1. Addressing Future Human Actions for Safety Assessment
Summary from CSM on Human Action
And Intrusion in Disposal Facilities
Roger Seitz

2. Representative Categories Site- and Repository-Specific Factors
Overview
Background
General Approach
Representative Categories
Site- and Repository-Specific Factors
Regional Practices
Timing and Countermeasures
Decision-making

3. Position paper – Summary
Summary of the Position Paper
General recommendations based on international publications and experiences in MSs
Considerations and initial suggestions on the development of stylised representations of future human action
Suggestions for a methodology to develop stylised inadvertent human intrusion scenarios and implementation for specific disposal site
Identification of topics for a future working group

4. Background - Perspective
Radioactive waste management is conducted in a manner that considers factors not addressed in other industries in respect of potential impacts on future generations  Consideration of future human actions after loss of institutional controls (not considered for hazardous waste)  Consideration of very long time frames “Concentrate and Contain” philosophy Need to maintain perspective regarding the overall benefits of this approach relative to the potentially greater hazards that could result from intrusion

5. Background - Expectations
IAEA, ICRP and OECD/NEA
Protect inadvertent intruder, not advertent intruder
Limited stylized scenarios, current habits
Intrusion considered in the context of intervention and optimization

6. Potential Concept for Methodology

7. Potential Concept for Methodology

8. Representative Categories of Intrusion
Drilling and Excavation/Construction
Considerations for those categories
Direct exposure and/or exposure through groundwater ??
Based on current technologies and human habits
Scenarios should be o illustrative indicators of safety x predictions of safety based on what is expected to occur
Not intended to obtain “yes or no” conclusion, rather to bring additional information for improvements to siting, design or WAC
Role of institutional controls???

9. Site and Facility Considerations
Site Considerations
Natural resources
Groundwater quantity and composition
Soil, rock properties
Land use (role of passive controls)
Design considerations
Effectiveness of barriers (waste, container, facility, site) against intrusion (delay or preclude)
Effect of intrusion (penetration, cuttings, water contamination, etc.)
Source term depletion
Role of institutional controls???

10. Draft Report from WASSC Subgroup
Draft prepared but never published
Addressed many of the topics discussed in March meeting
Systematic approach, Stylized scenarios, Countermeasures
Identified issues related to intrusion
Time scales, Intrusion as a separate event, Probabilities, Inhomogeneities, Overcautiousness
Role of institutional controls???

11. Decision-Making
Not “yes or no”, inform siting, design and WAC (optimisation)
Caution to not create a situation where overly cautious intrusion scenario could cast doubt on a very good site/design
Maintain perspective relative to expectations in other industries

12. Perspective on Cautious Assumptions
Assume loss of control (unique to RW disposal??)
Assume intrusion will occur (unique to RW disposal??)
Assume intrusion occurs immediately following loss of active control?
Assume occurs within footprint of facility rather than outside footprint?
Assume direct contact with waste (or probability of hitting waste)?
Assume contact with higher activity waste (or average)?
Assume barrier is compromised (or assume delay before intrusion)?
Assume drill will not deflect around barrier, container or waste form?
Assume driller/construction worker will not recognize that something is wrong?
Assume resident establishes home/garden in cuttings?
Assume all cuttings are respirable?
Assume cuttings will behave like soil for uptake in plants?
Extreme exposure assumptions rather than similar to typical remediation

13. Practical Considerations
Identify areas where consensus can be reached
Expected to be difficult to obtain consensus on details regarding scenarios because of existing precedents
Focus on efforts that will contribute to a safety report
Capture considerations related to countries working to implement new disposal capability
Geologic and near surface

14. …Thank you for your attention

15. Potential Discussion Topics
Geologic or Near-Surface
Effectiveness of Institutional Controls (land use)
Effectiveness of Barriers (timing)
Use of Stylized Scenarios
Probabilities of Intrusion
Inhomogeneities
Overcautiousness
Interpretation of results (“yes or no”, design support, etc.)
Role of institutional controls???

16. Potential Working Groups from March
Topical areas for a future WG
WG1: Technical Conditions – to address specifics on possible human actions based on site conditions (e.g. type of drilling, well diameter and depth, etc.)
WG2: Societal Aspects – to address societal context of future human action scenarios (e.g. considerations on the level of development of a country, etc.)
WG3: Linking Technical and Societal Conditions with Design – to consider the synthesis of site and societal considerations with the actual repository design to develop the full scenarios to be considered (e.g. considerations on timing of the intrusion activity)
WG4: Practical application of results from analyses considering future human actions – to consider how scenarios regarding future human actions are used in the process of siting, designing and developing WAC – Regulatory and public perception considerations
Initial ideas, these could be reorganized, combined, some could be removed based on the interests of the participants

17. Additional Ideas Considerations:
Divide by geologic and near-surface disposal
Combine technical and societal aspects
Update draft IAEA document into Safety Report
Considerations:
Limit number of groups
Focus on areas where consensus can be reached
Practical expectations, achievable goals
Want to have product(s) that will contribute to a safety report at the end of the project