Description

The reasons for and the nature and consequences of deliberate intrusion into a repository after closure with complete or incomplete knowledge of the repository.

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.

Deliberate human intrusion is relevant to repository performance and safety because it involves penetrating the repository, which will compromise the barrier system. Depending upon the nature of the human intrusion, it might transport materials contaminated by radionuclides and / or other contaminants from the repository to the biosphere. The potential consequences for repository performance and safety will depend upon the level of technology possessed by the people carrying out the intrusion, the level of knowledge they have about the repository, and the reasons for the intrusion. Intrusion that uses high levels of technology may decrease the likelihood of adverse environmental impacts compared to intrusion that uses low levels of technology. Consequences may include the long-term impacts of disrupting the barrier system and / or the effects or moving material from the repository to the biosphere. Similarly, compared to lower levels of knowledge about the repository, greater levels of knowledge will, for a given level of technological capability, imply a lower likelihood of adverse environmental impacts. Intrusion that is undertaken to remove material, for example waste retrieval, could result in greater impacts to the biosphere than intrusion that is intended purely for exploratory purposes, for example to establish the characteristics of the wastes. Intrusion that is authorised is more likely to observe the requirements of a robust regulatory framework than intrusion that is unauthorised. It follows that unauthorised intrusion is, all other factors being equal, more likely to result in adverse environmental impacts than authorised intrusion.

2000 List

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

1.4.02

Related References

  • NEA (), Future Human Actions at Disposal Sites, A Report of the NEA Working Group on Assessment of Future Human Actions at Radioactive Waste Disposal Sites, Nuclear Energy Agency/Organisation for Economic Cooperation and Development, ISBN 92-64-14372-6, https://www.oecd-nea.org/rwm/reports/1995/nea6431-human-actions.pdf
  • Smith G M, Molinero J, Delos A, Valls A, Conesa A, Smith K, Hjerpe T (), Human intruder dose assessment for deep geological disposal, Posiva Working Report 2013-23, Posiva Oy, Finland, http://www.posiva.fi/files/3301/WR_2013-23.pdf
  • Galson D A, Klos R A, Serres C, Mathieu G, Beuth T, Cormenzana J L (), PAMINA Performance assessment methodologies in application to guide the development of the safety case, Task reports for the third group of topics: biosphere, human intrusion, criteria for input and data selection, European Commission, Deliverable 1.1.3, http://www.ip-pamina.eu/downloads/pamina1.1.3.pdf