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

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

3. IAEA 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 3

4. IAEA 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 4

5. IAEA 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 5

6. IAEA Potential Concept for Methodology 6

7. IAEA Potential Concept for Methodology 7

8. IAEA Representative Categories of Intrusion 8  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

9. IAEA Site and Facility Considerations 9  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

10. IAEA Draft Report from WASSC Subgroup 10  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

11. IAEA Decision-Making 11  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. IAEA Perspective on Cautious Assumptions 12  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. IAEA Practical Considerations 13  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. IAEA …Thank you for your attention

15. IAEA Potential Discussion Topics 15  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.)

16. IAEA 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 16

17. IAEA Additional Ideas 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 17