water may transport microorganisms and solutes to / from engineered barriers. The water and solutes may participate in chemical reactions, which, depending upon the conditions, may be microbiologically mediated. These reactions may influence the effectiveness of the engineered barriers. The rates of chemical reactions will depend partly upon the rate at which flowing water is able to supply reactants and remove reaction products. The rate at which water flows through the repository will influence the rates at which radionuclides and other contaminants are transported, should these be released from the waste packages.
Flowing water may also cause other phases (non-aqueous liquids and gases) to move. There may be consequent implications for the mobility of radionuclides and other contaminants that occur in these other phases. Flowing water may also, if sufficiently rapid, cause the physical modification of certain EBS materials. For example, physical erosion of bentonite buffer may need to be considered.
Flow of water will transport heat and therefore influence the temperature evolution of the repository, with consequences for the rates of chemical reactions. Some heat generated by waste packages will be transported by water that flows through the EBS.
2000 List
A reference to the related FEP(s) within the 2000 NEA IFEP List.
Related References
-
IAEA (), Hydrogeological Investigation of Sites for the Geological Disposal of Radioactive Waste, IAEA TRS-391, International Atomic Energy Agency, Vienna
-
IAEA (), Characterization of groundwater flow for near surface disposal facilities, International Atomic Energy Agency, Vienna, IAEA-TECDOC-1199, http://www-pub.iaea.org/MTCD/publications/PDF/te_1199_prn.pdf, 31 January 2001