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JA8 : Safety Case: process model benchmarking

SRA Key TopicSRA TopicSRA Topic priority
Safety Case (Topic 1 in the SRA) Increase confidence in and further refinement of methods to make sensitivity and uncertainty analyses (Topic 1.3 in the SRA) Medium

Explanation of the contents of the activity

  1. Setting the base line: compilation of principles and methods for obtaining confidence in the long-term safety of geological disposal.
  2. Summary of the scientific basis for performance (PA) and safety assessment (SA) (data, models and computer codes) from Topic 1.1
  3. Compilation of evolution scenarios for geological repositories and their application in the safety case approaches in the individual WM programmes.
  4. Evaluation of the results of sensitivity analyses with identification of existing uncertainties and proof of repository system robustness.
  5. Strategy for further refinement of the PA/SA methods used by the individual WM programmes.

Agreed by a number of WMOs and stakeholders and published by OECD/NEA [7] the ultimate goal “to have confidence” in the long-term safety of geological repositories means “to have reached a positive judgment that a given set of conclusions are well supported”. Site and system specific safety assessments form an essential part of that combining the assessment basis and the performance assessment of the geological repository.

An essential challenge is the safety assessment for long time-scales with the respective uncertainties. In order to increase confidence completeness, consistency and advanced state-of-the-art of the different means and methods used for safety assessments have to be checked and commented.

Short description of activity

  1. Check the identification and conceptualisation of safety relevant features, events and processes; and scenarios (assessment basis).
  2. Check the appropriate assessment models and their present state as well as the completeness of the required data (how good is good enough).
  3. Check the assessment capability and the quality management for proper application of methods, models and data bases.
  4. Evaluate the confidence in the calculated long-term safety.
  5. Elaborate a logical framework for all activities required in the course of assessing, evaluating, enhancing and communicating confidence.

Executive Group