Yumiko Kumano Radioactive Waste and Spent Fuel Management Unit

1. Introduction:IAEA activities / Documents on human intrusion TM-42929 Technical Meeting to Discuss Human Intrusion and Future Human Actions in relation to Disposal of Radioactive WasteIAEA Headquarters, Vienna, Austria 24-28 September 2012 Yumiko Kumano Radioactive Waste and Spent Fuel Management Unit Division of Radiation, Transport and Waste Safety - NSRW

2. Overview • Background • IAEA SSs and activities - GSR Part 4 / SSR-5 / DS355 - GEOSAF - PRISM • Consultancy • Work Plan for the WG 2

3. Problem Definition - Background “Concentrate and Contain” philosophyInternationally accepted as most protective approach, but results in potentially greater hazards for future disruption  Consideration of future human actions (not considered for hazardous waste… future human actions is unique) IAEA, ICRP and OECD/NEA • Consideration on inadvertent intrusion to address consequences after institutional control period • No updated international position available on how to incorporate future human actions into SA, siting and design

4. Configuration of IAEA Safety Standards GSR Part 4 SSR5

5. GSR Part 4: Safety Assessment for Facilities and Activities Requirement 12: Assessment of safety over the lifetime of a facility or activity 4.43. In the case of a repository for radioactive waste in significant quantities, radiation risks have to be considered for the post-closure phase. Radiation risks following closure of the repository may arise from gradual processes, such as the degradation of barriers, and from discrete events that could affect isolation of the waste, such as inadvertent human intrusion or abrupt changes in geological conditions.

6. SSR-5 : Disposal of Radioactive waste CONCEPTS RELATING TO DISPOSAL OF RADIOACTIVE WASTE 1.10. …The specific aims of disposal are: (a) To contain the waste; (b) To isolate the waste from the accessible biosphere and to reduce substantially the likelihood of, and all possible consequences of, inadvertent human intrusion* into the waste; * ‘Human intrusion’ refers to human actions that affect the integrity of a disposal facility and which could potentially give rise to radiological consequences. Only those human actions that result in direct disturbance of the disposal facility (i.e. the waste itself, the contaminated near field or the engineered barrier materials) are considered.

7. SSR-5 : Disposal of Radioactive waste (Cont.) RADIATION PROTECTION IN THE POST-CLOSURE PERIOD 2.15. ….A reasonable assurance also has to be provided that doses and risks to members of the public in the long term will not exceed the dose constraints or risk constraints that were used as design criteria. Criteria (c) In relation to the effects of inadvertent human intrusion after closure, if such intrusion is expected to lead to an annual dose of less than 1 mSv to those living around the site, then efforts to reduce the probability of intrusion or to limit its consequences are not warranted. (d) If human intrusion were expected to lead to a possible annual dose of more than 20 mSv to those living around the site, then alternative options for waste disposal are to be considered, for example, disposal of the waste below the surface, or separation of the radionuclide content giving rise to the higher dose. (e) If annual doses in the range 1–20 mSv are indicated, then reasonable efforts are warranted at the stage of development of the facility to reduce the probability of intrusion or to limit its consequences by means of optimization of the facility’s design.

8. Safety Standards - Disposal DS 355 DS 356 The Safety Case and Safety Assessment for Radioactive Waste Disposal Near Surface disposal of RW Specific Safety Guide Specific Safety Guide

9. DS-355:The Safety Case and Safety Assessment for Disposal of RW 1. INTRODUCTION 2. DEMONSTRATING THE SAFETY OF RW DISPOSAL 3. SAFETY PRINCIPLES AND SAFETY REQUIREMENTS 4. THE SAFETY CASE FOR DISPOSAL OF RW 5. RADIOLOGICAL IMPACT ASSESSMENT FOR THE PERIOD AFTER CLOSURE 6. SPECIFIC ISSUES Evolution of the safety case Graded approach Defence in depth Robustness Time frame for the assessment Human intrusion Institutional control Retrievability of waste Appraisal of options 7. DOCUMENTATION AND USE OF THE SAFETY CASE 8. REGULATORY REVIEW PROCESS

10. DS-355:The Safety Case and Safety Assessment for Disposal of RW HUMAN INSTRUSION (6.52-6.65) Near surface disposal facility: • Inadvertent HI should be assumed to occur at some time following the loss of knowledge about the site  Consequences of plausible intrusion scenarios should be assessed (but should not attempt to use a risk based concept) Geological disposal facility: • Relevance of HI scenario is limited due to the depth and location • Timeframe of concern are far too large to enable meaningful estimates  Assessment of HI scenario should be used to demonstrate the robustness of the disposal system * Speculative scenarios / arbitrary boundary conditions * care should be taken for quantitative use

11. PRISM Project: PRactical Illustration and Use of the Safety Case Concept in the Management of Near-Surface Disposal • Objective: To share experience and communicate good practice, in particular concerning: • The components and expectations of the safety case and their evolution over the lifecycle of a near-surface radioactive waste disposal facility • Decision making at different stages in the facility lifecycle, using the safety case • Task Groups: • Understanding the safety case • Disposal facility design • Managing waste acceptance • Managing uncertainty • To be finished in 2012

12. Human Intrusion in PRISM • Working group discussions during the PRISM Plenary meetings, the presentations, papers and examples discussed in the report show disposal facility design may be affected by a wide range of factors including: • ….. • Safety assessment assumptions and results regarding: • Engineered barrier performance and degradation. • Measures to reduce the probability of human intrusion. • …..

13. GEOSAF projectDemonstration of SAFety of GEOlogical disposal • A forum to exchange ideas and experience in developing / reviewing SC • a platform for knowledge transfer • Harmonization in approaches to demonstrating the safety of geological disposal • To identify issues related to the development of the SC that need clarification or further development GEOSAF

14. Consultancy on preparing a initial position paper on future action plans - Purpose Consultancy organized from 26 to 30 March 2012Purpose • To discuss approach to address human intrusion and future human actions in the demonstration of safety of RW disposal facilities • To provide an initial position paper on considerations for addressing future human actions for post-closure SA of RW disposal and to use those assessments to optimise siting, design and waste acceptance criteria Consultants de Mèredieu, J. ANDRA, France Morén, L. SKI, Sweden Seitz, R. Savannah River National Laboratory, USA

15. Work Plan for this TM (1) • Main target: Geological disposal facilities + near-surface disposal facilities • Topics • Past / current activity on HI scenario for both geological / near-surface disposal facilities- difference in scenarios for different disposal concepts- common methodology being applied to all disposal concepts • Discussion on position paper, review and refine • Discussion of setting up an international Working Group to address the issue of human action and human intrusion, review and refine scope of one or more WGs

16. Work Plan for this TM (2) • Terms of Reference for the future WG that includes; - Objectives / Scope /Goal of the WG - Outline of the future TECDOC(?) - Structure of sub working group - Consideration for each sub working group - Plans for future activities Expected outcome Outcomes will be used as an input for developing an IAEA safety document on methodologies for the development of inadvertent human action and human intrusion scenarios

17. Thank You • Working folder: http://gnssn.iaea.org/RTWS/general/Shared%20Documents/Forms/AllItems.aspx?RootFolder=%2FRTWS%2Fgeneral%2FShared%20Documents%2FWaste%20Management%2FSep2012%20TM%20on%20human%20intrusion